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Title: American Weasels
Author: Hall, E. Raymond (Eugene Raymond), 1902-1986
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

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  UNIVERSITY OF KANSAS PUBLICATIONS
  MUSEUM OF NATURAL HISTORY
  Vol. 4, pp. 1-466, plates 1-41, 31 figures in text
  December 27, 1951



  AMERICAN WEASELS


  BY


  E. RAYMOND HALL



  UNIVERSITY OF KANSAS
  LAWRENCE
  1951


  UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

  Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
  Edward H. Taylor, Robert W. Wilson

  Vol. 4, pp. 1-466, plates 1-41, 31 figures in text


  December 27, 1951

  UNIVERSITY OF KANSAS
  Lawrence, Kansas


  PRINTED BY
  FERD VOILAND, JR., STATE PRINTER

  TOPEKA, KANSAS
  1951

  23-3758


[Illustration: PLATE 1. Coloration of head and foreparts in ten
subspecies of long-tailed weasel, _Mustela frenata_. All figures are of
males, approximately × 1/2.

In regions of heavy rainfall (see figs. 2 and 3) there is an increase
in pigmentation and extent of blackish color backward over the neck and
a decrease in extent of the white facial markings. In regions
progressively more arid (see figs. 3 to 7) there is a decrease in
pigmentation and extent of blackish color and an increase in extent of
the white facial markings.

As shown by rearing mammals from humid regions in arid regions, and
_vice versa_, the color is not visibly altered in one or a few
generations; the color is an hereditary character. Beginning with the
southernmost subspecies (fig. 1) and continuing northward to the
northern subspecies (fig. 10) there is a darkening, next a lightening,
and finally a darkening closely conforming to amounts of precipitation
in the geographic regions concerned. A fuller discussion of this
correlation is given on page 51.]

[Illustration: FIG. 1. Map showing localities of capture of specimens
depicted in plate 1.]



American Weasels


BY


E. RAYMOND HALL



CONTENTS


                                                                   PAGE

  INTRODUCTION                                                        7

  PALEONTOLOGICAL HISTORY                                            10

  SKELETON AND DENTITION                                             12

  DISPARITY IN NUMBERS OF MALES AND FEMALES                          19

  MATERIALS, ACKNOWLEDGMENTS AND METHODS                             21

  VARIATION                                                          24
  Variation with Age                                                 24
  Secondary Sexual Variation                                         26
  Individual Variation                                               28
  Seasonal Variation                                                 30
  Variation in Coloration and Molt                                   30
  Variations of Taxonomic Worth                                      44

  DISTRIBUTION AND SPECIATION                                        54

  HISTORY OF CLASSIFICATION                                          69
  Chronological List (annotated) of Specific and Subspecific
  Names Applied to American Weasels                                  71

  CHECK-LIST OF AMERICAN SPECIES AND SUBSPECIES OF THE GENUS
  MUSTELA                                                            81

  ARTIFICIAL KEY TO AMERICAN SPECIES OF THE GENUS MUSTELA            83

  DIAGNOSIS OF THE GENUS                                             83

  EXPLANATION OF SYSTEMATIC TREATMENT                                84

  SYSTEMATIC ACCOUNTS OF SPECIES AND SUBSPECIES                      87
  _Mustela erminea_                                                  87
  _Mustela rixosa_                                                  168
  _Mustela frenata_                                                 193
  _Mustela africana_                                                406

  EXPLANATION OF CRANIAL MEASUREMENTS                               417

  TABLE OF CRANIAL MEASUREMENTS                                     418

  LITERATURE CITED                                                  442

  INDEX                                                             461



American Weasels


By E. RAYMOND HALL



INTRODUCTION


The weasel's agility and speed take it in and out of retreats, over
obstacles and across open places in amazingly rapid fashion and are
responsible for the animal's actions being described as "quick as a
flash." The common long-tailed weasel of the United States measures
approximately a foot and a half in length, of which the tail comprises
a third; but the round, slender body is scarcely more than an inch and
a half in diameter. Brown above and whitish below in summer dress, the
animal is sleek as well as lithe and graceful. It is easy to
understand, therefore, why the Bavarian name _Schönthierlein_ (pretty
little creature) and the Italian name _donnola_ (little lady) were
bestowed upon it. The Spanish name is _comadreja_ (godmother).

In the winter, in temperate and northern regions, the coat becomes pure
white except for the black tail-tip. In this dress the correct name for
the animal is ermine, a mammal whose fur is known to all and justly
esteemed, especially for its luster in artificial light, where it is
scarcely excelled in enhancing the beauty of gems and their feminine
wearers.

In relation to its weight, the weasel is thought to be unsurpassed, and
perhaps it is unequalled among mammals, in the effectiveness with which
it exercises its carnivorous heritage; it kills with speed and strength
a wide variety of animals including many much larger than itself; and
it has been known to attack even man himself when he stood between the
weasel and its intended prey. In structure and temperament it is so
highly specialized for offense that, when opportunity affords, it
sometimes kills, for storage in its larder, far more than enough to
meet its immediate needs. After speaking of this tendency, Elliott
Coues (1877:129) has said:

"A glance at the physiognomy of the weasels would suffice to betray
their character. The teeth are almost of the highest known raptorial
character; the jaws are worked by enormous masses of muscles covering
all the side of the skull. The forehead is low and the nose is sharp;
the eyes are small, penetrating, cunning, and glitter with an angry
green light. There is something peculiar, moreover, in the way that
this fierce face surmounts a body extraordinarily wiry, lithe, and
muscular. It ends in a remarkable long and slender neck in such a way
that it may be held at right angle with the axis of the latter. When
the creature is glancing around, with the neck stretched up, and flat
triangular head bent forward, swaying from one side to the other, we
catch the likeness in a moment--it is the image of a serpent." Although
Coues' colorful description more closely links the weasel with the
symbol of evil than pleases me, his description does emphasize the
raptorial character of the weasel.

Even though most weasels are intractable as pets, they have a value to
man, as, for instance, when he is plagued by mice. In a field where
mice and other small rodents are so abundant as to damage cultivated
crops, the weasel is the farmer's best friend. A weasel may inhabit one
den until the rodents thereabouts are almost exterminated in an area
two or three hundred yards across; in this way the weasel acts as a
control, locally, as well as a check more widely, on the increase in
size of populations of kinds of rodents upon which it preys. The
smaller species are mousers of remarkable efficiency and can, if
necessary, follow a mouse to the end of the mouse's burrow. The slender
body allows the weasel to pass through any burrow or hole into which it
can thrust its head. This ability in an organism as highly specialized
for killing other animals as is the weasel, has earned for it a bad
name in connection with poultry yards. Authentic instances are recorded
in which a weasel, gaining entrance through a knot-hole to a coop of
young chickens, killed several dozen of the fowls. In other instances,
however, weasels have lived under buildings close by a poultry yard
without even molesting the birds in the slightest; in the latter
instances the weasels probably were present because there was an
abundant supply of rats and mice. At least three poultry raisers (see
page 214) have encouraged weasels to live in their poultry yards
feeling that the good they do by destroying rats outweighs the damage
caused by the occasional weasel which turns to the fowls; the idea is
that the individual weasel can be eliminated if he becomes destructive.

Although tending to be nocturnal, weasels are almost as active by day
as by night. Their young, numbering 4 to 9, are born in a nest in a
burrow and as with other members of the Order Carnivora, are blind, and
incapable of looking after themselves at the time of birth. In _Mustela
frenata_ of Montana, breeding occurs in July and August, and the young
are born in the following April and May. Wright (1948A:342) showed that
the gestation period could not have been less than 337 days in one
individual and that it averaged 279 (205-337) days in 18 instances.
Findings of the same author (1942B:109) showed that the embryos are
implanted only 21 to 28 days before the young are born. In the
preceding part of the "long gestation period, the embryos lie dormant
in the uterus as un-implanted blastocysts. The young female weasel [of
_M. frenata_] mates when 3 or 4 months old." Consequently, in the
spring, all females of this species may produce young (Wright,
1942A:348). The circumboreal species _Mustela erminea_ likewise has
been shown to have a delayed implantation of the ova. Each of these two
species, _M. frenata_ and _M. erminea_, has only one litter per year;
but the weasel, _Mustela nivalis_, of the Old World seems to lack the
delayed implantation, in this respect resembling the ferret (subgenus
_Putorius_) as it does also in its ability to have more than one litter
per year (see Deanesly, 1944). The manner of reproduction in the South
American species _M. africana_ and the circumboreal species _M. rixosa_
at this writing is unknown.

The genus _Mustela_ includes the true weasels, the ferrets and minks.
The ferrets commonly are treated as a subgenus, _Putorius_, along with
the Old World polecat. The minks usually are accorded subgeneric
distinction under the name _Lutreola_, and the true weasels comprise
the subgenus _Mustela_, the three subgenera together, along with some
other subgenera which are mostly monotypic, comprising the genus
_Mustela_. Considered in this way, the group of true weasels, subgenus
_Mustela_, has a geographic range roughly coextensive with that of the
genus _Mustela_. This range includes Asia and Europe, Northern Africa,
North America and northern South America. Java has its weasel.
Australia and nearly all the oceanic islands lack weasels, and the
animals are absent from roughly the southern half of Africa and the
southern half of South America. Other small mustelids, weasellike in
shape and with corresponding habits and dentition, take the place of
true _Mustela_ in the southern half of Africa and in the corresponding
part of South America.

In America the subgenus _Mustela_ occurs from the northernmost land in
Arctic America southward to Lake Titicaca in the Andes of South
America, a distance of approximately 6900 miles. _Felis_, I think, is
the only other genus of land mammals in the western hemisphere that has
a geographic range as extensive from north to south. _Felis_ does not
range so far north but does range farther south. The one species,
_Mustela frenata_, ranges from Lake Titicaca northward to about 57° N
in British Columbia or for approximately 5000 miles in a north to south
direction and from within the Alpine Arctic Life-zone through the
Tropical Life-zone. In North America, weasels occur in almost every
type of habitat, being absent only in the extremely desert terrain of
western Arizona and western Sonora and in adjoining parts of California
and Baja California. Even this area, along the Colorado River, may
support some weasels; evidence suggesting that it does so is given in
the account of _Mustela frenata neomexicana_.



PALEONTOLOGICAL HISTORY


The paleontological record fails to show the precise ancestry of
_Mustela_. The genus has been found in deposits of Pleistocene age,
but, so far as I can ascertain, not in deposits of earlier times. The
Pleistocene remains are not specifically distinct from Recent (living)
species, and in only a few instances (see _M. f. latirostra_ and _M. e.
angustidens_) are they even subspecifically distinct from the Recent
weasel living in the same area today. It is true that fossil remains
from deposits of several stages of the Tertiary beds have in the past
been identified in the literature as _Mustela_, but most of these
identifications were made many years ago when the generic name
_Mustela_ was used in a far broader and more inclusive sense than it is
today and much of the fossil material was so fragmentary that the
generic identity could not be ascertained, at least at that time.
Because the generic identity could not be ascertained, the fossil
material was tentatively assigned to the genus _Mustela_, the "typical"
genus of the family Mustelidae instead of to some other more
specialized or less well-known genus of the family. To satisfy my
curiosity about these species of "_Mustela_" of a geological age
earlier than the Pleistocene I have personally studied nearly all of
the original specimens from North America and have found each to be of
some genus other than _Mustela_. Also, such study as I have been able
to make of the Old World fossils themselves that have been referred to
the genus _Mustela_ up to 1938, and my study of the illustrations and
descriptions of the others from there lead to the same conclusion; that
is to say, none that is true _Mustela_ is known up to now from deposits
older than the Pleistocene.

When, in 1930 (pp. 146-147), I wrote about the taxonomic position of
three American genera of fossils (known only from lower jaws), each of
which had been previously referred to the genus _Mustela_, I said that
they pertained "to that section of the weasel family (Mustelidae)
which comprises the polecats, true weasels, ferrets, minks and martens.
The fossil specimens . . . are smaller than any other later Tertiary
members of the group yet described, and are more primitive than any of
the above mentioned Recent relatives. Of the three extinct genera . . .
_Miomustela_ [Lower Pliocene or Upper Miocene of the Lower Madison
Valley, Montana] is the most primitive and _Martinogale_ [Pliocene, 18
mi. SE Goodland, Sherman County, Kansas] is the most advanced. This
view rests largely on the character of M_{=1} which in _Miomustela_ has
a deeply basined, short, narrow talonid with a thick, high metaconid
situated partly posterior to the protoconid. In _Martinogale_ the
talonid is incipiently trenchant, long, broad, and it has a lesser
developed metaconid which is situated more anterior [ly]. _Pliogale_
[Lower Pliocene, Humboldt County, Nevada] is intermediate in this
respect.

"These three forms are of special interest as possible ancestors of the
subgenus _Mustela_, true weasels. No members of this subgenus, nor
related forms which can with any degree of certainty be regarded as
directly ancestral to them, have yet been described from Miocene or
Pliocene deposits. _Palaeogale_ of the Old World and _Bunaelurus_ of
North America, each of Oligocene age, have been placed by Schlosser
(1888, p. 116) and Matthew (1902, p. 137) as members of the primitive
group of mustelids ancestral to _Mustela_. This course seems logical;
and with no truly intermediate links between these forms of the
Oligocene on the one hand, and _Mustela_ which first appears in the
Pleistocene, on the other, more definite statements about ancestral
positions of the small Oligocene forms can hardly be made. The deciding
considerations for authors who placed _Palaeogale_ and _Bunaelurus_ as
ancestral to _Mustela_ were the absence of a metaconid on M_{1} and the
trenchant talonid of that tooth. These characters are found also in
_Mustela_. On the other hand certain structures in the basicranial
region of _Palaeogale_ and more especially of _Bunaelurus_ indicate
that these genera possibly are not close to the ancestral form of
Mustela . . . _Martinogale_ may stand near the ancestral form of
_Mustela_ and . . . _Pliogale_ may be ancestral to _Martinogale_.
_Pliogale_, in turn, may have had an ancestor similar to _Miomustela_.
If this should prove to be the case, _Palaeogale_ and _Bunaelurus_
might be regarded as an independent branch which displays merely a
parallelism to _Mustela_ in the loss of the metaconid on M_{1} and the
development of a trenchant talonid on that tooth. The writer would make
it clear that he does not hold such to be the case. The ancestral
relation of _Martinogale_ to _Mustela_ is presented merely to show the
possibility, and not the special probability, of such an origin for
_Mustela_. Knowledge of the tympanic bullae and other structures of the
basicranial region would go far toward answering the question and until
these structures are known [in mustelids of the Later Tertiary,] some
uncertainty will remain."

At the present writing I can add to the above statement only a few
facts. The discovery of better material of _Bunaelurus_ than was
available to previous workers led Simpson (1946), correctly I think, to
synonymize _Bunaelurus_ with _Palaeogale_. Simpson figures the cranial
foramina in _Palaeogale_. The differences, between _Palaeogale_ and
_Mustela_, in cranial foramina, possibly are only the result of the
elongation of the tympanic bullae. The bullae of the subgenus _Mustela_
are seen to be much elongated posteriorly if comparison is made with
the bullae of earlier mustelids. Consequently, it might be concluded
that there is nothing in the arrangement of the cranial foramina which
would preclude the derivation of _Mustela_ from _Palaeogale_. However,
the anterior situation of the carotid foramen--well forward along the
medial margin of the tympanic bulla--is a character typical of other
mustelids and the posterior location of this foramen in _Palaeogale_
might indicate that it was not ancestral to _Mustela_.



SKELETON AND DENTITION


The outstanding features of a weasel's skeleton are its length and
slenderness. Whereas the length of the vertebral column measured from
the atlas (the first cervical vertebra) to the last sacral vertebra is
175 per cent of the length of the hind leg (as measured from the head
of the femur to the tip of the longest claw), the corresponding
percentage is only 116 in the raccoon. Stated in another way, the
vertebral column and the hind leg are of approximately equal length in
a raccoon, but in a weasel the vertebral column is one and
three-fourths times as long as the hind leg.


VERTEBRAE

The vertebral column consists of 7 cervicals, and ordinarily 14
thoracics, 6 lumbars, 3 sacrals and, depending on the species, 11 to 23
caudals. For the three species of which skeletons were examined,
variations from the normal number of vertebrae are noted in the
following table:

TABLE I

Data on vertebrae in three species of the subgenus Mustela (Numerals in
parentheses indicate number of specimens)

  ===================+=========+=========+=========
                     |_Mustela_|_Mustela_|_Mustela_
                     |_erminea_| _rixosa_|_frenata_
  -------------------+---------+---------+---------
  Number of cervical |    (75) |    (12) |    (65)
   vertebrae         |   7     |   7     |   7
  -------------------+---------+---------+---------
  Number of thoracic |    (71) |    (12) |    (54)
   vertebrae         |  14     |  14     |  14
                     +---------+---------+---------
                     |     (4) |         |    (13)
                     |  15     |         |  15
  -------------------+---------+---------+---------
  The dorsal vertebra|    (18) |    (12) |    (40)
    constituting the |  11th   |  11th   |  11th
    anticlinal       +---------+---------+---------
                     |     (7) |         |    (27)
                     |  12th   |         |  12th
  -------------------+---------+---------+---------
  Number of lumbar   |     (2) |         |    (11)
    vertebrae        |   5     |         |   5
                     +---------+---------+---------
                     |    (73) |    (12) |    (54)
                     |   6     |   6     |   6
  -------------------+---------+---------+---------
  Number of sacral   |     (9) |         |     (3)
     vertebrae       |   2     |         |   2
                     +---------+---------+---------
                     |    (65) |    (10) |    (67)
                     |   3     |   3     |   3
                     +---------+---------+---------
                     |     (1) |     (2) |
                     |   4     |   4     |
  -------------------+---------+---------+---------
  Number of          |    (73) |    (12) |    (57)
    pseudosacral     |   0     |   0     |   0
    vertebrae        +---------+---------+---------
                     |     (2) |         |     (6)
                     |   1     |         |   1
  -------------------+---------+---------+---------
                     |         |     (1) |
                     |         |  11     |
                     +---------+---------+---------
                     |         |     (3) |
                     |         |  14     |
                     +---------+---------+---------
                     |     (2) |     (7) |
                     |  15     |  15     |
                     +---------+---------+---------
                     |     (3) |     (1) |
                     |  16     |  16     |
                     +---------+---------+---------
                     |     (9) |         |
                     |  17     |         |
                     +---------+---------+---------
  Number of caudal   |    (28) |         |
  vertebrae          |  18     |         |
                     +---------+---------+---------
                     |    (11) |         |     (6)
                     |  19     |         |  19
                     +---------+---------+---------
                     |         |         |    (14)
                     |         |         |  20
                     +---------+---------+---------
                     |         |         |    (14)
                     |         |         |  21
                     +---------+---------+---------
                     |         |         |     (7)
                     |         |         |  22
                     +---------+---------+---------
                     |         |         |     (1)
                     |         |         |  23
  -------------------+---------+---------+---------

Variation according to the species is evident in the number of caudal
vertebrae, but in the other categories of vertebrae no consistent
difference in number according to species was found in the material
examined. Apparently there is also some geographic variation in the
number of caudal vertebrae within a species. For example, the one
skeleton seen of _Mustela rixosa eskimo_ (no. 219036, U. S. Nat. Mus.,
from St. Michaels, Alaska) has only 11 caudal vertebrae, whereas in the
11 _Mustela rixosa rixosa_ from Roseau County, Minnesota, the usual
number is 15 with extremes of 14 and 16. Similarly specimens of
_Mustela frenata_ from Idaho and California almost always have 1 or 2
more caudal vertebrae than do individuals of the shorter-tailed
subspecies of the same species from eastern Kansas.

Of the vertebrae, only the cervicals, of which there are 7, were found
to be constant in number. In _M. erminea_, two of the seven individuals
in which the anticlinal vertebra was the 12th (instead of the 11th) had
15 instead of the customary 14 thoracic vertebrae. In _M. frenata_,
seven of the twenty-seven individuals in which the anticlinal vertebra
was the 12th (instead of the 11th) had 15 instead of 14 thoracic
vertebrae. The one _M. erminea_ with a pseudosacral vertebra had only
two instead of the customary 3 sacral vertebrae but the same individual
had 15 thoracic vertebrae. Of the six _M. frenata_ with a pseudosacral
vertebra, two animals had only two instead of three sacral vertebrae.
Conceivably, therefore, the pseudosacral vertebra in each of the three
instances mentioned may represent merely an unfused sacral vertebra,
instead of a true pseudosacral as occurs in four individuals of _M.
frenata_.


TEETH

In American weasels, for example in _Mustela frenata_, the permanent
dentition normally is

  I  3  C  1  P  3  M  1
  -, -, -, -, -, -, -, - or 34 teeth in all. In most respects the
  i  3  c  1  p  3  m  2

dentition is typical for post-Tertiary mustelids but in several parts
is highly specialized for a diet of flesh, the degree of this
specialization being second only to that of the cats, family Felidae.
The outstanding specialization is in the first lower molar, in which,
as in the cats, the internal cusp (metaconid) is completely suppressed
and the heel (talonid) forms an elevated blade for cutting food rather
than a basin for crushing it. In one sense the tooth is simplified
since it owes its distinctive form to a reduction in number of parts;
nevertheless, the distinctive form of the lower molar clearly is
correlated with a diet of flesh, and the tooth is correctly to be
thought of as the lower blade of a pair of shears; the upper blade is
the fourth upper premolar. The reduction in size of the second (last)
lower molar and small size of the inner lobe of the one remaining upper
molar probably are additional modifications for a diet of flesh.

The absence of the last two upper molars and last molar in the lower
jaw would be expected in any mammal as highly specialized for a diet of
flesh as is the weasel, but these teeth are absent also in other
Quaternary members of the family Mustelidae, many of which are
substantially less specialized for a diet of flesh than is the weasel.
Therefore, in the weasel, it is reasonable to regard the absence of
these teeth more as a heritage than as an indication of a special
adaptation. The absence of a first premolar above and below, as in the
weasel, is to be expected in any carnivore that has the first lower
molar and fourth upper premolar highly specialized for shearing, but
the loss of these premolars and the small size of the second premolars
may be as much the result of a slight shortening of the face as it is a
result of a lengthening of the third and especially the fourth
premolars. The lengthening of these more posteriorly-situated teeth
would appear to be an adaptation to a diet of flesh. The cause of the
lengthening of the mentioned teeth and the reason for the absence of
the first premolars probably will be unknown until the fossil record is
more complete.

The teeth of American species vary little except in size. The absence
of P2 in _Mustela africana_ is the only difference of a qualitative
(presence or absence) nature that was detected. Also, the Central
American subspecies of _Mustela frenata_ exhibit a tendency to early
loss of P2 and thus foreshadow the condition typical of _M. africana_.

As a whole the dentition of the weasel exhibits a high degree of
specialization for a diet of flesh and this specialization is fully as
evident in the deciduous dentition as in the permanent dentition.

The deciduous, or milk, dentition, of _Mustela frenata_, as known from
immature specimens of _Mustela frenata noveboracensis_ and _Mustela
frenata frenata_ available for this study, is comprised of canines, one
on each side above and below, and 3 cheek teeth on each side above and
below. See figures 2-9. The upper cheek teeth from anterior to
posterior are: a minute peglike tooth in general similar to the first
premolar of the permanent dentition; a shearing tooth in general
similar to P4 of the permanent dentition; and an anteroposteriorly
compressed tooth in general similar to M1 of the permanent dentition.
In the lower jaw, behind the canine, there is first a minute peglike
tooth, second a two-rooted tooth similar in general outline to a
permanent third premolar, and finally a shearing tooth corresponding in
function to m1 of the permanent dentition.

No postnatal specimens which show deciduous incisors have been
examined.

Selected, outstanding differences between the permanent teeth and the
deciduous teeth are as follows: In the deciduous teeth the canine above
has on the posterior face a well-defined ridge extending from the tip
to the cingulum. This ridge is absent or at most faintly indicated in
the permanent tooth. The lower deciduous canine, in cross section is
seen to have a marked indentation on the anteromedial border in the
region of the cingulum; this indentation is lacking in the permanent
tooth. The anterior one of the deciduous cheek teeth, both above and
below, is single rooted and its crown-surface is only about
one-fifteenth as much as that of the anterior premolar of the permanent
dentition. The second deciduous cheek tooth below has two roots,
usually fused, and differs from p4 of the permanent dentition in having
the tip of the principal cusp more recurved, in having the anterior
basal cusp better developed and the posterior heel less well developed.

The second deciduous cheek tooth above corresponds in function and
general plan of construction to P4 of the permanent dentition but
differs from that tooth in the more pronounced protostyle, longer
tritocone, more posteriorly located deuterocone and as noted by Leche
(1915:322) separation of the protocone and tritocone by a notch. The
third upper deciduous tooth has a single cusp internally and two cusps
laterally. Thus it reverses the relation of parts seen in M1 where the
internal moiety is larger than the lateral or buccal moiety. The third
deciduous tooth below differs from m1 in very much shorter talonid and
separation of the paraconid from the protoconid by a deeper notch.

All the features in which the last two deciduous teeth, both above and
below, are described as differing from their functional counterparts in
the permanent dentition, are features found in the permanent teeth of
primitive fossil mustelids and certain fossil and Recent viverrids.
Even so, taking into account Leche's (1915) work, which shows that the
milk teeth of some carnivores have structures lacking in the
corresponding permanent teeth of the same individual animal and also in
the teeth of genera that seem to be ancestral, a person suspects that
some of the structural features mentioned above are not inheritances
of ancestral conditions but rather specializations of the milk
dentition.

[Illustration: FIGS. 2-9. Views of permanent and deciduous teeth of
_Mustela frenata nigriauris_. Incisors not shown. In each instance
teeth are of the left side.

Permanent dentition × 3. No. 32421, Mus. Vert. Zoöl., [M], adult;
Berkeley, Alameda County, California; obtained October 4, 1921, by D.
D. McLean.

Deciduous dentition × 5. No. 132158, U. S. Nat. Mus., [M], juvenile;
Stanford University, Santa Clara County, California; obtained May 7,
1898, by W. K. Fisher.

Figs. 2-3. Lateral views of upper teeth, of adult and juvenile
respectively.

Figs. 4-5. Occlusolingual views of upper teeth of adult and juvenile
respectively.

Figs. 6-7. Lateral views of lower teeth of adult and juvenile
respectively.

Figs. 8-9. Occlusolingual views of lower teeth of adult and juvenile
respectively.]

In other deciduous teeth there is clearer evidence of more
specialization for a diet of flesh in the deciduous teeth than in the
permanent teeth. For example, the upper carnassial of the milk
dentition is even more highly sectorial than is the permanent tooth
and strikingly like that of some of the cats. The lower tooth that is
effective in the shearing action bears no more trace of the metaconid
than does the permanent first lower molar. These features of the
deciduous dentition suggest that it is more specialized for a diet of
flesh than is the permanent dentition. If this be the fact, it may seem
especially remarkable because the commonly employed term "milk teeth"
suggests that the animal makes but little or no use of these teeth in
the short time that they are in place. Accordingly, the student may
credit the form of these teeth more to some indirect effects of
inheritance than to natural selection acting directly upon the teeth.
But, after all, natural selection probably is responsible for the form
of these teeth as is indicated by the observations of Hamilton
(1933:318-325). He found that these milk teeth are used for eating
solid food as soon as the principal shearing teeth are in place. This
is three weeks after birth and before all of the deciduous teeth have
broken through the gums. These shearing teeth are used for almost two
months before being replaced by the permanent teeth and it is,
therefore, evident that natural selection could operate to fully as
great a degree in determining the form of the deciduous teeth as it may
with the permanent teeth.

Hamilton (1933:325-326) found that the permanent dentition was complete
at 75 days after birth in captive specimens of _Mustela frenata
noveboracensis_. In the same subspecies, he noted 28 days after birth
that the canines and carnassial teeth [second deciduous cheek tooth
above and third below] had erupted through the gums. Animals 45 days
old, Hamilton found, were losing the milk dentition, and had the gums
broken through by several of the permanent cheek teeth.

Study of the cleaned skulls available of juveniles indicates that the
deciduous teeth which persist longest are, on each side of the mouth,
the second cheek tooth above and the third cheek tooth below. These
teeth persist until after the permanent P4 and m1 have come into use.
These permanent teeth are situated immediately behind their functional
counterparts of the milk dentition. P3 and p4 are the teeth of the
permanent dentition which ultimately push out the last milk teeth to be
lost. Accordingly, in the permanent dentition, P4 and M1 appear before
P3 does, and m1 and m2 make their appearance before p4.



DISPARITY IN NUMBERS OF MALES AND FEMALES (IN ZOOLOGICAL COLLECTIONS)


The question has frequently been asked why twice as many male as female
weasels are captured. This is the proportion in research collections,
as may be seen from table no. 2, and I am convinced that the specimens
in these collections are saved in approximately the same proportion as
that in which they are caught. Although it might be assumed, upon first
consideration, that there are twice as many males as females in nature,
selective factors enter into the catch. For example, because a male
weasel is approximately twice as heavy as a female, it may be necessary
for him, in a given length of time, to travel twice as far as the
female to obtain the required amount of food with the result that a
given number of traps or snares will catch twice as many males as
females. Indeed, Glover (1943B:8) shows that, on the average, in
_Mustela frenata noveboracensis_ in Pennsylvania, the male actually
does travel slightly more than twice as far as the female (704 feet
versus 346 feet). From table no. 2, it may be seen that in most winter
months the ratio is 3 males to one female. This ratio is reasonable
enough, in view of what has been said, if it is considered also that
the lighter weight of the female permits her safely to step on the pans
of traps that would be sprung by heavier males.

If in the breeding season, which is April through August in _M.
frenata_, the female is passive and if the male is restlessly searching
for her, he may thus increase still more his chances of being caught in
traps set for weasels.

My own studies of live weasels in nature indicate that in the season
when females are attending young which are half grown, or larger, the
adult male weasels live singly in dens of their own, separate and apart
from the females and their young (Hamilton, 1933:328, records adult
males living with the female and her young, but possibly this was when
the young were less than half grown). Perhaps these males at that time
travel no farther than is necessary to obtain food for themselves.
Females, at this time, forage not only to meet their own needs, but for
food to supply their young as well. At this time, in May and June, as
may be seen from table no. 2, almost as many adult females as adult
males _are_ caught. The reason why only relatively more females than in
other months, instead of actually more females than males, are caught
at this time probably is that the adult males also are extraordinarily
active at this time because they are in breeding condition. Perhaps
the explanation in part is to be found in the lesser weight of the
female (approximately half of the male's weight) which, as indicated
above, permits her to step on the pan of a steel trap without springing
it whereas the heavier male does spring the trap and as a consequence
is caught. Hamilton (1933:299-300), who mentions this selective factor,
found an equal number of males and females in the three newly born
litters that came under his observation.

TABLE 2

Specimens of _Mustela frenata_ (north of the range of _M. f. frenata_)
arranged by sex and under each sex by age

  KEY:
  A: adult [M]
  B: [M] ad., % of total adults
  C: subadult [M]
  D: young [M]
  E: juvenal [M]
  F: total number of [M]
  G: [M] % of total
  H: adult [F]
  I: [F] ad., % of total adults
  J: subadult [F]
  K: young [F]
  L: juvenal [F]
  M: total number of [F]
  N: [F], % of total
  O: total number of [M] and [F]
  P: total number of adults, [M] and [F]

           /-----------Male---------\/--------Female--------\
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
           | A | B | C | D | E| F | G| H | I| J| K | L| M | N|   O | P
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  May      | 29| 55|  4| 14| 7| 54|59| 24|45| 1|  9| 3| 37|41|   91| 53
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  June     | 42| 53| 14| 40| 8| 97|59| 38|47| 4| 25| 2| 69|41|  166| 80
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  July     | 59| 70| 18| 55| 2|130|59| 25|30| 5| 58| 2| 90|41|  220| 84
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  August   | 40| 77| 23| 55|..|113|74| 12|23| 2| 25|..| 39|26|  152| 52
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  September| 15| 79| 25| 12| 1| 51|75|  4|21| 4|  9|..| 17|25|   68| 19
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  October  | 11| 58| 46|  7|..| 43|66|  8|42|13|  1|..| 22|34|   65| 19
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  November | 41| 70| 48|  1|..| 88|73| 18|30|12|  2| 1| 33|27|  121| 59
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  December | 59| 69| 43|  1|..|108|73| 26|31|15|...|..| 41|27|  149| 85
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  January  | 80| 69| 32|  2| 1|126|72| 36|31|14|...|..| 50|28|  176|116
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  February | 45| 66| 19|  5|..| 82|73| 23|34| 4|  3|..| 30|27|  112| 68
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  March    | 38| 72|  2|...|..| 57|70| 15|28| 8|  1|..| 24|30|   81| 53
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
  April    | 30| 67|  2|  4| 3| 39|67| 15|33|..|  2| 2| 19|33|   58| 45
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---
    Totals |489| 67|281|196|22|988|68|244|33|82|135|10|471|32|1,459|733
  ---------+---+---+---+---+--+---+--+---+--+--+---+--+---+--+-----+---

I suppose that in nature there are approximately equal numbers of male
and female weasels and further suppose that the selective factors which
cause more males than females to be caught are the greater distances
traveled by the males and their greater weight.



MATERIALS, ACKNOWLEDGMENTS AND METHODS


At a late stage in the preparation of this manuscript a total of 5,457
specimens had been examined. For the most part these were conventional
study-specimens; that is to say, they were stuffed skins with the
skulls separate and each was accompanied by the customary data as to
locality of capture, date of capture, name of collector, external
measurements and sex recorded on the labels by the collectors. Skulls
unaccompanied by skins, nevertheless, comprised a large share of the
total and a small proportion was made up of skins unaccompanied by
skulls, mounted specimens, skeletons, and entire animals preserved in
liquid.

     It was the recognition of this need for specimens from extensive
     areas from which no specimens previously had been collected that
     influenced me, approximately a year after the study was begun, to
     allot for it a long span of time. The procedure adopted, in
     general, was to study the weasels of one species from a given
     geographic area in so far as the material warranted, then lay this
     aside until additional critical material could be obtained, and
     finally, some months or a year later, complete the account. In
     this fashion the manuscript of the American weasels received my
     attention in each of the past twenty-five years (September, 1926
     to date of publication). This is a confession of fact rather than
     a recommendation of procedure. This type of procedure unduly
     delays the diffusion of knowledge and for a variety of reasons
     justifiably annoys other students of the subject. Nevertheless,
     many gaps have been filled that otherwise would have remained
     open. Although specimens to solve several problems still remain to
     be collected and studied, it seems that a point of diminishing
     returns has now been reached, which, in fairness to all concerned,
     calls for publication of the results so far obtained.

     For assistance in the entire undertaking, I am more indebted to
     Miss Annie M. Alexander than to any other one person; she provided
     the means by which specimens from critical areas were obtained,
     made it possible to examine the European collections, and assisted
     in other ways. The late Professor Joseph Grinnell and Mr. Charles
     D. Bunker, among others, gave truly valuable encouragement and
     assistance.

     Collections containing weasels which were examined in the study
     here reported upon were as follows:


Acad. Nat. Sciences of Philadelphia
American Mus. Nat. History
Baylor University
Berlin Zoological Museum
Boston Society of Natural History
Brigham Young University
British Museum of Natural History
California Academy of Sciences
Carnegie Museum
Charleston Museum
Coe College
Collection of J. Arnold
Collection of Stanley C. Arthur
Collection of Rollin H. Baker
Collection of William Bebb
Collection of R. H. Coleman
Collection of Ian McTaggart-Cowan
Collection of Stuart Criddle
Collection of John Cushing
Collection of Walter W. Dalquest
Collection of William B. Davis
Collection of J. M. Edson
Collection of Ralph Ellis
Collection of John Fitzgerald, Jr.
Collection of Mr. Green
Collection of Ross Hardy
Collection of Donald V. Hemphill
Collection of L. M. Huey
Collection of R. W. Jackson
Collection of Stanley G. Jewett
Collection of E. J. Koestner
Collection of J. E. Law
Collection of A. H. Miller
Collection of Lloye H. Miller
Collection of R. D. Moore
Collection of J. A. Munro
Collection of O. J. Murie
Collection of Robert T. Orr
Collection of Arthur Peake
Collection of Kenneth Racey
Collection of William B. Richardson
Collection Rocky Mt. Spotted Fever Lab.
Collection of Victor B. Scheffer
Collection of William T. Shaw
Collection of O. P. Silliman
Collection of W. E. Snyder
Collection of Frank Stephens
Collection of T. C. Stephens
Collection of D. D. Stone
Collection of Myron H. Swenk
Collection of Joe and Dean Thiriot
Collection of John Tyler
Collection of Jack C vonBloeker
Collection of Alex Walker
Collection of Edward R. Warren
Colorado Museum of Natural History
Charles R. Conner Museum
Cornell University
Donald R. Dickey Collection
Field Museum of Natural History
Florida State Museum
Fresno State Junior College
Humboldt State Teachers College
Illinois Natural History Survey
Iowa State College
Iowa Wesleyan College
Kansas State Agric. College
Leland Stanford Junior University
Leningrad Academy of Science
Los Angeles Mus. Hist. Art and Sci.
Louisiana State University
Mt. Rainier Nat'l Park Collection
Museum of Comparative Zoölogy
Mus. Polonais d'Hist. Nat., Warsaw
Mus. Vert. Zoöl., Univ. California
Museum of Zoölogy, Univ. Michigan
National Museum of Canada
Naturhistoriska Ricksmuseum, Sweden
Neuchatel University Museum
New York State Museum
Ohio State Museum
Oklahoma Agric. and Mech. College
Ottawa University, Kansas
Paris Museum
Provincial Museum of British Columbia
Royal Ontario Museum of Zoölogy
San Diego Society of Natural History
State Hist. and Nat. Hist. Soc. Colo.
State Normal School, Cheney, Wash.
Texas Cooperative Research Collection
United States National Museum
University of Arkansas
Univ. California Mus. Palaeo.
University of Idaho
Univ. Kansas Mus. Nat. History
University of Minnesota
University of Notre Dame
University of Oklahoma
University of Oregon
University of South Dakota
University of Utah
Univ. Washington Museum of Zoölogy
University of Wisconsin
Univ. Zool. Mus., Copenhagen

     The largest single collection is in the United States National
     Museum, where the specimens of the National Museum proper and the
     United States Biological Surveys Collection, together, provide
     essential materials including a large share of the holotypes.
     Specimens in all of the North American collections including
     Canada and México have been made available, by loan, and in 1937
     materials were examined in the principal collections of northern
     and central Europe. After the materials in North American
     collections were assembled, special effort, with considerable
     success, was made in each of several winters, to obtain specimens
     from areas not previously represented in collections.

     To the many persons who were in charge of the collections
     consulted, to those who at my request sought critical specimens,
     and to those who assisted in various stages of assembling data and
     in preparation of the manuscript, I am grateful indeed. Likewise,
     I am deeply appreciative of the grants-in-aid received from the
     Carnegie Institution of Washington, the University of California
     Chapter of Sigma Xi, the John Simon Guggenheim Memorial Foundation
     and the Kansas University Endowment Association. I am mindful also
     of an obligation to those who appropriated funds, by legislative
     action, for research use by The University of California and The
     University of Kansas.

     For assistance with the illustrations I am indebted to the late
     Major Allan Brooks for Plate 1, to Mrs. Mary Blos for figures
     25-31, to Miss Ann Murray for figures 11-13, to Mr. W. C. Matthews
     for all the photographs, to Mrs. Freda L. Abernathy for figures
     2-9, 18-22, 24, and for retouching all the photographs except the
     following which were retouched by Mrs. Virginia Unruh: figs. _d_
     of plates 2, 3, 4, 9, 10, 11, 16, 17; figs. _i_ of plates 5, 6, 7;
     figs, _h_, _j_, _k_ of plate 7; figs. _f_ and _g_ of plates 12 and
     13; and figs. _c_ and _d_ of plate 14. To Mrs. Unruh I am further
     indebted for figures 1, 16, 17 and 23 and for much terminal
     assistance with preparing most of the illustrations for the
     engraver.

The methods of study, after specimens were assembled, included first
comparisons of specimens of like age and sex from each of several
localities to ascertain the constant features by which full species
were distinguishable, one from the other. For example, it was found
that in every individual from Trout Lake, Washington, of the species
here designated _Mustela erminea_, the postglenoidal length of the
skull amounted to more than 47 per cent of the condylobasal length
whereas it was less than 47 per cent in all individuals here designated
as _Mustela frenata_, from the same locality. Testing of specimens from
other localities by means of this and other selected characters
permitted the outlining of the geographic ranges of the full
"species-groups." By comparing specimens of other nominal species and
by examining specimens from localities geographically intermediate
between the nominal species, I found intergradation and therefore
arranged the nominal species as subspecies of a single species.
Intergradation here is understood to be the result of crossbreeding in
nature between two kinds of animals in the area where the geographic
ranges of the two kinds meet. Presence of intergradation between two
kinds of weasels was basis for according them subspecific rank. Absence
of intergradation in nature at every place where the geographic ranges
of two kinds met or overlapped, and absence of intergradation by way of
some other kind, or chain of kinds, was basis for according each of the
two kinds full specific rank. By thus applying the test of
intergradation, or lack of it, I found that there were four full
species of weasels, of the subgenus _Mustela_, in all of the Americas.

Next, the specimens of one species were arranged in trays in a
geographic sequence. The specimens from any one locality were
segregated by sex and under one sex from one place were arranged from
oldest to youngest, that is to say by age. The four series with the
largest numbers of individuals of a given age were selected. Seventeen
cranial measurements and three external measurements were recorded for
each individual of each of these four series. For each measurement, the
coefficient of variation, standard deviation and probable error were
computed. The four samples subjected to such analysis were a series of
adult males, one of adult females, one of subadult males and one of
subadult females. Also, studies of each sex were made to ascertain
seasonal changes in pelage. After data were obtained on ontogenetic
(age) variation, secondary sexual variation, seasonal variation, and
degree of individual variation by studying specimens in the manner
described above, tests were made for subspecific (geographic) variation
by comparing series of specimens of like sex, age and season, from
different localities. For each one of several geographically variable
features noted, a map was prepared for animals of each sex. When all
the data thus obtained were codified, subspecific ranges were, in a
sense automatically, obtained. On the resulting map showing geographic
ranges of subspecies for a species, a type locality was accurately
plotted for each name that had been applied to the species, and names
then were applied in accordance with the international rules of
zoölogical nomenclature.



VARIATION


Variation with Age

The kind of variation which results from increasing age has been dealt
with extensively for the skull (of the Old World _Mustela erminea_) by
Hensel (1881) and for the external features and to some extent for the
skull by Hamilton (1933) in the North American forms _M. erminea
cicognanii_ and _M. frenata noveboracensis_.

The young of both _erminea_ and _frenata_ are hairless and blind at
birth. In _M. frenata noveboracensis_, the eyes open on approximately
the 37th day. When 2 to 4 months old, the tail is pointed at the tip.
This is because the terminal hair of the tail, including the black tip,
is short and lies flat on the tail. In subadults and adults the hair on
the terminal part of the tail is as long as that on the basal part, and
the tail appears to be of uniform diameter all the way out to the end.

In the western subspecies of _M. frenata_, and in its tropical
subspecies, animals so young as to have pointed tails commonly have the
underparts of the body more intensely colored than do adults. The young
may have salmon-colored instead of yellowish fur on the underparts.

Otherwise, in animals that have attained approximately adult
proportions--which appears to be at approximately 6 months of age in
males--there are no variations which are ascribable to increasing age
in the color-pattern or pelage that cause the systematist to confuse
species or subspecies.

Of the several parts of the skull in juvenal animals, the braincase and
width of the posterior part of the palate are most nearly of the size
attained in the adult, the facial part of the skull at birth is the
least developed, and the interorbital region is, in relation to its
ultimate adult size, intermediate in stage of development. The
permanent teeth are acquired when the animal is approximately eleven
weeks old.

Four age groups, based on characters of the dentition and skull, have
been recognized. They are:

     Juvenile.--One or more deciduous (milk) teeth present. Birth to
     three months of age.

     Young.--Sutures widely open between the maxillae and nasals and
     between the premaxillae and nasals. Three to seven and a half
     months of age.

     Subadult.--Sutures between maxillae and nasals visible but
     indistinct. Seven and a half to ten months of age.

     Adult.--Bones of rostrum coalesced with no traces of sutures
     visible to the naked eye. More than ten months old.

The skull as a whole increases in size until the animal is two-thirds
of the way through the stage designated as young. After this time the
width of the rostrum, as measured across the hamular processes of the
lacrimals, increases until approximately a third of the way through
adulthood. The interorbital breadth decreases from late subadulthood to
adulthood and even in adults there appears to be a slight decrease in
this part of the skull with increasing age.

The average zoölogist will readily distinguish skulls of juveniles and
young from adults but usually fails to distinguish subadults from
adults. Nevertheless, subadults must be distinguished from adults if
geographic variation is to be measured accurately. The reason for this
is that such differences in the form (not size) of the skull as result
from increasing age equal and often exceed the differences of a
geographic sort which serve for distinguishing subspecies that have
adjoining geographic ranges. All sutures in the skull, except those
between the tympanic bulla and the braincase, and those on the dorsal
face of the rostrum, are obliterated while the animal is a subadult.
Most kinds of mammals retain sutures throughout life or until the
animals are well into adulthood. Therefore, skulls of weasels offer
fewer features for estimating age than do those of most mammals and the
skulls of weasels that are subadults or older are more difficult to
classify accurately as to age than are the skulls of most other
mammals. More reliance on shape of entire skull and less reliance on
extent and shape of any individual bone is necessary in estimating the
age of a weasel. Wright (1947:344) shows that the weight of the baculum
(os penis) is a certain means of differentiating adults from males of
lesser age. When approximately eleven months old, _Mustela frenata
oribasus_ of western Montana molts from the white winter coat into the
brown summer coat. At that time spermatogenesis starts for the first
time and the weight of the baculum increases from less than 30
milligrams to more than 52 milligrams.

In the autumn and early winter, most of the specimens are subadults.
Ordinarily the few adults obtained in these seasons can easily be
segregated from the subadults because ontogenetic development in the
twelve additional months of life of each of the older animals has
obliterated the sutures on the rostrum, heightened (vertically) and
lengthened (anteriorly) the sagittal crest, widened the rostrum, and
produced still other changes in form that are revealed by direct
comparison of specimens of the two ages.


Secondary Sexual Variation

The secondary sexual variation, which has been detected, is in size of
the animal, relative length of the tail and shape of the skull. The
female is the smaller. In the small _Mustela rixosa_ and apparently in
_Mustela africana_ the secondary sexual difference in size is
relatively slight. In _Mustela frenata_ and _Mustela erminea_, males
are approximately twice as heavy as females, the degree of difference
very definitely depending upon the subspecies. For example, in _M. e.
richardsonii_ the recorded weights are 175 and 69 grams as opposed to
81 and 54 grams in _M. e. cicognanii_. In general, within one species
the greatest difference in size of males and females is in those
subspecies in which the animals are of large size. The secondary sexual
variation in size is much more than the individual variation in either
sex. The same is not true of secondary sexual difference in length of
the tail (relative to the length of the head and body), which in
eighteen subspecies of _M. erminea_ is from 1 to 7 per cent longer in
males than in females. In two subspecies, _M. e. haidarum_ and _M. e.
olympica_, the tail is a fraction of a per cent the longer in females
if we may rely upon the few specimens for which collectors'
measurements are available.

In both _M. erminea_ and _M. frenata_ the skull of the female is
approximately 45 per cent lighter than that of the male, or put in the
opposite way, the skull of the male is 83 per cent heavier than the
skull of the female. The difference in this respect varies greatly
depending on the subspecies. For example, the skull of the male is 127
per cent heavier than that of the female in _M. e. richardsonii_ but
only 33 per cent heavier in _M. e. anguinae_. In _Mustela frenata_, the
subspecies _noveboracensis_ shows most sexual dimorphism in weight of
skull (3.6 and 1.7 grams) and _olivacea_ the least (5.3 and 3.8 grams).
In general, the difference in this respect is less in subspecies the
individuals of which are of small size.

Therefore, as might be expected, the secondary sexual variation in
weight of the skull is less in _M. rixosa_, individuals of which are of
small size, than in _M. erminea_ or than in _M. frenata_, in general of
larger size. Nevertheless, in _M. africana_, in which the individuals
are of large size, there appears to be less sexual dimorphism in weight
of the skull than in _M. frenata_ or than in _M. erminea_, although it
should be remarked that there are too few data for _M. africana_ to
allow of forming a trustworthy conclusion concerning the amount of
secondary sexual variation in that species.

The secondary sexual variation in shape of the skull consists of a
slenderness in the female. In relation to the basilar length the spread
of the zygomatic arches is more in males and, except in the one
subspecies _M. f. altifrontalis_, the rostrum is broader. Also the
interorbital region is relatively broader in males of most subspecies.
In most subspecies of both _M. frenata_ and _M. erminea_ the tympanic
bullae are relatively (to the basilar length) longer in females. The
maximum sexual dimorphism occurs in _M. erminea arctica_ and the
minimum dimorphism in _M. e. haidarum_, _M. e. anguinae_ and _M. e.
muricus_. Taking into account all of the subspecies of each of the
North American species, the shape of the skull differs most in _M.
erminea_ and least in _M. frenata_. In the latter species the greatest
difference in shape of the skull, as was true also of its weight, is in
the subspecies _M. f. noveboracensis_. In these two subspecies, _M. f.
noveboracensis_ and _M. e. arctica_, in addition to the secondary
sexual variation already mentioned in the skull, females have the
braincase smoother and more rounded, the postorbital-, mastoid-, and
lacrimal-processes relatively smaller, and the ventral face of the
tympanic bulla at its anterior margin more nearly flush with the floor
of the braincase.

In the weasels, subgenus _Mustela_, the disparity in size of the two
sexes is almost or quite as much as in any other fissiped carnivore. It
is because of this large degree of difference that the skulls of the
two sexes are described separately in the following systematic
accounts. The need for such treatment was recognized by Reinhold Hensel
(1881:127) more than sixty years ago when he wrote in the introduction
to his "Craniologische Studien," of _Mustela_, as follows: ". . . die
Geschlechtsdifferenzen am Schädel vieler Säugethiere . . . so gross
sind, dass man diese wie Schädel verschiedener species behandeln muss,
während in anderen Ordnungen (Rosores, Edentaten) die Schädel solche
Unterschiede nichtzeigen." In the past, failure to appreciate the large
amount of secondary sexual variation has resulted in erroneous
deductions as regards characters of certain geographic races and has
been the cause of some nomenclatural confusion, as for example, in
_Mustela frenata macrura_, where the female was named as a separate
species (_Mustela jelskii_).


Individual Variation

Individual variation is here considered to be the variation in one
species which can occur between offspring of a single pair of parents,
after variation ascribable to differences in age, sex, and season is
excluded. Individual variation, therefore, is a term here used in a
composite sense; it includes variations which probably represent
different genetic strains within certain populations and variations
induced within one generation by environmental factors.

In skulls of weasels, the individual variation in size is more than it
is in relative proportions. Hensel (_op. cit._) has stressed that
weasels, like other carnivores, produced "dwarfed" individuals more
than do herbivorous mammals. I cannot vouch for the accuracy of this
view, but can say that individual variation is not greater than in some
other fissiped carnivores. Impressions to the contrary probably result
largely from failure to recognize age-variation. When skulls of a large
series from any one locality are arranged first by sex, and under each
sex according to probable age on the basis of extension anteriorly of
the sagittal crest and of degree of postorbital constriction,
individual variation is seen to be less than a cursory examination,
even of only one sex, would suggest.

Study of a large series of one age of one sex of one species from one
locality shows that some parts, of the skull for example, vary more
than other parts. In illustration, among 22 male topotypes of _Mustela
frenata washingtoni_ the least interorbital breadth varied 25 per cent
(9.0 mm. to 12 mm.) whereas the length of the tooth-rows varied only
13.3 per cent (15.6 mm. to 18.0 mm.). In color the individual variation
definitely is more in areas of intergradation between subspecies than
in other areas. Details of one such instance of intergradation are
given in the account of _Mustela frenata spadix_.

Statements to the effect that there is much individual variation in the
color of weasels, were made mostly fifty years or so ago by writers who
had but few specimens from widely separated localities. Where marked
climatic differences exist between localities only a few miles apart,
marked differences occur in coloration of the weasels from the
different localities. Much of what formerly was mistaken for individual
variation now proves to be geographic variation. Individual variation
actually is of slight amount in comparison with that in mammals
generally. Differences in size and relative proportions of parts
usually are correlated with geographic differences in color. The color
does fade slightly in the period between molts. Also as a result of the
seasonal color change, in autumn along the upper margin of the Austral
Life-zone, some individuals become white whereas others become white on
only the underparts, the upper parts changing only to lighter brown.
Probably it would be correct to say that this variation was a
combination of seasonal and individual variation rather than either one
alone.

As might be supposed, individual variation is not the same in all
species or subspecies. For example, p2 is always absent in _Mustela
africana_ and always present in certain subspecies of _M. frenata_. In
some other subspecies of _M. frenata_, p2 is absent approximately as
often as present. In the writer's experience, when only a few specimens
are available for comparison, individual variation is more difficult to
distinguish from specific and subspecific (geographic) variation than
is age-variation or secondary sexual variation.

Among the larger series of specimens examined, only one instance of
what might be called a mutation in the old sense of a large, sudden
change, was detected. That was the loss of the second lower molar in
many (less than a third) of the specimens from Newfoundland. The six
instances of abnormal coloration described on pages 41 to 43, might be
regarded as mutations of large magnitude but no evidence was found of
repetition of an abnormality in any one population. Otherwise, in
every instance where plotted, the manifestations of a variation
arranged themselves about the mean in such a way as to form a smooth,
unimodal curve.


Seasonal Variation

When subspecific and specific variations are the objectives of study,
seasonal variation must be understood, in order to be excluded from
consideration, in the same way that variations ascribable to age, sex
and individualism must be understood in order to be excluded from
consideration. In weasels, change in color of the pelage is the
seasonal variation most important for the systematist to understand.
Other seasonal variations in the pelage are hairiness versus nakedness
of the pads of the feet, length of the pelage on the body, and possibly
the density of the pelage on the body. In the northern half of North
America, roughly speaking, seasonal change in color is so pronounced
(white in winter and brown in summer) as to be easily recognized. South
of this area, in the Austral and Sonoran life-zones, the color of the
winter pelage differs only slightly from that of the summer pelage. In
these more southern latitudes the winter pelage in almost all
subspecies is of lighter color than the summer pelage and has a smoky
suffusion. With material of the two seasons in hand for comparison,
close attention to the variation will permit the systematist to
recognize the difference in shade of brown as seasonal variation and
not geographic or specific variation. Farther south still, in the
Tropical Life-zone, seasonal difference in color was not detected in
the material studied. Seasonal change in color is discussed in the
section immediately following.


Variation in Coloration and Molt

In all American weasels (subgenus _Mustela_) the color, at least in
summer, is brown with more or less white or whitish on the underparts.
In one species, _Mustela africana_, there is a longitudinal stripe of
brown on the middle of the light-colored underparts; this stripe is
absent in each of the other three American species. Two species, _M.
erminea_ and _M. frenata_, always have a black tip on the tail. Of the
other two species, _M. africana_ lacks the black tip and _M. rixosa_
may or may not have a few black hairs in the tip of its tail. White or
light yellowish facial markings occur in subspecies of _M. frenata_
from the southwestern United Stated to Central America. Subspecies
having the most extensive light-colored facial markings have the
remainder of the upper part of the head black. In weasels without light
facial markings the upper parts of the head all are brown. In the two
species, _M. erminea_ and _M. frenata_, the extent to which the light
color of the underparts extends down the insides of the legs and out on
the underside of the tail, or the absence of light color on these
parts, is a matter of geographic variation. The same can be said for
_M. rixosa_ except that first its tail is unicolored and second
individual variation as well as geographic variation accounts for the
color pattern on the underparts and legs in animals from the
southeastern part of the range of the species.

The most remarkable feature of the coloration of weasels is the winter
whitening. This occurs in the northern part of North America in each of
the three species of weasels found on that continent. The black tip of
the tail in _M. erminea_ and _M. frenata_ remains black in winter. If
an individual of _M. rixosa_ has black hairs on the tip of its tail in
summer, there are thought to be black hairs there also in winter.
Otherwise the winter pelage is all white in northern areas in each of
the three species. In this white winter coat the animal is known as
ermine.

The underlying cause seems to be protective coloration. At any rate,
weasels are always white in winter if they are from areas where snow
lies on the ground all winter, every winter, or almost every winter;
and they are always brown if from areas where there is never, or
rarely, snow in winter. The changes in color are effected by molt, one
in autumn and one in spring. Animals that are brown in winter undergo
the same two molts as do those that are white in winter. The capacity
to acquire a white coat or a brown coat in winter is an hereditary
matter just as one man grows red hair and another grows black hair. In
the weasels, however, all individuals in the north turn white in winter
and if one that was born there is kept through successive winters in
the warmer south where there is no snow, he will still turn white each
winter. A weasel born in a southern area, where all are brown in
winter, molts into a brown (not white) winter coat even when kept in a
cold, snowy, northern area where native weasels of the same species all
turn white. Obviously, therefore, neither snow nor temperature is an
immediate cause and, as we have said, the color in winter is a matter
of heredity. The time of the molt, we now know, is determined by the
amount of light. When nights grow longer and days shorter, a point is
reached at which the lesser light received through the eyes causes the
pituitary gland to cease producing a gonadotropic hormone. Directly or
indirectly, the lack of this hormone stimulates molt and, probably
enzyme action, or the lack of it, causes the melanoblasts of the cells
in the hair follicle to be without pigment. Hence the hair grown from a
follicle under such conditions lacks pigment (melanin) and is white. In
spring, as the days grow longer and the nights shorter, the increasing
amount of light received day by day through the eyes stimulates the
pituitary gland to produce the gonadotropic hormone which directly or
indirectly, stimulates molt and, probably by enzyme action, the
melanoblasts are caused to be present in cells of the hair follicle and
the melanoblasts provide granules of melanin pigment which are
incorporated in cells of the growing hair. These granules of pigment
give the hair its color.

Evidence in support of this hypothesis is given below.

Along the Pacific Coast from British Columbia southward, _M. erminea_
(see fig. 25 on page 95) is brown in winter. This is an area where snow
rarely falls and the temperature in winter ordinarily is above
freezing. In the remaining part of the American range of this species
the temperature in winter is below freezing much of the time and snow
remains throughout the winter or for long periods. In this colder part
of the animal's range, only white coats occur in winter. _M. frenata_
likewise has a white coat in winter in the part of its geographic range
where snow and freezing temperatures prevail throughout most of the
winter and a brown coat in warmer, snowless areas to the southward and
along the Pacific Coast. The third species, _M. rixosa_, exhibits a
corresponding correlation between coat color and climate. On the
Asiatic continent, several species, including _M. erminea_, provide
parallel correlations and nowhere are there any exceptions for the
subgenus _Mustela_. These data are an important part of the material on
which we have based the induction that the underlying cause of seasonal
change in color is a need for protective coloration.

As regards molt, most naturalists who have written upon the subject
regard it as responsible for the change from the white winter coat to
the brown summer coat. However, the change from brown summer coat to
white winter coat has been thought by several writers to be effected by
change in coloration of the individual hairs. Among those holding this
opinion there may be cited Bell (1874:197) in reference to _Mustela
erminea_, and Coues (1877:123) in reference to American specimens to
which he applied the same name. More lately Hadwen (1929) has taken
this same view, and Gunn (1932) also discusses the possibility of the
hairs changing color. Bachman (1839:228-232), Macgillivary
(1843?:158), Audubon and Bachman (1851 (vol. 2):62), Schwalbe
(1893:538), Pearson _et al._ (1913:447), Miller (1930, 1931A), Hamilton
(1933:300) and Rothschild (1942), among others, have been inclined to
the opinion, or positively affirm, that the color change in autumn is
the result of a molt. The papers cited above contain, in turn,
references to many other printed accounts dealing with this question.

To my mind, it has not so far been demonstrated that the change in
color of weasels in autumn is accomplished without a molt. Also so far
as I am aware, no explanation has been given of how the pigment may
disappear from the hair of weasels. Metchnikoff's (1901:156) idea that
the senile whitening of the hair in man is accomplished by phagocytes
which remove the pigment granules would hardly seem to explain the
relatively sudden and complete autumnal change occurring in weasels.
Anyhow, Danforth (1925:108), and some other students have thought that
the action of these phagocytes was at most a factor of slight
importance in the whitening of hair. Whatever be the complete answer to
the question of how the weasel changes color in autumn, at least one
specimen of long-tailed weasel, which is in process of color change in
autumn, presents clear evidence of molt of the overhairs. This specimen
of _M. f. longicauda_ is no. 188408, U. S. Nat. Mus., taken on November
12, 1897, at Rapid City, South Dakota. Other specimens of _M. erminea_
which were taken in autumn similarly show molt to be in progress. For
these and other reasons, I am inclined to the opinion that the autumnal
change in color, like the one in spring, is effected by molt. During
the period of the autumnal color change, Noback (1935:27) had a captive
_M. f. noveboracensis_ and, each morning, found clumps of brown hair on
the floor of its cage; this was strong indication that molt was
responsible for the color change in this instance.

However, I freely admit that the evidence does not _prove_ that the
change from brown to white can be accomplished _only_ by molt; in the
present state of knowledge it would be unscientific to deny that the
change were possible of accomplishment by other means. Also, it is true
that the fifteen specimens before me of _Mustela frenata_, subspecies
included, in process of change from brown to white, with the exception
of the one from Rapid City, South Dakota, if taken individually, do
not, in macroscopic examination, show definite molt lines or other
absolutely convincing evidence of molt. However, these same specimens,
insofar as examined microscopically, do show overhairs all white, or
overhairs pigmented throughout. The lighter color of the proximal parts
of the overhairs in itself should not be accepted as evidence of color
change, for in the fresh summer pelage, the same condition exists.
Also, careful macroscopic examination suffices to show that in the
transitional pelage of autumn, the brown overhairs generally are longer
than the intermixed white overhairs.

Whether the underfur behaves in exactly the same way as the overhair, I
have not myself definitely ascertained, but I assume that the underfur
is molted twice each year, at least in the northern populations of
_Mustela frenata_ and in the other species of more northern
distribution. Schwalbe's (1893) work, including sectioning of the skin
and study of the hair follicles, led him to conclude that the underfur
was molted twice each year in _Mustela erminea_.

In _Mustela frenata noveboracensis_, _M. f. nevadensis_, and _M. f.
nigriauris_, measurements taken on adult males show the overhairs to be
longer in the winter pelage than in the summer pelage of specimens from
the same locality. For example, in _M. f. nigriauris_ from Berkeley,
California, the overhairs of the summer coat (July and August) average
8 millimeters in length on the hinder back and 7 mm. on the belly, but
average 9.5 mm. and 8 mm. respectively in January-taken specimens
possessing the full winter coat. At Ann Arbor, Michigan, in the summer
coat, the longest hairs on the hinder back average approximately 12
mm., and those on the belly, 9.5 mm., against 13 mm. and 9.5 mm.
respectively in winter. Although general observations initially led me
to believe that the black, terminal hairs of the tip of the tail are
longer in the winter pelage than in the summer pelage, actual
measurements fail to show a difference in length.

The change from one coat to the other in the long-tailed weasel has
been described among others by Miller (1930, 1931A), Hamilton (1933)
and Glover (1942) on the basis of captive specimens. In a general way,
the progress of the molt in their specimens agrees with that which I
have been able to make out from examination of skins taken in the wild.
There is, however, this difference: Their specimens show a more spotted
pattern when in process of hair-change than do specimens taken in the
wild. Probably the more or less unnatural conditions under which these
captive animals lived modified the normal progress of molt.

In wild-taken specimens of the species _Mustela frenata_, subspecies
included, the spring molt begins on the mid-dorsal line and proceeds
laterally, producing, at almost any given time, a relatively sharp
molt line separating the white winter hair from the incoming brown
summer coat. However, in autumn the change takes place first on the
belly, then on the sides, and finally makes its appearance over all the
upper parts at about the same time, with the result that the upper
parts have a salt-and-pepper appearance without at this time any
sharply defined molt lines. In general, the molt pattern can be said to
be reversed in the two seasons; in spring, it begins on the back and in
autumn, on the belly. The difference in spring and autumn color pattern
is better illustrated on plate 39 than by additional description.
Swanson and Fryklund (1935:123) have observed that the "spring molt
proceeds differently" than the fall one in _Mustela rixosa_, and
Barrett-Hamilton (1903:309) in commenting on the European hare (and the
stoat?) remarks, "In spring the moult, and with it the brown colour,
progresses in exactly the opposite order . . ." as compared with the
white color of autumn, which that particular writer thought resulted
from removal of pigment from the hairs rather than from molt.

The tail, excepting the black tip, lags in the molt in many instances,
with the result that, especially in spring, it may retain a few white
hairs as late as does the belly. In autumn it is less tardy and so far
as I have observed, becomes white at about the same time that the
general area of the back changes color. On the tail, the black tip
itself, as clearly shown in more than a score of specimens, is molted
at approximately the same time in autumn as is the pelage of the body.
However, the long black hairs, which appear in, say, November, appear
to increase in length until January. In spring, the long black hairs of
the tip of the tail seem not to be shed at the same time as the rest of
the winter pelage, but remain approximately six weeks longer and then
are replaced by long black hairs of the summer coat. At any rate, this
is the picture presented by a half dozen specimens of _M. f.
nevadensis_ and _M. f. longicauda_ which do show a spring molt to be in
progress on the black tip of the tail. Schwalbe similarly
(1893:536-537) has suggested that the black tip of the tail in _Mustela
erminea_ in spring is not molted until about two months after the
pelage on the rest of the body is changed. Schwalbe (_loc. cit._)
thinks also that in _M. erminea_ studied by him, the black tip of the
tail in autumn is replaced approximately one month in advance of the
pelage on the rest of the body. As indicated above, my specimens of
_Mustela frenata_, subspecies _longicauda_ and _nevadensis_, do not
show this discrepancy in autumn. I have considered the possibility that
the black tip of the tail, in some species of _Mustela_, is molted only
once while the remainder of the coat was undergoing two molts. My
inconclusive data lend but little support to this possibility.

The difference in pattern of color between specimens taken in autumn
and spring is known to some fur-trappers of my acquaintance who have
suggested that molt occurs in spring, whereas the individual hairs
change color in autumn. Reference to plate 39 will show how gross
comparisons might lead one to this erroneous explanation of the color
change.

As to time of molt: In eight subspecies of _Mustela frenata_, namely,
_noveboracensis_, _occisor_, _primulina_, _spadix_, _longicauda_,
_arizonensis_, _nevadensis_ and _effera_, material is available to
indicate that the autumnal molt begins in October and is completed in
November, and that the spring molt occurs in March or April. A
condensed list of specimens providing basis for this statement is as
follows:

     _M. f. noveboracensis_: 26 specimens in transitional pelage taken
     in autumn and 14 taken in spring; _M. f. occisor_: One topotype
     has acquired one-fifth of the winter pelage on October 22, 1896;
     _M. f. primulina_: 2 in November, one in March, and 2 in April are
     in process of change; _M. f. spadix_: 6 autumnal specimens and one
     in April show pelage change; _M. f. longicauda_: 7 autumnal
     specimens and one in April show pelage change; _M. f.
     arizonensis_: 12 specimens in autumn and 3 in spring are in
     process of molt; _M. f. effera_: One November-taken male has
     acquired four-fifths of the winter coat and another taken on April
     21 at Fort Rock, Oregon, is half finished with the spring molt.

It may be added that no marked difference in time of either autumnal or
spring molt is apparent as between the more northern and more southern
localities from which the mentioned specimens come. With more complete
material I would expect to find a difference in this regard.

The material of the other, more southern, subspecies of _Mustela
frenata_ has not been adequate to show the time of molting or the
number of molts which occur in one year.

Animals in the northern part of the range of _Mustela frenata_ acquire
a white winter coat, whereas those in the southern part acquire a brown
winter coat, and in an intervening area the winter coat may be either
brown or white. By plotting on a map the localities of capture of all
specimens examined in the winter coat, it was possible to outline this
intervening area as shown in figure 10 on page 37. However, Dearborn
(1932:36) shows that in Michigan some animals have a brown coat in
winter at places farther north than figure 10 shows to be the case.
Hamilton's (1933-306) map for New York shows the same to be true in
that state. Accordingly, the boundaries of the area shown in figure 10,
in which both brown and white long-tailed weasels occur in winter, are
known to be only approximate; with full information available the belt
would be represented as wider.

[Illustration: FIG. 10. Map showing the region (in black) where both
the brown and white winter pelage is found in the long-tailed weasel,
_Mustela frenata_.]

Hamilton (1933:302) has pointed out that "Where half of the weasels
remain brown, these brown winter specimens are always males." The
results of my own examination of specimens not studied by Hamilton, in
a general way provide confirmatory data. More exactly, my examination
reveals that at the most northern localities where brown specimens
occur, only males are in this coat. In explanation, it may be said that
in plotting on a map localities of capture of specimens in the winter
coat, thirteen places were found where both sexes were represented and
where both brown and white winter coats were found. With the two sexes,
it is theoretically possible to have nine different combinations of
coat color. With males all brown, there might occur females (1) all
brown, (2) all white, or (3) some brown and some white. In addition to
these three combinations, we might have three more by finding the
mentioned types of female coat color repeated where all males are
white, and three more, or nine in all, by substituting a population of
males some of which were brown and some of which were white. Seven of
these possible combinations actually were found. The two combinations
not found were all white males with all brown females, and all white
males with females both brown and white. In the three instances where
the males all were brown and the females all were white, the localities
of capture were in the northern part of the variable area. This
indicates that where the brown winter coat occurs at northern
localities, the brown individuals are all males. Farther south, of
course, the females, too, acquire the brown winter coat.

Stated in another way, there is a broad belt across North America from
the Atlantic to the Pacific in which males of _Mustela frenata_ at any
one locality may be either brown or white in winter. Inside this broad
belt there is a narrower one, approximately half as wide, in which
females at any one locality may be either brown or white.

In support of the idea that color of the winter coat is an hereditary
matter and that it is not dependent on temperature, the following
evidence derived from my transplanting specimens of _Mustela frenata_
supports the idea that color of the winter pelage is dependent on
heredity and not on temperature or snowfall.

A male captured on June 24, 1937, in the brown summer coat in Salt Lake
City, Utah, was received by me at Berkeley, California, five days later
and kept in captivity almost six months. On November 17, 1937, half the
pelage was white and on December 27, 1937, when next examined, the
animal was in the full, white, winter coat as it was on January 25,
1938, when it died. Native weasels all turn white in winter in Salt
Lake City, but in Berkeley native weasels always are brown in winter.

A juvenile or young animal, a male, captured in May, 1936, at
Lafayette, Contra Costa County, California, was kept there until August
13, 1936, when transferred to Calneva at the north end of Lake Tahoe,
California. The weasel was kept at Calneva until its death on December
23, 1937. In both the winter of 1936-'37 and in that of 1937-'38, the
winter coat was brown as in animals from its place of origin (Contra
Costa County) and unlike weasels of the Tahoe region nearly all of
which turn white in winter.

Two females, each approximately two months old, captured on May 1,
1936, at James Landing, 4 miles northwest of San Pablo, Contra Costa
County, California, were kept in Berkeley, California, until August 13,
1936, when they were transferred to the mouth of Blackwood Creek, on
the west side of Lake Tahoe, California. On October 25, 1936, both
weasels escaped. On December 25, 1936, the headless body of one of
these was found approximately 300 yards south of the mouth of Blackwood
Creek. The animal had been dead at most a few days when found and was
in the brown winter coat. At the place of its origin all weasels are
brown in winter but at the mouth of Blackwood Creek only 2 of 60
weasels caught there in the winter coat were brown; the other 58 were
white. The headless weasel was identified, as one of the two formerly
in captivity, by means of certain short toes, the ends of which had
been clipped off when the animal was a captive. No trace of the second
female was found.

A female of unknown age, in white winter pelage, captured 4 miles
southeast of Tahoe City, California, and kept there until April 3,
1937, on which date it was brought to Berkeley, California, molted to
brown in the spring. The first signs of the brown coat were noted on
April 14. On May 24 or 25 she gave birth to 4 young which lived less
than ten days. In the following winter this animal acquired a white
coat. As previously noted, weasels native to the Berkeley area, where
this female was kept, have brown coats in winter.

The weasels were in every instance kept in cages out-of-doors. The
sides of the cages were open to the elements. A nest box in each cage
provided shelter. All were of the species _Mustela frenata_.

The significant results, it seemed to me, were that the winter coat was
the kind found in the area where the weasel originated instead of the
kind found in weasels native to the areas in which the specimens were
held in captivity.

That the time of molt is determined by the amount of light has clearly
been shown by Bissonnette (1944:223) for American weasels of the two
species _Mustela erminea_ and _M. frenata_. In his words (_op.
cit._:246) "Reducing the daily periods of light induced molting and
regrowth of new fur. . . . In the Bonaparte weasels [_Mustela
erminea_], white replaced brown. . . . Increasing daily light-periods
caused molting and change to dark brown. . . . Incomplete molts in both
directions (toward white or toward brown) were produced as a result of
early reversal of increase or decrease of daily light-time. . . . That
this stimulus is received through the eyes and acts through the
anterior pituitary gland is indicated by Bissonnette's [1935:159]
studies on ferrets, a nearly related animal. That the thyroids and
sex-glands are not essential is at least suggested . . . by Lyman's
(1942) study on the varying hare [_Lepus americanus_]." It can be added
that Lyman (1943:451) demonstrated in _Lepus americanus_ that the
effect of light is received through the eyes. He demonstrated this by
masking the animals. To Wright (1942B:109) who studied the two American
weasels, _M. erminea_ and _M. frenata_, it seemed likely that the
pituitary produced or released gonadotropic hormone at about the time
of the spring molt and that this molt and the spring changes in the
reproductive tracts of the weasels might be caused by a stimulus from a
common source. Later, Wright (1950:130) injected a gonadotropic hormone
into long-tailed weasels which had recently acquired their white winter
pelage and thereby caused them to lose the white pelage and acquire the
brown pelage. It is Lyman (1943:450) who says, in relation to _Lepus
americanus_, "When in the physiologically white condition, the
melanoblasts of the regenerating guard-and pile-hair follicles contain
no melanin-forming enzyme (dopa-oxidase), which may be the reason for
the lack of pigment." Schwalbe (1893) by sectioning the skin and
microscopically examining the hair-follicles of _M. erminea_ learned
that the basal cells producing hairs lacked pigment granules in autumn
when the European ermine (_M. erminea_) was acquiring its white winter
coat and that the cells contained granules of pigment in spring when,
as we know, the granules are incorporated in the growing hair and give
it its color.

The above material, then, is basis for the account on pages 31 and 32
of what causes the weasel of northern areas to have a white coat in
winter. The discerning student will instantly perceive that although
some parts of the account on pages 31 and 32 are precisely accurate,
other parts are the result of inferences which need to be proved. More
careful work of the kind that Schwalbe (1893) and Wright (1942B) did is
needed. The account on pages 31 and 32 is merely the best that can be
given with the information now available.

Many writers have commented on the yellowish color, sometimes with a
greenish tinge, found on the fur of weasels in the white winter coat.
The stain is more often found on the tail and hinder-parts of the body
than elsewhere. Possibly, partly on this account, some have ascribed
this color to the smearing of the fur with urine. Still others have
thought it resulted from the smearing of the fur with secretions from
the anal scent glands. Schumacher (1928) takes this point of view, and
while it may be that he has not proved his point, still his conclusions
fit the known facts and seem sound to me. Schumacher points out that
the same soiling of the fur is present in summer as well as in winter,
but that on the summer pelage the stain can be detected only on the
light-colored underparts. It is from this point of view that he
criticizes the systematic worth of white versus yellowish-white
underparts in the summer pelage of geographic races of _Mustela
erminea_ and _Mustela nivalis_. Although in the long-tailed weasels
(_Mustela frenata_) the underparts of all the races are pigmented with
some form of red, orange or yellow, it seems probable to me that the
additional color resulting from the soiling effect of this glandular
secretion explains the greater variation, found at a single locality,
in the color of underparts than of upper parts in the summer pelage.

I have neither seen nor heard of a black weasel in any part of the New
World or of the Old World. I have found only one albino among American
specimens. It is an adult female, no. 121424, American Museum of
Natural History, of _Mustela erminea richardsonii_, taken on August 30,
1935, at Hot Springs, Northwest Territory. This place, I am told by G.
G. Goodwin who obtained the animal, is on the "Nahanni River where the
rugged mountain ridges rise abruptly from the low mud flat lands,
latitude 61, longitude 125." The shortness and coarseness of the hair
corresponds to that of the summer pelage and not winter pelage. The
pelage is everywhere white, even the tip of the tail. True, all except
the nape and top and sides of the head has a faint yellowish-green
tinge which has been supposed to result from staining by secretion of
the anal scent glands but there is no pigment in the hair as in
erythristic specimens. From the Old World, Farurick (1873:17) has
recorded what he regards as an albino of _Mustela vulgaris_ since it
had no black hairs on the tip of its tail. Flintoff (1935:228, 229)
records what may have been an albino _Mustela vulgaris_ from Yorkshire
and an albino _M. erminea_ from an unstated locality. Jäckel (1873:459)
mentions specimens of _Mustela erminea_ and _Mustela vulgaris_, which
were partly "albinistic" or "erythristic." Among the American specimens
of _M. erminea_ I have not recorded any which appeared to be either
partly or wholly erythristic or only partly albinistic. Among the 1550
skins of _M. frenata_ which were in summer pelage or brown winter
pelage, five, described below, show marked abnormalities in color.

Two of these five are partly albinistic. One is an adult male, no.
223880, U. S. Nat. Mus., from Billy's Island, Okefinokee Swamp,
Georgia, which has the nose as well as the area between the eyes white.
Also there is a tuft of white hairs at the anterodorsal margin of each
ear, scattering white hairs suggesting a postorbital bar on each side
of the head, and a patch of white hairs on the mid-dorsal line behind
the ears. Markings of this kind are not abnormal in _M. f. peninsulae_,
the subspecies adjoining on the south, except for the white nose which
clearly is an instance of partial albinism. The second specimen is a
subadult male, of _M. f. noveboracensis_, no. 177679, U. S. Nat. Mus.,
in process of acquiring the brown winter coat, taken on November 27,
1911, at Gaylordsville, Connecticut. It has white markings on the nose,
on the right side of the neck, on the right hind foot and right
forefoot, and on the tip of the tail. The white area of the nose on the
left side extends back to the eye, but on the right side barely
encircles the nose-pad. On the right side of the neck, all that area
between the foreleg and ear is white from the mid-dorsal line
(including 7 or 8 millimeters to the left of the mid-dorsal line) down
to the throat, which is white as it is also in normal individuals. The
toes of the right hind foot are more extensively white than in normal
specimens of _noveboracensis_, and all of the right forefoot as well as
the wrist is white. The tail is of striking appearance because of its
tricolor pattern. The proximal part is of the normal brown color. The
black terminal part commences proximally at the usual place, but the
distal 11 millimeters of the fleshy part of the tail bear only pure
white hairs producing a terminal white pencil 35 millimeters long.

The three other specimens abnormally colored are erythristic
individuals. An adult male of _M. f. latirostra_, no. 7574, coll. D. R.
Dickey, taken on April 14, 1918, at Covina, Los Angeles County,
California, has the color of the upper parts greatly restricted, and,
in addition, has spots and blotches of the color of the underparts
distributed over the back and rump. A spot of this same color occurs
above each ear. Incidentally, this and other subspecies of _Mustela
frenata_ from the Pacific Coast of North America obviously have the
factor for erythrism operating over a larger part of the body than it
does in _M. erminea_ or than in _M. f. noveboracensis_, where the
underparts sometimes are white. In _M. f. latirostra_ and in other
subspecies from the Pacific Coast the light color of the underparts
always is tinged with this reddish color.

Another erythristic specimen is a young male of _M. f. nevadensis_, no.
23493, U. S. Nat. Mus., taken on August 6, 1890, at Birch Creek, Idaho.
It has all of each foreleg, the axillary regions, and a saddle-shaped
area over the shoulders of the same buff-yellow color as the
underparts.

The third erythristic specimen is a subadult female, of _M. f.
oregonensis_, no. 47149, Mus. Vert. Zoöl., taken on December 20, 1930,
at Carlotta, Humboldt County, California. This specimen appears to be
white and initially was thought to be merely an individual in the white
winter coat. Closer examination, however, shows that it has a light
wash of ochraceous or faint reddish color. Also, other specimens taken
in winter at Carlotta show that weasels there do not acquire a white
winter coat. The only normally brown area is approximately three
millimeters in diameter at the anterodorsal margin of the pinna of the
right ear. The tip of the tail is black as in a normal specimen. The
specimen in question is actually pure white only on top of the head
from a short distance behind the ears on over the forehead nearly to
the eyes, and on the inside of the ears. In a normally colored animal
this area is the dark area of the head. In this freak, the other parts
of the head, which, in individuals of normal coloration are the white
or light orange facial markings, have the reddish cast of the remainder
of the body, although the color is less intense than on the back. The
collector noted that the specimen had eyes of normal color. A possible
explanation for the coloration of this specimen is that this species
has three factors for color, one for the black tail tip, one for the
reddish color, and a third, missing in the specimen in question, for
the blackish brown.

For some more exact knowledge concerning this erythristic type of
coloration, we are indebted to Pitt (1921:99), who describes a
population of polecats, _Mustela putorius_, in Cardiganshire, England,
in which this erythristic variation is maintained in a state of nature.
In ferrets, _Mustela furo_, Pitt (_op. cit._:114) notes that ". . .
erythrism is certainly dependent on a Mendelian factor, being dominant
to albinism and recessive to the black-brown coloration. Both in the
ferret and polecat, erythrism seems to be correlated with increased
size, and certainly in the ferret is usually accompanied by a quick
temper and general increase in vitality."


Variations of Taxonomic Worth

Variations of taxonomic worth usually are referred to as characters.
For example, shortness of the tympanic bulla is a character, and the
opposite condition, long tympanic bulla, is another character. Specific
variations, that is to say specific characters, are provided by the
color-pattern, length of tail, number of premolar teeth, shape of the
tympanic bullae, and length of the braincase in relation to the length
of the tooth-bearing parts of the skull. Subspecific characters are
provided by color-pattern, color itself, size as measured by weight of
the animal, and its linear measurements, size of the skull, and size
and shape of parts of the skull. The characters distinguishing
subspecies from one another are not of a different nature from those
distinguishing species from one another.

Given any one of the above structural features, say, dorsal outline of
the skull, several characters may be provided by it. For example,
weasels of the species _Mustela frenata_ have the dorsal outline of the
skull convex in southern Louisiana, straight in Missouri and concave in
North Dakota, thus providing three characters. This is geographic
variation. These variations, characters in zoölogical parlance, when
plotted on maps, reveal the geographic occurrence of, say, the convex
shape of the skull. In combination with other characters, for example,
dark color and short tail, basis is provided for recognizing a
subspecies, in this instance _Mustela frenata arthuri_ of Louisiana.
Because the change from convex to flat skull takes place geographically
at about the same place (in eastern Texas) as does the change from
short tail to long tail, and the change from dark color to light color,
it is easy to draw a line there marking the western geographic limit of
occurrence of the _M. f. arthuri_. This same line marks also the
eastern margin of the geographic range of the subspecies _Mustela
frenata frenata_, the subspecies next adjacent to the westward. On this
line and for several miles to either side of it weasels show varying
combinations of these three characters or an intermediate condition as
regards one or more of the characters, or both. For example, from a
locality in eastern Texas a weasel may have (1) a facial pattern
exactly intermediate between that of the unicolored face of _arthuri_
and that of the bicolored face of _frenata_, (2) the long tail of
_frenata_ and (3) the convex skull of _arthuri_. In the sum of its
characters this specimen is exactly intermediate between typical
_arthuri_ and typical _frenata_. Another specimen from the same place
may differ from the first specimen only in having the tail slightly
shorter. The total "score" for the two specimens is, therefore, by a
very slight margin in favor of _arthuri_. Let us suppose that we obtain
a third specimen from the same place and that it has the face marked
like that of _arthuri_ but the tail fully as long, and the skull as
lacking in dorsal convexity, as in _frenata_. Now the score is
definitely for _frenata_. For convenience of handling, the population
is referred to _frenata_, providing that the average of specimens from
a nearby locality to the westward is not in favor of _arthuri_. In
event the average of specimens from a locality next adjacent to the
westward is in favor of _M. f. arthuri_, the total evidence from the
two localities may be weighed together and appropriate decision as to
subspecific status of weasels from the area is made according to what
the average is for the area as a whole.

The three individual animals of an intermediate sort are ordinarily
termed _intergrades_. This implies that their characters are the result
of mixed parentage--perhaps a female of _M. f. arthuri_ and a male of
_M. f. frenata_ but probably each parent itself was an intergrade and
the offspring, of which we examined three, owe their characters to
reproductive processes operating in obedience to Mendelian laws of
inheritance.

The two kinds of animals, _Mustela frenata arthuri_ and _Mustela
frenata frenata_, are identified as subspecies because of the
intergradation between them. If at this and all other places where the
geographic ranges of _arthuri_ and _frenata_ met there was no
crossbreeding (no intergrades), the two kinds would be treated as
distinct species. Intergradation, and the lack of it, are accepted as
the criteria of subspecies and species, respectively.

These criteria suffice for animals, in this instance weasels, which
have a continuous geographic distribution. Some kinds of weasels are
confined to islands, as for example the islands off the coast of Alaska
and British Columbia. Because weasels are land animals, crossbreeding
in nature between the weasels of two islands is, of course, impossible.
A modified test (used in the study here reported upon) in deciding on
specific versus subspecific status in these instances can be made as
follows: On the adjacent mainland, ascertain the degree of difference
between two subspecies whose geographic ranges meet (for example, _M.
e. richardsonii_ and _M. e. alascensis_). Next ascertain the degree of
difference between the insular kind of animal and the kind on the
mainland. If the degree of difference is greater when the insular kind
is compared than when only the kinds of the mainland are compared, the
insular kind is to be regarded as a species. If the degree of
difference is no greater between the insular kind and the mainland kind
than it is between the two adjacent mainland kinds, the insular kind is
to be regarded as a subspecies. In short, for insular kinds, the
criterion is degree of difference, with the limitation of geographic
adjacency, rather than intergradation.

The geographic variation (subspecific characters) found could be spoken
of as two kinds: First, there is the variation which is expressed in a
general trend for a long distance, producing, in general, a cline of
even slope; and second, that of inconstant trend in any one direction.
In his "The Rabbits of North America" Nelson (1909:34-35) has commented
on the latter type of variation as follows: "While studying series of
specimens from all parts of the vast range occupied by the geographic
races of such species as _Sylvilagus floridanus_ and _S. auduboni_, I
have been impressed with evidences of fluctuation of both external and
skull characters. These fluctuations are somewhat wavelike in character
and rise to central points of extreme development and then sink away to
intermediate borders beyond which new waves rise. Where the waves of
differentiation are pronounced they mark recognizable geographic races.
Within the area covered by the larger or geographically broader waves
of differentiation (recognized as of subspecific value), smaller waves
of differentiation are included, which may represent local variations
in intensity of characters of the subspecies, or these characters may
diminish and the variation tend in other directions, sometimes even
closely reproducing the characters of another subspecies occupying a
distinct area." In _Mustela frenata_, much of the geographic variation
at first inspection appears to be of this nature. Closer scrutiny,
however, reveals that the repetition, at geographic intervals, of
several features of color and structure are closely correlated with
environmental features which are repeated only at these same places.

In _Mustela erminea_, much of the variation is of the first kind,
namely, that which can be expressed as long clines of relatively even
slope. As several authors have said, zoölogical classification based on
this kind of variation is like dividing the spectrum and depends
largely upon the standards set, for, theoretically, the possibilities
of subdivision are unlimited. Actually, however, none of the clines has
an even slope and the possibilities for subdivision therefore are
limited. Also, when several features are used, instead of only one
feature, the classification is more satisfactory even if the basis is
more complex.

Some features of structure which provide subspecific characters are
mentioned below.

Total length, of males, ranges from 598 to 360 mm. in _M. frenata_ and
from 336 to 228 mm. in _M. erminea_. There is no cline of sustained
slope in _M. frenata_ but in _M. erminea_ there is a progressive
decrease in total length from north to south.

Length of tail varies from as little as a half to as much as
seven-tenths of the length of the head and body in _M. frenata_, the
subspecies _neomexicana_ having the long tail and the two subspecies
_arthuri_ and _primulina_ having short tails. The geographic ranges of
_primulina_ and _neomexicana_ are contiguous. In _M. erminea_ there is
likewise no variation of a clinal nature in length of tail and
furthermore the variation is much less than in _M. frenata_.

In length of hind foot, which in males varies from 49 mm. in northern
populations of _M. erminea_ to 28 mm. in southern populations, the same
cline is seen as in the total length of animals of this species. In _M.
frenata_, however, there are several decreases and increases along any
straight line which can be drawn through the geographic range of the
species. The range of variation in males is 41 mm. (_M. f.
arizonensis_) to 59 mm. (_M. f. macrophonius_).

Weight of the entire animal is an excellent measure of size but weights
are unavailable for many subspecies. In _M. frenata_, the two
subspecies _texensis_ and _macrophonius_ probably are the heaviest and
_effera_, _arizonensis_ and _helleri_ probably are the lightest.
Geographically the variation in weight behaves in approximately the
same way as does the measurement of total length. In _M. erminea_ the
variation in weight of males is from 206 grams in northern animals to
58 grams in southernmost populations, there being a relatively constant
gradient geographically.

Degree of hairiness of the foot-soles in _M. frenata_ clearly is linked
with the temperature; in regions of high average temperature the
hairiness is least and in regions of low average temperature it is
most. The decrease in hairiness is accomplished in two ways, namely,
smaller breadth and decreased length of individual hairs and decrease
in number of hairs on a given area of dermal surface. This correlation
holds throughout the entire north to south range of the species.
Corresponding differences are found on the same latitude where
topographic diversity in an east to west direction produces northern
conditions at high altitudes and southern conditions at low altitudes.
The conclusion seems unavoidable that climate, directly or indirectly,
determines the degree of hairiness. Less careful observations were made
on the hairiness of the soles of the feet in other species but it is
clear that the northern species _M. erminea_ has the most hair on the
foot-soles and that _M. africana_, the tropical weasel, has the least.
In this regard, _M. frenata_ is intermediate as it is also in
geographic position.

[Illustration: FIGS. 11-15. Dorsal views of adult skulls of each sex of
five subspecies of the ermine, _Mustela erminea_, to show secondary
sexual variation and geographic variation in size of the skull. Males
on the left and females on the right. All × 1.

Note especially the geographic variation in decreasing size of the
skull from north to south in each sex, and that the secondary sexual
variation in size of skull is less in ermines with small skulls than in
those with large skulls.]

[Illustration: FIG. 16. Map showing the localities where the skulls,
represented in figures 11-15, were obtained.]

The maximum length of facial and carpal vibrissae is attained in _M.
erminea_ in the far north. In weasels from north of the Arctic Circle
the longest facial vibrissae extend posteriorly beyond the posterior
border of the ear. In the tropical weasel, _M. africana_, the facial
vibrissae do not extend posteriorly beyond the ear and the carpal
vibrissae are not so long as the distance between their bases and the
apical pad of the first digit. The correlation of long vibrissae with
low temperature, is mentioned here merely because length and density of
pelage were under consideration.

The most obvious and most exact correlation between change in climate
and change in the animal is furnished by color. This is well shown in
the one species, _Mustela frenata_, to which the following remarks
apply unless indication is given to the contrary. The color of the
upper parts varies from bay (blackish brown) in _M. f. panamensis_ to
buckthorn brown (light brown) in _M. f. neomexicana_. The color of the
head varies from solid brown (white chin excepted) to contrasting black
and white markings.

Dark color of the upper parts is associated with a large area of this
color; the enlargement of this area is at the expense of the area of
light color on the underparts. In the weasels of darkest color the
upper parts occupy four-fifths of the circumference of the body (as
measured in the anterior lumbar region) but in the lightest-colored
weasels the upper parts comprise only two-thirds of the total
circumference. In these light-colored animals the color of the
underparts extends onto the underside of the tail and down the insides
of the legs and over the feet whereas in the animals with the darkest
upper parts the entire tail, feet, and legs below the knees ordinarily
are of the same dark color as the upper parts. The length of the black
tip on the tail varies inversely with the length of the tail, probably
because the lightest-colored weasel has the longest tail. In some
subspecies the black brush is almost half as long as the tail-vertebrae
but in others is less than a fourth as long as the tail-vertebrae.

The extent of the color of the head, as well as the intensity of the
color there, varies markedly and is correlated with climatic
conditions. The extent and intensity of this dark color is greater in
weasels inhabiting regions of heavy rainfall than in those inhabiting
regions of sparse rainfall. Considering the geographic range of each
subspecies of _Mustela frenata_, that of _M. f. panamensis_ has the
maximum of rainfall. Reference to the colored plate (1) will show that
in _M. f. panamensis_ (2) the black of the head is extended over all of
the upper parts. _M. f. macrura_ (1) of Perú, to the southward, is from
an area of lesser rainfall and is correspondingly lighter colored.
Returning to _panamensis_ (2) as a starting point and proceeding
northward to the range of _nicaraguae_ (3), which also has lesser
rainfall, thence another step northward to Guatamala, which has still
less rainfall, the weasel there, _M. f. goldmani_ (4) has the black
extending posteriorly only to the shoulders. _M. f. leucoparia_ (5)
from Michoacán, and _M. f. frenata_ (6) from Tamaulipas are from
progressively more northern and also progressively drier regions. In
_M. f. frenata_ (6) the dark color extends posteriorly only to the ears
and is blackish rather than black. In _M. f. neomexicana_ (7) of the
extremely arid parts of Durango, Arizona, and New Mexico the dark
marking of the head is confined to a brown spot on the nose. Its
geographic range is the most arid of those of all of the subspecies.
The contrast between _neomexicana_ (7) and _panamensis_ (2) illustrates
the great range of geographic variation in color which occurs in the
one species. Continuing from the geographic range of _neomexicana_
(specimen from Safford, Arizona) northwesterly 480 miles to Riverside,
California (see 8, _latirostra_), 430 miles north to Point Reyes,
California (see 9, _munda_), and finally 570 miles north to Tillamook,
Oregon (see 10, _altifrontalis_), each place with more rainfall than
the one farther south, another correlation of increasingly dark
coloration with increasing amount of rainfall is illustrated.

This geographic variation, it should be remembered, is all within one
species. It is the more significant still when we remember that the
same correlation, with never an exception, occurs at hundreds of places
within the geographic range of the species. A particular feature of
climate, namely rainfall, and possibly therefore humidity, is concerned
in this correlation. The same correlation, heavy rainfall and dark
color, is shown also in the other species of North American weasels.
The conclusion is unavoidable that climate, directly or indirectly,
determines or influences the color of weasels.

The light facial markings appear in American weasels in two separate
geographic areas. One is the southwestern United States, México and
northern Central America. The second area is in the same latitude, in
Florida and adjoining parts of Georgia and Alabama. In the western
weasels the markings are white south of latitude 32° N. North of this
latitude, the facial markings, if at all extensive, usually are of the
same yellowish color as the underparts of the body. Weasels of southern
California and its interior valley usually have these yellowish instead
of white facial markings. The light facial markings, in this instance,
white markings, attain their maximum extent in _M. f. leucoparia_ of
the southwestern margin of the tableland of México, at latitude 19° N.
A gradual decrease in area of the light facial markings occurs both to
the north and south; they disappear at 10° N in _M. f. costaricensis_
and at 35° N at approximately the southern limits of range of _M. f.
arizonensis_ and _M. f. nevadensis_. In the mild climate of California
the light (yellowish) facial markings are found at still higher
latitudes. These light facial markings crop up as vestiginal remnants,
consisting of a few white hairs, in some individuals of nearly all
races of weasels.

In certain parts of the skull there are trends, in size and shape,
which continue for long distances geographically. In other words,
clines can be recognized. Changes in size and shape in some other parts
of the skull are wavelike; change toward narrower rostrum, for example,
is not progressive in a given geographic direction for any great
distance. Length of the upper tooth-rows and zygomatic breadth, when
expressed as percentages of the basilar length, and also the actual
length of individual teeth vary geographically in the same wavelike
fashion as does the width of the rostrum.

Size of the skull, on the other hand, shows a sustained trend for a
long distance; it becomes progressively smaller from the southern
United States southward to Columbia, South America. This clinal
variation can be demonstrated by plotting on a graph, the basilar
length, the zygomatic breadth, or the weight of the skull. Beginning at
Mérida, Venezuela, and proceeding southward to increasing elevations in
the mountains of South America, there is a reversal of the direction of
the variation in this cline; weight of skull, for example, increases to
the southward from Mérida for a considerable distance. A cline of
decreasing width of the postorbital constriction of the skull is
evident from Panamá north into Texas.

Variations in the tympanic bullae provide many characters useful in
distinguishing weasels from different localities. Most of these
characters have to do with degree of inflation of the bullae.
Indirectly correlated with degree of inflation is first the extent of
removal of the anterior margin of the bulla from the glenoid fossa and
foramen ovale, and second the form (convex, flat, or concave) of the
part of the squamosal bone between the foramen ovale and the anterior
margin of the tympanic bulla. As one proceeds southward from, say,
southwestern Kansas through the geographic range of the species
_Mustela frenata_, there is a progressive deflation of the bulla, an
increase in length of the space between its anterior margin and the
foramen ovale, and the floor of the braincase in front of the bulla
changes from ventrally concave to ventrally convex. (See figs. _e_ and
_h_ of pl. 24 and figs, _e_ and _f_ of pl. 27.)

One extreme of this variation in bulla is shown in _Mustela frenata
neomexicana_ (fig. _e_ of pl. 24), in which the anterior margin of the
bulla (viewed from the ventral side) rises vertically from the floor of
the braincase to form a 90-degree angle. The other extreme, the
uninflated bulla, is in _Mustela frenata panamensis_ (fig. _e_ of pl.
27), in which the anterior margin of the bulla is not raised above the
floor of the braincase. This variation is remarkable because it occurs
within a single species. Otherwise, in the family Mustelidae,
differences in the tympanic bullae as great as that between the two
subspecies _M. f. neomexicana_ and _M. f. panamensis_, occur only
between genera. The need for caution in inferring the limits of
variation for a particular structure in one species or genus, on the
basis of variation in another group, is therefore obvious.

Speaking now of full species, the most inflated tympanic bullae in
American weasels are in _Mustela frenata_, and more restrictedly in
those subspecies of it which occur in the temperate region. Subspecies
of _M. frenata_ in Central and South America, as already noted, have
less inflated bullae. The tropical weasel, _Mustela africana_, of the
Amazon drainage of South America has the bullae still less inflated
(see fig. _i_ of pl. 39 and fig. _f_ of pl. 40). The bullae are less
inflated even than in the mink, subgenus _Lutreola_. In _M. africana_
the cleidomastoideus, omotrachelian, levator scapulae, and rhomboideus
profundus muscles take origin from a fossa on the mastoid bone, whereas
in the forms with greatly inflated bullae these muscles take origin
from a raised ridge or tubercle. Using _Mustela frenata_ of the
temperate region as a starting point and proceeding northward, a
reduction in inflation of the tympanic bulla is seen also in that
direction in that _Mustela erminea_ has less inflated bullae. The
bullae are less inflated in southern than in far northern (arctic)
populations of _Mustela erminea_. In _erminea_ the lesser inflation is
real enough but at the same time there appears to be less inflation
than actually exists, for the squamosal floor of the braincase is
"pushed down." This places the anterior end of the tympanic bulla
farther in the braincase than it otherwise would be. Although the
anterior end of the bulla is flattened to the extent that it resembles
the sharp edge of a splitting-wedge, inspection of the lateral and
medial edges shows that in its central part the bulla is more inflated
than it is in the weasels of Central and South America.

For reasons set forth later, _M. erminea_ is judged to resemble the
ancestral stem form more closely than does any one of the other three
American species of weasels. If this judgment is correct, the shape of
the tympanic bullae of the American weasels may be explained as
follows: In the subspecies of _Mustela frenata_ of the temperate
regions of North America the bullae have most nearly been pushed out of
the braincase and at the same time have undergone some enlargement. The
subspecies of this same species in Central and South America represent
an earlier stage in the evolution of American weasels and retain less
inflated bullae--less inflated even than those of the southern
subspecies of _erminea_. _M. africana_ probably separated from the stem
form at a still earlier time if we may judge by the lesser inflation of
its tympanic bullae. There are other reasons for thinking that
_africana_ separated from the stem form earlier than _M. frenata_ did.
During the time that elapsed since the separation of _M. frenata_ from
the stem form, the tympanic bullae of _M. erminea_ probably increased
slightly in size, as probably also did the brain but without shoving
the auditory complex forward from its former position.



DISTRIBUTION AND SPECIATION


Weasels of the subgenus _Mustela_ are known from the Pleistocene but
not from deposits laid down at an earlier time (see page 10). The
Pleistocene weasels from Rancho La Brea of southern California and from
Potter Creek Cave and Samwel Cave, both of northern California, are
subspecifically indistinguishable from the weasels living in those same
localities today. The other notable occurrence of weasels in the
Pleistocene is in the Conard Fissure of Arkansas. Brown (1908:181, 182,
pl. 17) names two kinds from the Fissure. One is an extinct subspecies
(_Mustela frenata gracilis_) possibly of the species which occurs in
the same region today and the other, _Mustela erminea? angustidens_,
is an extinct subspecies of a species which occurs only farther north
today. _M. erminea_ came south, probably in front of one of the ice
sheets, as did several other species of American mammals, now of more
northern distribution, that left their remains in Conard Fissure.
_Mustela rixosa_ is not recorded as a fossil in America although it is
known from the "Diluvial" deposits of the Old World; see Woldrich
(1884:1000), who employs the name "_Foetorius minutus_ n. sp.," and see
also Zimmerman (1943:295-296).

The ermine, _Mustela erminea_, is the most generalized of the full
species. For example, the number of teeth is as large as in any other
species and greater than in certain species. The teeth are
sharp-pointed, uncrowded, and individually less specialized than in any
other American weasel. M1 has the inner half, or lobe, of approximately
the same size as the outer lobe instead of much larger than the outer
lobe (the outer lobe is the larger in several other species). The
tympanic bullae are less inflated and less protruded from the
braincase. The skull is rounded, and has no marked crests and ridges
whereas the skulls of the other species are more pronouncedly modeled
and sculptured. Therefore, it is possible to think of these other
species as derived from _M. erminea_. A derivation in the reverse
direction would be more difficult. From the foot soles of an ermine, or
a weasel closely resembling an ermine, the more complex soles of
_Mustela africana_ could have been derived by a decrease in hairiness,
although it would be necessary to suppose that the thenar pad has been
retained in _africana_ and has been lost in the living _erminea_. The
alternate possibility, namely, that the thenar pad was a relatively
recent acquisition in the _africana_ line seems less probable. The tail
of _erminea_ is of "average" length and in size of entire animal
_erminea_ is intermediate between the other American weasels.
Structurally, _Mustela erminea_ appears to be nearest the stem form
from which all of the living weasels ascended. Its present holarctic
distribution is in harmony with the view that it is a direct descendant
from the stem form because the stem forms of most of the known kinds of
mustelids appear to have lived in the holarctic region. To be sure,
_Mustela erminea_ is regarded as having undergone some progressive
change in structure, but less than the other weasels, in the period of
time when the weasels were evolving from the stem form.

The least weasel, _Mustela rixosa_, seems to be an ancient type and to
judge from the size and proportions of its parts, was differentiated
from the _erminea_ stem at a time earlier than were the other American
Recent species of weasels. In size, in reduction of the tail, and in
proportions of the skull, _M. rixosa_ is, in each instance, the most
aberrant of all the weasels, _Mustela nivalis_ of Europe and western
Asia included. This aberrancy results from the retention of certain
primitive features, in the teeth and basicranial region, and from
specialization in proportions of the skull. The skull is long, deep,
and narrow. These proportions probably are adaptations permitting the
animal to follow the smaller kinds of mice into their burrows. In most
of that part of North America where _erminea_ and _rixosa_ occur
together, _erminea_ is a much larger animal and takes as prey almost
all kinds of land vertebrates that it is powerful enough to kill. These
include varying hares and ptarmigans. The least weasel, _rixosa_, can
hardly manage such large prey and lives on the smaller rodents.
_Mustela rixosa_ may eat numbers of insects (see page 176 beyond),--a
kind of food which _Mustela erminea_ is not known to eat. Apparently
the two species are able to live in the same areas because each eats a
somewhat different kind of food than does the other and hence they do
not compete to the point where one is crowded out by the other. This is
the case in the latitudes where the two species of weasels are of
different bodily size, but in the southernmost latitudes where these
two species occur, _erminea_ becomes almost as small as _rixosa_ and
only one of the species, to the exclusion of the other, occurs in a
given area. All through the Rocky Mountains, south of Montana and in
the territory west of these mountains all the way to the Pacific Coast,
only the small subspecies of _erminea_ is to be found. In the
Alleghenies of the eastern United States only _rixosa_ occurs. In New
England where _erminea_ approaches the size of _rixosa_, the latter is
unknown. Probably this exclusiveness results from competition for food,
although competition for dens, safe breeding places and other
requirements of life may be involved.

The species _erminea_ invaded the western United States and in the
process of invasion probably developed there the small size appropriate
to permit _erminea_ to live in that latitude before it could do the
same thing in the Appalachian region. Later than _erminea_, the least
weasel, _Mustela rixosa_, which was small to begin with, also spread
southward from the holarctic region, stopped short in the western
United States at the northern boundary of the area in which _erminea_
was of small size, but in the Appalachian region of the eastern United
States continued on southward to the limits of temperature tolerant for
it because _erminea_ had not yet penetrated into that region and no
other small carnivore was there to offer competition.

The long-tailed weasel, _Mustela frenata_, occurs mostly south of the
regions inhabited by the ermine, and mostly south of the region
inhabited by the least weasel which appears to live as well with
_frenata_ as with _erminea_. It is true that _erminea_ and _frenata_
occur in the same region, but this is a relatively narrow belt across
the United States; and from within it a person cannot go far either
north or south without reaching a region in which only one of the two
species occurs. Exception has to be made for the Rocky Mountains and
the Sierra Nevada, where _erminea_ is of exceptionally small size. In
these mountains and in the boreal mountainous parts of the intervening
region of the United States, _erminea_ and the large-sized _frenata_
occur together over a wide area. Presumably the two occupy different
ecologic niches, much as _rixosa_ and _frenata_ probably do where they
occur together.

Most of the geographic range of the long-tailed weasel, _M. frenata_,
is in the temperate region. Structurally, this species is the most
advanced of the American weasels. Its dentition is the most highly
specialized for cutting. M1 is relatively small and the inner lobe is
slightly larger than the outer lobe. The skull, throughout, is more
modeled than in the other species; the rostrum, the lower jaws and the
teeth--all parts of the offensive equipment--are well developed
relative to the corresponding structures in other weasels; the
basicranial region exhibits an advanced stage of development in that
the tympanic bullae show the maximum degree of inflation. Also, they
are thrust far out of the braincase, thereby providing more room for
the relatively larger brain which is protected by a more solidly built
braincase than in _erminea_.

Several subspecies of _Mustela frenata_ occur in the tropics, that is
to say, south of the Mexican tableland and on the coastal plain to the
east of it. Each is structurally more primitive than subspecies of the
temperate region. As compared with _Mustela frenata frenata_ of the
temperate Mexican tableland the size in these tropical subspecies is
smaller; the tail is shorter; the braincase and entire skull are less
modeled; the postorbital breadth is more; the teeth are smaller; the
deuterocone of P4 is not so far anterior to the protocone; the tympanic
bullae are less inflated, are farther removed from the foramen ovale,
and a larger proportion of each bulla is contained within the
braincase. These features serve to set off from northern races of
_frenata_ all those subspecies of _frenata_ which occur from southern
México southward to the northern and western limits of the Amazon
drainage of South America. The Amazon Basin is inhabited by another
species, _Mustela africana_, having more primitive characters.

In the species _frenata_, the explanation for this abrupt change in
characters between the animals of the temperate highlands and those of
the tropical lowlands may be this: In the early Pleistocene, after the
emergence of much or all of Central America took place, weasels
distributed themselves over the Isthmus and into South America. These
weasels were more generalized in structure than those now inhabiting
the uplands of México. Failure of this stock of weasels often to cross
some still-persisting water barrier, or failure of this stock to cross
some water barrier that was widened or reformed because of a rise in
sea level in some one of the interglacial periods of the Pleistocene
cut the _frenata_ stock into two or more parts. After the land
connection was established or re-established and when the necessary
precedent plants and rodents again had established themselves, the two
groups of weasels, one from the northern tableland of México, and the
other from the southern area of tropical complexion, met. The weasels
of the _frenata_ stock that reinvaded the area from the north probably
did so by following along the chain of high volcanic cones and narrow
uplifts. If and when a subsequent inundation occurred in some
part of Central America, weasels were stranded on the adjacent
mountains--converted into islands--only the higher parts of which were
above water. _Mustela frenata costaricensis_ and _Mustela frenata
goldmani_ may be examples of a northern stock of weasel that pushed
southward in the highlands and became stranded for a short time.
Following the latest emergence of land to provide a continuous highway
between the two continents, weasels from the south and the insular
populations, as for example, _M. f. costaricensis_, were the first to
invade the low tropical areas most recently under water. When the
Pleistocene history of Central America is better known, the facts will
provide a useful means of testing the hypothesis that has been outlined
immediately above.

As explained above, fossil specimens of _M. frenata_ from deposits of
the last half of Pleistocene time show that no appreciable change
occurred in some areas, for example, in the vicinity of Hawver Cave and
Samwel Cave of California, and that but slight change occurred in other
areas, for example, in southern California (fossils from Rancho La
Brea) and probably in the central United States (fossil from Conard
Fissure). It is possible to imagine, therefore, that the two groups of
weasels, one occurring southward only as far as the highlands of
Central America and the other occurring in northern South America, had
not differentiated sufficiently in the period of their isolation to
prevent crossbreeding when they last came into contact. If the
separation of the two groups had been maintained for a longer period,
the two groups, tropical weasels and austral weasels, probably would
have been so different when the two met as to prevent crossbreeding and
they would have constituted two full species instead of only one.

_Mustela africana_ is the most primitive of the American weasels. Some
of the most important structural features that mark it as such are in
the basicranial region. The tympanic bullae are less inflated than in
other weasels, are pointed anteriorly and posteriorly, and do not have
the lateral margins carried outward to the outer margins of the
braincase. The mastoid sinus is not involved, by inflation or marked
modification in the production of the auditory complex. Between the
alisphenoid and the squamosal there is a clear demarcation posteriorly
from a point directly lateral to the foramen ovale. This demarcation
permits a transverse rounding of the alisphenoid to form a longitudinal
ridge between the anterior margin of each bulla and the base of the
pterygoid of the same side. Nevertheless, there is no such
specialization of this primitive, structural feature such as occurs in
some African and Asiatic mustelids in which the tympano-pterygoid part
of the alisphenoid fuses with the tip of the hamulus of the pterygoid.
However, the tympano-pterygoid eminence has not been obliterated in _M.
africana_ as it has in the other American weasels. Another primitive
feature in the basicranial region of _M. africana_ is the tendency
toward separation of the paroccipital processes from the tympanic
bullae. The thenar pad of the foot probably is an inheritance from a
primitive ancestor since the pad is present in the viverrids and in a
majority of mustelids judged to be more primitive than _Mustela_.

Some specializations are obvious in _Mustela africana_. One is the
reduction in number of premolars; p2 is absent whereas it is normally
present in the other weasels; P2 has one instead of two roots; and, in
relation to the other teeth, m2 is smaller. The shortness of the
preorbital part of the skull in relation to the length of the skull as
a whole may reflect the mentioned reduction of the premolars or
retention of a primitive shape of skull, or both. Also, certain
features which denote immaturity in other weasels are retained in
adults of this species, as for example, sutures on the dorsal face of
the preorbital region of the skull.

[Illustration: FIGS. 17-22. Views of the feet of American weasels
(subgenus _Mustela_) to show differences in number and arrangement of
the pads and variation in degree of hairiness of the soles. × 1-1/2 In
each figure, left-forefoot on left, and left hind foot on right.

FIG. 17. _M. rixosa rixosa_, Halifax, N.S.; juv., [F], 7425 U.S.N.M.

Fig. 18. _M. erminea richardsonii_, Ft. Chimo; ad. [F], 14866 U.S.N.M.

Fig. 19. _M. frenata noveboracensis_, Mich., July 7, 1913; ad. [M],
44689 M.Z.

Fig. 20. _M. f. frenata_, Brownsville, June 1, 1892; yg. [M], 34043
U.S.N.M.

Fig. 21. _M. frenata panamensis_, Panamá, February 17, 1911; sad. [F],
type.

Fig. 22. _M. a. africana_, Pará, Brazil, Sept., 1908; yg. [M], 37475
A.M.N.H.

Figs. 17, 18 and 19. Drawn from specimens preserved in alcohol.

Figs. 20, 21 and 22. Drawn from relaxed feet of dried skins.]

_Mustela africana_, all characters considered, is the most aberrant of
the American weasels. That is to say, greater difference prevails
between _M. africana_ and any other American weasel than exists between
any other two American weasels. The distinctive cranial and dental
characters, excepting the reduction in number of premolars, are of a
primitive nature. For example, the relatively wide postorbital region,
the large braincase that is inflated anteriorly, and the flattened
tympanic bullae are points of resemblance to the holarctic _Mustela
erminea_, the species which is regarded as most closely resembling the
stem form. Also, the mentioned characters in adults of _M. africana_
resemble ontogenic stages passed through by other weasels.
Consequently, it is thought that _M. africana_ crossed the
filter-barrier from North America to South America, remained isolated
from the original stock for a length of time sufficient to permit
_africana_ to differentiate from North American weasels and _vice
versa_ to such a degree that crossbreeding with the _frenata_ stock was
prevented when _frenata_, at a later time, pushed southward over the,
then zoölogically less-effective, water barrier, or continental bridge
if it was by this time in existence.

[Illustration: FIG. 23. Diagram indicating probable relationships of
the species of American weasels.]

The four full species of American weasels may well be thought of as
having the same stem form of which _erminea_ is the most nearly direct
descendant. Geographic and climatic changes may have operated to
isolate, and then to foster morphologic differentiation of, first
_rixosa_ in Eurasia, next _africana_, third the _tropicalis_ section of
_M. frenata_, and finally _M. frenata_ itself, leaving _M. erminea_ as
a modern version, somewhat altered to be sure, of the stem form. Some
of these ideas are expressed in figure 16. The climate is different in
the ranges of the several species and the climate has changed through
time in the ranges of at least many subspecies. Natural selection of
morphological features best adapted to a particular kind of climate
probably has altered some species more than others. _M. erminea_ in
almost every one of its characteristics is generalized and potentially
progressive whereas _africana_ retains more characters which are truly
primitive along with a few which are specializations. _M. africana_ is
potentially the least progressive of any of the American weasels. The
most specialized weasels are the North American races of _Mustela
frenata_. A progressive series of increasing specialization is
comprised in (1) _M. africana_, (2) the _M. tropicalis_ (Central
American, lowland) section of _M. frenata_, and (3) the races of _M.
frenata_ in North America.

Considering now features of the environment which have obviously
influenced the distribution and speciation of weasels, water barriers
are important. Bering Strait, Carquinez Strait (along with San
Francisco Bay) which opens through the Golden Gate, and the channels
between the islands of southeastern Alaska, have contributed to the
formation of subspecies. The difference is really slight on the two
sides of Bering Strait and San Francisco Bay and is slightly more on
two sides of each of several of the channels between the islands of
southeastern Alaska. The differences between the weasels on the two
sides of one of these water barriers supposedly result from the
preservation in animals on one side, or on one island, of small
mutations, which would be swamped by crossbreeding if the water barrier
were not present. The effect of this isolation is easily seen if
ermines from the Queen Charlotte Islands are compared with those of the
opposite mainland. The degree of morphological difference is great.
Isolationwise, the Queen Charlotte Islands are the seaward end of a
chain, beginning with Admiralty Island in southeastern Alaska, and are
farther from the mainland, zoölogically, than the distance in actual
miles across the water channel would suggest. Between any two islands
that are geographically consecutive, however, and between the mainland
and the first island of the chain, the difference in the ermines is
small. In other places, water barriers of equal or greater width have
contributed little if anything to the differentiation from one another
of weasels on the two sides of the water barrier. The strait between
eastern Canada and Newfoundland is an example.

The absence of water, or scarcity of it to a degree that closely
approaches absence, in any large area appears to prevent weasels from
living there. At any rate, the one sizeable region of North America
from which weasels are unknown is the desert of the southwestern United
States and adjoining part of northwestern México. More precisely, in
western Arizona, the Mohave Desert and the desert of northwestern
Sonora, collectors of mammals have repeatedly sought small carnivores
without ever finding any weasels.

Degree of moisture is closely correlated with color in weasels.
Humidity and cloudiness as well as actual precipitation seem to be
involved. Even if we take into account average annual rainfall alone,
the darkest-colored weasels are found in the areas of heaviest rainfall
and the lightest-colored weasels in areas of lightest rainfall (extreme
type of desert where no weasels occur being excepted). In any large
region where there is a geographic gradient in rainfall, the transition
from light to dark color almost exactly parallels the increase in
amount of rainfall. Within a given species the same color reappears in
widely separated areas that have the same amount and seasonal
distribution of rainfall. This correlation is repeated so often that
one can almost certainly say that heavy rainfall, or the associated
phenomena of high humidity and cloudiness, acting separately or
together, causes an increase in intensity of color. Relative extent of
the color of the upper parts and underparts and presence and absence of
light facial markings seem also to be correlated, in a more general
way, with differences in rainfall. A fuller discussion of the nature
and amount of the variation in color is given on page 51.

Temperature seems not to be an important factor in directly limiting
the distribution of weasels, since _M. frenata_ occurs from the hottest
to some of the coldest parts of the Americas. Do _M. erminea_ and _M.
rixosa_ range no farther south, than they do at present, because high
temperatures constitute a barrier? No evidence is known to me which
provides an answer, one way or the other, to this question. Granting
that temperature is unimportant in limiting the distribution of
weasels, it seems to cause geographic variation. Increase in mean
annual temperature is correlated with decreased size in _M. erminea_
and with increased size in _M. rixosa_. Temperature, it seems, causes
the hair to vary; the pelage is harsher and sparser in weasels from
tropical regions than in those from boreal regions. Difference in
number of hairs is especially well shown on the soles of the feet. In
the weasels from the far north, the pads are concealed by hair and in
the weasels from the tropical regions the soles are mostly bare. Also,
the hair on the soles of the feet is longer in northern than in
southern weasels. Furthermore there is seasonal change in length of the
hair on the soles of the feet; at a given locality in southern Canada
the hair of the white winter coat is so long on the soles of the feet
as to obscure completely the palmar and plantar pads whereas the hair
of the brown summer coat is shorter and leaves these pads boldly
exposed to view. This seasonal change, as would be expected, is most
marked in animals of northern regions and is not perceptible in those
from the tropics; it is correlated with increase in seasonal change as
the distance from the equator increases.

Temperature and moisture acting together may cause extensive white
facial markings, that neither alone would cause. In _Mustela frenata_
these markings occur where there is heavy rainfall and high mean annual
temperature. Where there is heavy rainfall and a low mean annual
temperature they do not occur and where there is high mean annual
temperature and light rainfall the markings are not pure white but are
of the same color as the underparts. Plate I and the description of
color on page 51 may be consulted in this connection. Extremely high
mean annual temperature together with extremely heavy rainfall may
inhibit the development of light facial markings. _M. f. meridana_,
_panamensis_ and _costaricensis_ are cases in point. In either
direction, north or south, from the territory inhabited by these three
subspecies a similar combination of temperature and rainfall is found
and similar light facial markings appear there.

Considering the delicate response of structure to climate, a person
naturally questions whether or not natural selection accounts for all
of the differences between subspecies. To show that natural selection
determines the color of _Mustela frenata_, it would be necessary to
assume that climate, color, and utility of color are positively
correlated. Although climate (rainfall) and color are correlated in
such a manner that three subspecies of weasel in places as far apart as
New England, Perú, and the state of Washington are colored alike, other
features of the three environments are unlike. Kinds of animals which
the weasel catches for food, and flora in which the weasel finds
concealment, are dissimiliar. If natural selection alone determined the
color, some difference in color would be expected between the weasel
which needed to be obliteratively colored, that is camouflaged, the
better to catch a _Phyllotis_ in Perú and the weasel in Washington
which needed nature's aid in catching _Microtus_. _Mustela frenata
goldmani_ of the highlands of southern México, which is known to attack
the huge pocket gophers, _Orthogeomys_ and _Cratogeomys_, has a weaker
dental armature than _Mustela frenata texensis_ which does not have to
overcome prey so formidable as does _goldmani_. Equally formidable
enemies endanger _M. f. goldmani_ and _texensis_. Examples of this
nature could be multiplied. Without actually proving anything
concerning selection, these examples give reason for us to suppose that
some characters are not determined by natural selection.

Another question upon which data obtained from a study of _Mustela_ has
some bearing, is this: Where the geographic ranges of two subspecies
meet, why does not the swamping effect of crossbreeding cause one
subspecies to disappear? Although swamping may have occurred in some
instances, it does not occur in the majority of instances. Witness the
long-continued existence of the living subspecies _Mustela frenata
nevadensis_ of which skulls are available from Pleistocene deposits.
Therefore, its distinctive characters, cranially at least, have been
maintained for a long time. Furthermore, these characters are
maintained over a large geographic region more than a thousand miles
across. On the eastern margin of its range, at the eastern base of the
Rocky Mountains in Colorado, _M. f. nevadensis_ intergrades in a
relatively narrow belt with the lighter-colored, longer-tailed and
cranially different _Mustela frenata longicauda_, which has a
geographic range almost equally extensive. _M. f. longicauda_ also is
uniform in its characters over a large area but at approximately 400
miles east of the base of the Rocky Mountains, it begins to intergrade
with the darker-colored, shorter-tailed and cranially different
_Mustela frenata primulina_ and does so over a belt of 100 miles or
more in width. At any given locality within this wide belt of
intergradation the range of individual variation ordinarily does not
exceed that in animals from a given locality well within the geographic
range of _M. f. longicauda_. In the narrow belt of intergradation along
the eastern base of the Rocky Mountains, the range of individual
variation at several places is greater than in animals from a given
locality well within the geographic range of _M. f. longicauda_ or for
that matter from well within the geographic range of _M. f.
nevadensis_.

Considering the dominance and recessiveness of genes and the genetic
mechanism in general by which characteristics of offspring are
inherited from their parents, it would seem that _M. f. longicauda_ and
for that matter _M. f. nevadensis_ and _M. f. primulina_ would lose
their distinctive characteristics because of the crossbreeding that is
every year going on between _longicauda_ and _nevadensis_ on the one
hand and between _longicauda_ and _primulina_ on the other hand.

Sumner (1932:84) suggests that homogeneity is prevented by population
pressure. Applying his suggestion to the species _Mustela frenata_ we
could say that the subspecies _longicauda_ pressing westward meets
strong pressure from the subspecies _nevadensis_ pressing eastward and
that the width of the zone of intergradation between the two subspecies
varies inversely with the strength of the population pressure from the
two sides. Sumner recognizes that according to his hypothesis the two
contiguous races would remain distinct only so long as there was a
preponderance of centrifugal movement from both of the centers of
dispersal. Sumner (_op. cit._:85) recognizes that an abrupt change of
environmental conditions could account in part for the boundaries of
the ranges of the two subspecies and finally that his hypothesis does
not certainly answer the question of why crossbreeding does not result
in homogeneity between two subspecies with contiguous geographic
ranges.

The hypothesis of harmoniously stabilized complexes of genes was
offered by Timofeeff-Ressovsky (1940:124) to explain why the swamping
effect of crossbreeding does not obliterate subspecies. The hypothesis
takes into account that any one of several characters of a subspecies
may be caused by several genes. Some characters of this kind may be
favored by natural selection more than others. In the belt of
intergradation between two subspecies, where two of these favored
characters meet, a "biological tension" as Huxley (1939:415) terms it
"will result, which will produce _partial discontinuity_ between the
two groups. Each group will evolve a gene-complex which is not only
broadly adapted to the external environment of the central area of its
range, but is also harmoniously stabilized, in adaptation to the
internal genetic environment, by the selection of modifiers." Crosses,
that is to say intergrades, between the two subspecies will lack this
stabilization and will therefore be at a selective disadvantage. The
zone of intergradation will therefore remain narrow; intermediates are
constantly being brought into existence there by crossing but are as
constantly being extinguished by selection.

These two hypotheses are the best that geneticists yet have offered.
Neither has been tested and both, as originally proposed, would hardly
apply everywhere because there are some contradictions.

I can offer no better explanation--in fact no original one as good--but
would emphasize that under similar climate, weasels remain constant in
character, or at most do not vary beyond certain limits. Crossing at
the margins of ranges of two subspecies does not result in homogeneity
of weasels. There is, therefore, some stabilizing influence, or
influences, that maintain, and even develop, structural characteristics
of weasels in opposition to the contrary tendency of crossing.

That this influence not only maintains uniform characters over areas of
large extent, but also permitted their development over large
geographic areas, must logically be supposed, for otherwise,
considering the swamping effect of crossing, such variations would not
have made their appearance in more than a few individuals. Also, if the
races had been formed in response to some kind of physiological
differentiation, or other non-climatic cause, the characters of the
population in the belt of intergradation probably would disappear in a
short time. In any event the close correlation between degree of change
in weasels and degree of change in climate, at once makes one suspect
that climate has been the deciding factor. Finally, when one recalls
that in certain parts of the animal, certain characters invariably
appear under similar climates and never under dissimilar climates, the
evidence is almost conclusive that, given long enough time, the animals
vary in response to climate. The variations (characters) may be induced
indirectly, but are no less exactly reproduced than if they can be
shown to be induced directly.

In considering how the species and subspecies of American weasels were
formed and in attempting to account for some of the individual
characters, it is profitable to view the facts in the light of some of
the theories of species-formation--theories that are accessory to that
of organic descent and that are concerned with the _modus operandi_ of
organic descent.

In any group of closely related species some of them, by the laws of
chance, are almost certain to be more primitive than others. _Mustela_
is no exception and the more primitive species closely match, in
several characters, ontogenetic stages passed through by more advanced
species. Jaeckel's (1902) theory of metakinesis, therefore, is to be
considered since it postulates that many cases of epistasis occur; that
is to say, that many sexually adult animals are arrested in
development in early otogenetic stages and undergo no further
development. Although this theory is appealing upon initial
consideration, it is less so when we recall that in _Mustela_ there is
a direct correlation of increasingly primitive structure with
decreasing latitude as one proceeds from the steppe of North America
southward to the equator. It follows that the conditions seen in
_Mustela_ can be explained even better than by metakinesis, by assuming
that the several species have differentiated from a stem form at
different times, have developed at different rates, have developed in
different directions and that ontogeny recapitulates phylogeny.

The theory of Age and Area (see Willis, 1922) holds that the species of
widest distribution are, on the average, the oldest, and that the
species which are distributed over small areas are, in general, of
recent origin. So far as the weasels are concerned, little support is
given to this theory. The same can be said of any one of the teological
theories, including the orthogenesis of post-Darwinian writers. All of
these imply a determinate line of variation controlled by the inherent
qualities of the organism. The idea that the several species of
_Mustela_ result from mutations of large degree and sudden appearance
is contrary to the evidence accumulated. In fact the evidence rather
clearly indicates that the mutations which may have occurred were of
small degree and in most instances owe their preservation to natural
selection.

The data obtained by the study of weasels accords almost exactly with
the theory of species-forming embodied in Matthew's (1915) "Climate and
Evolution." Although the essential features of this theory were made
out from a study of families and orders and therefore would not be
expected to apply to members of only a genus or subgenus, the facts
known about the present distribution of American _Mustela_,
nevertheless, are strikingly in accord with the ideas advanced by
Matthew. In the first place, climate is an important factor in the
evolution of the weasels. In the second place, the line of migration
seems to have been outward from the holarctic region. In the third
place, the geographic changes necessary to explain the present
distribution of the species of _Mustela_ are not extensive and do not
affect the permanency of oceans as defined by the continental shelf.
These three statements are, almost verbatim, those made in the first
three of the five points of Matthew's (1915:172-173) thesis. The
remaining two points of Matthew's thesis have to do with
generalizations based on evidence obtained from sources outside the
scope of the present study.

Furthermore, the relative degrees of specialization of the different
species and subspecies in relation to their geographic distribution are
in accord with the ideas elaborated by Matthew. For instance, the most
primitive species is farthest south from the probable center of
dispersal, the holarctic region. Also the full species become
progressively more primitive as one proceeds southward from the
holarctic, or at least from the northern half of the nearctic, region.
Although, in view of the known geological changes that have occurred in
the Caribbean region, we cannot say that the more primitive species owe
their positions entirely to having been pushed farther south from the
center of dispersal by actual and _continuous_ contact and competition
with the more advanced species, this seems to have been the case in a
general way. At any rate the more primitive kinds seem to have been
prevented from pushing northward by the more advanced kinds which
developed there and the latter have actually pushed southward.

Additionally and in review: There is strong indication that the
American species of weasels were formed by gradual and slow change.
Much of this change probably is the result of natural selection
operating on fortuitous variations of a minor nature, but, also,
particular features of the environment, especially climate, and more
especially amount of rainfall, seem to compel variations that
differentiate subspecies and that characterize full species--compel
some of them without the direct operation of natural selection, or at
least compel them within limits so wide that natural selection exerts
no exact control.



HISTORY OF CLASSIFICATION


In the earlier accounts of American weasels, from the time of Linnaeus
and before, up until 1890, names then in use for European weasels
frequently were applied also to those in North America. For the next 50
years, and almost without exception after 1896, the American weasels
were regarded as specifically distinct from those in the Old World. In
this 50-year period many new names were proposed, usually as full
species, although now that material from more localities has been
brought together and studied, geographic intergradation is evident
between many of the named kinds and most of these names now therefore
take only subspecific rank. In 1933 Glover M. Allen showed that
_Mustela rixosa_ occurred also in the Old World, and in 1943 I
emphasized that a second American species, _Mustela erminea_, was
circumpolar in distribution. In neither _rixosa_, nor _erminea_,
however, were the subspecies the same in the two continents. To this
general outline of the nomenclature, exception must be made for weasels
of the southwestern United States, México and Central America, and
South America, because as early as 1813 a distinctive name was given to
one of these and weasels from the three areas mentioned were, so far as
I know, never given names of Old World kinds.

The first paper that could be regarded as revisionary in nature was
"Remarks on the species of the genus Mustela" by the zoölogist and
world-traveler, Charles L. Bonaparte, in Charlesworth's Magazine of
Natural History, for 1838. In that paper three new names, _Mustela
cicognanii_, _M. richardsonii_ and _M. longicauda_, all still valid,
were proposed for American weasels.

Audubon and Bachman in their "Quadrupeds of North America," which
appeared in parts from 1845 to 1853, recognized 5 species. Actually
they were dealing with only 3 taxonomically valid kinds. For one of
these, _Mustela frenata noveboracensis_, they were misled by the
difference in size between males and females, and in the males by the
presence of a brown coat in some and a white coat in others. The male
that was white in winter they regarded as _Putorius ermineus_ of the
Old World; the male that was brown in winter they designated by their
earlier proposed name _P. fuscus_, and the female they named _P.
agilis_. The ermine, subspecies _M. erminea cicognanii_, they called
_P. pusillus_. Their fifth name, _P. frenatus_, included at least some
animals that today are assigned to the subspecies _M. frenata frenata_.
Each of three and perhaps four of the five names employed by Audubon
and Bachman embraced individuals of more than one species and in that
sense the names were composite.

Only five years later, in 1858, Professor Spencer Fullerton Baird's
great work, "The Mammals of North America," made it clear that no
American weasel was identical (in the modern subspecific sense) with
any Old World weasel, and he applied most of his names in a correct
zoölogical sense. It is true that he thought that the female weasel of
the eastern United States was specifically different from the male,
misapplied to it the name _richardsonii_, and did not correctly
allocate every one of the few poor specimens available to him of the
little ermine (_M. e. streatori_) of the Pacific Coast; but he did
recognize that the least weasel was a distinct kind and his treatment
in general was excellent.

After Baird came a period of great confusion in which most writers did
no better than had Audubon and Bachman, ordinarily confusing the two
sexes as different species, and, in 1877 in his "Fur-bearing Animals,"
Elliot Coues went rather to the other extreme and allowed only 4 kinds
to all of the Americas, regarding two of these, for purposes of
zoölogical nomenclature, as identical with the European species.

But, in 1896 Outram Bangs published "A Review of the Weasels of Eastern
North America" in which he correctly recognized eight kinds. Although
some of these were treated by him as full species, whereas the material
accumulated since 1896 has shown that subspecific status is in order,
his names, still in use, were correctly applied in every instance, save
probably one. This was his use of _Putorius richardsonii_ for the
animal now known as _M. e. arctica_. Unlike the earlier, excellent
treatment by Baird, this accurate one by Bangs was heeded and followed
by subsequent writers. For example, Dr. C. Hart Merriam in the same
year, 1896, accepted Bangs' conclusions except for correcting the
application of the name _richardsonii_. The principal contributions of
Merriam's paper "Synopsis of the Weasels of North America" were first,
the wider geographic scope and second, the naming as new of several
kinds outside the geographic area studied by Bangs. Otherwise the work
was not up to Dr. Merriam's usual standard and the internal evidence of
haste in its preparation and the superficial study of some of the
material at his disposal explain why the weasels of North America since
that time have been but little better understood than in 1896. Baird
and Bangs, then, unquestionably did the best systematic work on the
American weasels.

In 1916 Dr. Joseph A. Allen published a valuable paper on the South
American weasels. The material available to him was inadequate and
prevented a thoroughly satisfactory treatment. There are too few
specimens even today to permit of a thorough treatment of the South
American weasels in the present paper; nevertheless the material today
is more nearly adequate than it was in 1916 and it is hoped that the
systematic arrangement is correspondingly improved.


Chronological List (annotated) of Specific and Subspecific Names
Applied to American Weasels

At least eighty-seven specific and subspecific names have been proposed
for American weasels. Of these sixty-nine are now regarded as valid
designations of recognizable subspecies. The average is 1.2 names per
subspecies. Some names in the following chronological list were a
second time applied wholly or in part to some other kind of weasel. In
general, mention of the second or any other later application is
omitted from the following list but two usages of _agilis_ (1844 and
1853) and of _americana_ (1865) are recorded.

     1734. =javonica= (_Mustela_) Seba, Locupletissimi Rerum naturalium
     Thesauri ..., 1:77, 78, pl. 48, fig. 4. The weasel to which this
     name was applied was said to have come from Java. Since no animal
     answering to the description has again been found in Java, and
     because specimens from Central America or possibly some from
     northern India, may do so, it is conceivable that Seba was the
     first to distinguish by name an American weasel from those in the
     Old World. My attempts to locate the specimen concerned in places
     where it might have been preserved along with some of the other
     specimens thought to have belonged to Seba have been fruitless.
     Since it is impossible positively to link Seba's description with
     any known weasel, no further use is made of the name _javonica_ in
     the present account.

     1772. =erminea= (_Mustela_) Forster [= _Mustela erminea
     richardsonii_], Philos. Trans., London, 1772:373. Forster's use of
     the name is one of the earliest applications of it to American
     animals. The name dates from Linnaeus, Syst. Naturae, (10th ed.)
     1:46, 1758, with type locality in Europe. In the subspecific sense
     the name applies to the ermine which occurs over most of the
     Scandinavian Peninsula, if Miller (1912:387) be followed in
     regarding the type locality as Upsala, Sweden. If, instead,
     Cabrera (1913A:394-396) be followed in regarding the type locality
     as in Switzerland, the name, in the subspecific sense, will apply
     to the ermine of continental Europe. As the earliest available
     name applied to the circumpolar species concerned, it is used now
     as the name of the species in the New World as well as in the Old
     World. From the time of Forster until approximately 1890 the name
     _erminea_ by many, but not by all, authors was applied to the
     American weasels in the belief that they were zoölogically
     indistinguishable from those in the Old World. From 1896 to 1943
     the name was not used by American authors at all because the
     ermine of America was in 1896 treated nomenclaturally by Merriam
     as specifically distinct from the animal in the Old World. Since
     1943 _erminea_ has been used in the specific sense for American
     animals in recognition of the circumpolar distribution of the
     species. Some of the early allocations of American specimens to
     _erminea_ probably resulted in a composite use of the name in that
     one or another subspecies of the American species _Mustela
     frenata_ may also have been included with individuals truly of the
     species _erminea_.

     1772. =nivalis= (_Mustela_), Forster, Philos. Trans., London,
     1772:373. This is one of the early applications of this name to
     American weasels of small size, made in the belief that they were
     taxonomically the same in America and Europe. Linnaeus, Syst. Nat.
     (12th ed.) 1:69, 1766 is the authority for the name [_Mustela_]
     _nivalis_, and the Province of Vesterbotten, Sweden, is regarded
     as the type locality. The name is in use today for the common
     weasel of Europe and parts of Asia. Animals of the species
     _nivalis_ are intermediate in size between _Mustela erminea_ and
     _Mustela rixosa_. The name as used for American animals by some
     authors who wrote later than Forster did, probably was composite
     in that these authors may have applied the name to the small
     weasels of North America and thus may have intended it to apply
     not only to _Mustela erminea cicognanii_ but also to females of
     _Mustela frenata noveboracensis_, and conceivably to both sexes of
     _Mustela rixosa_ of any American subspecies.

     1813. =Brasiliensis= (_Mustela_) Sevastianoff, Mem. Acad. Imp.
     Sci. St. Petersburg, 4:356-363, table (= plate) 4. This name was
     proposed for a weasel brought to St. Petersburg by Capt.
     Krusenstern on his return from a voyage around the world. The
     animal was said to have come from Brazil, but to judge from the
     description, came instead from México, Central America, or west of
     the Andes in South America, and was based on some one of the
     subspecies of _Mustela frenata_. Although the name was in use for
     more than 60 years it was shown by Merriam (1896:27) to be
     unavailable because it was preoccupied by _Mustela brasiliensis_,
     a name earlier used by Gmelin (Syst. Nat., ed. 13, p. 93, 1788)
     for a South American otter.

     1815. =vulgaris= (_Mustela_), Ord, Guthrie's Geography as
     reprinted by Rhoads in 1894, vol. 2, p. 291. This use by Ord is
     one of the earliest applications of this name to American weasels,
     in the belief that the smaller weasels of North America and Europe
     were zoölogically the same; [_Mustela_] _vulgaris_ seems
     originally to have been proposed in 1777 by Erxleben on p. 471 of
     vol. 1 of his Syst. Regni Anim., for the weasel of the temperate
     part of Europe and to be a synonym of _Mustela nivalis_ Linnaeus
     (1766). Probably the name as used by Ord was composite in the
     sense that he may have intended it to apply to females of _Mustela
     frenata noveboracensis_ as well as to one or both sexes of
     _Mustela erminea cicognanii_ and, if he ever saw them, to the two
     sexes of _Mustela rixosa_ (one or several subspecies).

     1818. =africana= (_Mustela_) Desmarest [= _Mustela africana
     africana_], Nouv. Diction, d. Hist. Nat., 19:376. In 1808 E.
     Geoffroy St.-Hilaire visited Portugal and was given several
     African primates and the specimen of _Mustela_ named by Desmarest
     in 1818 who wrongly supposed that it, like most of the primates,
     came originally from Africa. After the name had been misapplied
     for 95 years Angel Cabrera showed that it pertained instead to the
     tropical weasel of Brazil. Of distinctive names applied to
     American weasels today, this is the one first proposed.

     1832. =frenata= (_Mustela_) Lichtenstein [= _Mustela frenata
     frenata_], Darstellung neuer oder wenig bekannter Säugethiere, pl.
     42 and corresponding text unpaged. This name is the first one
     available for the long-tailed weasel and therefore applies to the
     species as a whole.

     1838. =Cicognanii= (_Mustela_) Bonaparte [= _Mustela erminea
     cicognanii_], Charlesworth's Mag. Nat. Hist., 2:38. The name
     erroneously spelled _Cigognanii_ was correctly spelled on page 39.
     For a detailed consideration of this name see the account of the
     subspecies _cicognanii_ on page 120.

     1838. =Richardsonii= (_Mustela_) Bonaparte [= _Mustela erminea
     richardsonii_], Charlesworth's Mag. Nat. Hist., 2:39. Until 1896
     the name sometimes was applied to the subspecies now known as _M.
     e. arctica_ and sometimes to part of the subspecies now designated
     as _M. e. cicognanii_ under the principal treatment of which see
     (page 120) for a detailed account of the basis of the name
     _=richardsonii=_, and the reasons for regarding Fort Franklin as
     the type locality.

     1838. =longicauda= (_Mustela_) Bonaparte [= _=Mustela frenata
     longicauda=_], Charlesworth's Mag. Nat. Hist., 2:39. The type
     locality appears to be Carlton House, Saskatchewan, and the name
     always seems to have been applied to the long-tailed weasel of the
     Great Plains, although in some earlier accounts the name was used
     in a more inclusive sense to refer also to animals now of
     subspecies closely allied to _longicauda_. As with the two
     preceding names, a detailed consideration of the basis for, and
     application of, this name is given on pages 120-123 in the account
     of _Mustela erminea cicognanii_.

     1840. =Noveboracensis= (_Putorius_) Emmons [= _Mustela frenata
     noveboracensis_], Quadrupeds of Mass., p. 45. This name was
     credited by Emmons to De Kay who in the same year published it in
     his report on the "Zoology of New York" but without a description
     and De Kay's name is a _nomen nudum_. Emmons' was the first use of
     the name accompanied by a recognizable description and therefore
     the name must date from Emmons although this obviously was not his
     intent since he credited the name to De Kay.

     1842. =fuscus= (_Putorius_) Audubon and Bachman [= _Mustela
     frenata noveboracensis_], Jour. Acad. Nat. Sci., Philadelphia, 8:
     (pt. 2) 288.

     1842. =pusilla= (_Mustela_) De Kay [= _Mustela erminea
     cicognanii_], Nat. Hist. of New York, Zool., Pt. 1, Mammalia, p.
     34. This name was proposed for small weasels of 12 to 13 inches in
     length of which the tail amounted to a fourth of the same and
     although obviously applying in considerable part to the earlier
     named _M. e. cicognanii_ seems to have included some individuals
     of the also earlier named _M. f. noveboracensis_.

     1843. =xanthogenys= (_Mustela_) Gray [= _Mustela frenata
     xanthogenys_], Ann. and Mag. Nat. Hist., 11:118, February, 1843,
     was applied to all of the long-tailed weasels of California that
     had light-colored facial markings. Merriam in 1896 suggested that
     San Diego was the type locality and in 1899 Bangs proposed the
     name _mundus_ for the California weasel north of San Francisco Bay
     thus restricting the application of the name _xanthogenys_. In
     1936 Hall further restricted the application of the name and
     applied it to the long-tailed weasel of the big interior valley of
     California, pointing out that the name was correctly applied to
     this weasel of the big interior valley or possibly instead to the
     race named _munda_.

     1844. =agilis= (_Mustela_) Tschudi [= _Mustela frenata agilis_],
     Untersuch. ü. die Fauna Peruana, p. 110, is a name applied today
     to the race of weasel of the Temperate Zone of the western Andes
     and intermountain valleys of Perú.

     1851. =nigripes= (_Putorius_) Audubon and Bachman [= _Mustela
     nigripes_], Quadr. N. Amer., 2:297, 1851, applies to the
     black-footed ferret of North America.

     1853. =agilis= (_Putorius_) Audubon and Bachman [= _Mustela
     frenata noveboracensis_], Viv. Quadrupeds N. Amer., 3:184, pl.
     140. This name was proposed for the female in the mistaken belief
     that it was specifically distinct from the larger male for which
     several names already were available. Also Tschudi in 1844 had
     already used the name _Mustela agilis_ for a South American
     weasel.

     1864. =aureoventris= (_Mustela_) Gray [= _Mustela frenata
     aureoventris_], Proc. Zoöl. Soc. London, 1864:55, pl. 8, February
     9, 1864, is the name applicable to the dark-colored weasel of the
     Pacific coastal region of Ecuador and Columbia.

     1865. =americana= (_Mustela erminea_ Var. 3) Gray, Proc. Zoöl.
     Soc. London, 1865:111. The larger individuals of American weasels
     of both _Mustela erminea_ and _Mustela frenata_ from the Atlantic
     Coast to as far west as Carlton House, Saskatchewan, were lumped
     under this name because Gray desired more information than he then
     had before recognizing as different from one another several
     species proposed for America up to the time concerned. The name is
     unavailable because it is preoccupied by _Mustela americana_
     Turton (1806) the name for the American marten.

     1865. =americana= (_Mustela vulgaris_ Var.) Gray, Proc. Zoöl. Soc.
     London, 1865:113. Under this name the smaller weasels of the
     northern and northeastern part of North America were lumped by
     Gray but the name is preoccupied and can be ignored.

     1874. =affinis= (_Mustela_) Gray [= _Mustela frenata affinis_],
     Ann. and Mag. Nat. Hist., 14 (ser. 4):375, 1874, from New Granada
     [= Colombia], had the type locality restricted to Bogotá,
     Colombia, by Allen in 1916, and is applied to the long-tailed
     weasel of the tropical and temperate zones of the eastern Andes of
     Colombia.

     1874. =macrura= (_Mustela_) Taczanowski [= _Mustela frenata
     macrura_], Proc. Zoöl. Soc. London, for 1874, p. 311, pl. 48, May
     19, 1874, applies to the long-tailed weasel of central Perú and
     northern Ecuador.

     1877. =culbertsoni= (_Putorius_) Coues [= _Mustela frenata
     longicauda_], Fur-bearing animals ..., p. 136, 1877, is based on
     specimens from Fort Laramie, Wyoming. In the past the name has
     been regarded as a _nomen nudum_ but there is some reason for
     regarding it as having nomenclatural status. In either event it is
     here arranged as pertaining to the long-tailed weasel of the Great
     Plains which takes the prior name _longicauda_. See the account of
     _longicauda_ for a more detailed account of the name
     _culbertsoni_.

     1877. =aequatorialis= (_Putorius_ (_Gale_) _brasiliensis_) Coues
     [= _Mustela frenata aureoventris_], Fur-bearing animals ..., p.
     142. Proposed "merely as a substitute for Gray's [supposedly]
     preoccupied name," _aureoventris_.

     1881. =stolzmanni= (_Mustela_) Taczanowski [= _Mustela africana
     stolzmanni_], Proc. Zoöl. Soc. London, for 1881, p. 835, November
     15, 1881, is applied to the tropical weasel of the Upper Amazon
     Basin.

     1881. =jelskii= (_Mustela_) Taczanowski [= _Mustela frenata
     macrura_], Proc. Zoöl. Soc. London, for 1881, p. 647, May 17,
     1881, was proposed for the female in the mistaken opinion that it
     was specifically distinct from the larger male which the same
     author previously had named _macrura_.

     1891. =arizonensis= (_Putorius_) Mearns [= _Mustela frenata
     arizonensis_], Bull. Amer. Mus. Nat. Hist., 3:234, June 5, 1891,
     until 1936 was applied to long-tailed weasels of most of the
     western United States west of the Great Plains but by restriction
     since 1936 has been applied only to the animals in parts of
     Arizona and New Mexico.

     1894. =peninsulae= (_Putorius_) Rhoads [= _Mustela frenata
     peninsulae_], Proc. Acad. Nat. Sci. Philadelphia, 1894:152, June
     19, 1894, applies to the weasel of central and southern Florida.

     1896. =alascensis= (_Putorius richardsonii_) Merriam [= _Mustela
     erminea alascensis_], N. Amer. Fauna, 11:12, June 30, 1896, with
     type locality at Juneau, Alaska, has been used for the ermine of
     southeastern Alaska ever since it was proposed. In 1944 separate
     subspecific rank was accorded ermines on several of the islands of
     southeastern Alaska which proportionately restricted the range
     assigned to _alascensis_.

     1896. =streatori= (_Putorius_) Merriam [= _Mustela erminea
     streatori_], N. Amer. Fauna, 11:13, June 30, 1896, applies to the
     ermine of the Pacific Coast from Puget Sound, Washington, south
     nearly to the Golden Gate of California.

     1896. =arcticus= (_Putorius_) Merriam [= _Mustela erminea
     arctica_], N. Amer. Fauna, 11:15, June 30, 1896. Ever since it was
     proposed, this name has been applied to the subspecies of ermine
     of Alaska and the northern parts of Canada.

     1896. =kadiacensis= ([_Putorius arcticus_]) Merriam [= _Mustela
     erminea kadiacensis_], N. Amer. Fauna, 11:16, June 30, 1896, is a
     valid name applied to the ermine of Kodiak Island, Alaska.

     1896. =washingtoni= (_Putorius_) Merriam [= _Mustela frenata
     washingtoni_], N. Amer. Fauna 11:18, June 30, 1896, applies to the
     long-tailed weasel of the southern Cascades of Washington and the
     northern Cascades of Oregon.

     1896. =saturatus= (_Putorius_) Merriam [= _Mustela frenata
     saturata_], N. Amer. Fauna, 11:21, June 30, 1896, was little used
     until 1936 but applies to long-tailed weasel of limited region in
     northern California and southern Oregon.

     1896. =alleni= (_Putorius_) Merriam [= _Mustela frenata alleni_],
     N. Amer. Fauna, 11:24, June 30, 1896, applies to weasel of Black
     Hills region.

     1896. =oregonensis= (_Putorius xanthogenys_) Merriam [= _Mustela
     frenata oregonensis_], N. Amer. Fauna, 11:25, June 30, 1896,
     applies to long-tailed weasel of parts of western Oregon and
     northern California.

     1896. =goldmani= (_Putorius frenatus_) Merriam [= _Mustela frenata
     goldmani_], N. Amer. Fauna, 11:28, June 30, 1896, applies to the
     long-tailed weasel of Chiapas, and parts of Guatemala and
     Salvador.

     1896. =leucoparia= (_Putorius frenatus_) Merriam [= _Mustela
     frenata leucoparia_], N. Amer. Fauna, 11:29, June 30, 1896,
     applies to the long-tailed weasel of Michoacán and Nayarit.

     1896. =tropicalis= (_Putorius_) Merriam [= _Mustela frenata
     tropicalis_], N. Amer. Fauna, 11:30, June 30, 1896, applies to the
     long-tailed weasel of the Tropical Life-zone of Veracruz.

     1896. =spadix= (_Putorius longicaudus_) Bangs [= _Mustela frenata
     spadix_], Proc. Biol. Soc. Washington, 10:8, February 25, 1896,
     applies to the long-tailed weasel of Minnesota and adjoining
     areas.

     1896. =rixosus= (_Putorius_) Bangs [= _Mustela rixosa rixosa_],
     Proc. Biol. Soc. Washington, 10:21, February 25, 1896, applies to
     the least weasel of Saskatchewan and adjoining areas and as the
     first available name for the species has been used as the specific
     name for the species in America since 1896.

     1897. =paraensis= (_Putorius (Mustela) braziliensis_) Goeldi [=
     _Mustela africana africana_], Zool. Jahrb., abt. f. systematik,
     geogr. u. biol., 10:560, pl. 21, September 15, 1897, a synonym for
     the weasel of the lower Amazon area.

     1898. =neomexicanus= (_Putorius frenatus_) Barber and Cockerell [=
     _Mustela frenata neomexicana_], Proc. Acad. Nat. Sci.
     Philadelphia, p. 188, May 3, 1898, applies to the long-tailed
     weasel of New Mexico, Arizona, Durango and adjoining areas.

     1898. =haidarum= (_Putorius_) Preble [= _Mustela erminea
     haidarum_], Proc. Biol. Soc. Washington, 12:169, August 10, 1898,
     applies to the ermine of the Queen Charlotte Islands, British
     Columbia.

     1899. =notius= (_Putorius noveboracensis_) Bangs [= _Mustela
     frenata noveboracensis_], Proc. New England Zoöl. Club, 1:53, June
     9, 1899, was applied to the long-tailed weasel of the Carolinas
     until 1936 since which time it has been regarded as a synonym of
     _noveboracensis_.

     1899. =occisor= (_Putorius_) Bangs [= _Mustela frenata occisor_],
     Proc. New England Zoöl. Club, 1:54, June 9, 1899, applies to the
     long-tailed weasel of central and northern Maine. Until 1936,
     occisor was ordinarily used as the name of a full species but
     since then has been arranged as a subspecific name under _Mustela
     frenata_.

     1899. =mundus= (_Putorius xanthogenys_) Bangs [= _Mustela frenata
     munda_], Proc. New England Zoöl. Club, 1:56, June 9, 1899, is now
     applied, and generally has been since 1899, to the long-tailed
     weasel of the coastal district of California north of San
     Francisco Bay.

     1899. =muricus= (_Putorius (Arctogale)_) Bangs [= _Mustela erminea
     muricus_], Proc. New England Zoöl. Club, 1:71, July 31, 1899,
     applies to the diminutive ermine, often erroneously designated
     least weasel, of the western United States.

     1899. =oribasus= (_Putorius (Arctogale) longicauda_) Bangs [=
     _Mustela frenata oribasus_], Proc. New England Zoöl. Club, 1:81,
     December 27, 1899, applies to the long-tailed weasel of the Rocky
     Mountains northward from Yellowstone National Park.

     1900. =eskimo= (_Putorius rixosus_) Stone [= _Mustela rixosa
     eskimo_], Proc. Acad. Nat. Sci. Philadelphia, 1900:44, March 24,
     1900, is applied to the least weasel of Alaska and adjacent parts
     of boreal North America.

     1901. =allegheniensis= (_Putorius_) Rhoads [= _Mustela rixosa
     allegheniensis_], Proc. Acad. Nat. Sci. Philadelphia, 1900:75,
     March 25, 1901, applies to the least weasel of the eastern United
     States.

     1902. =perdus= (_Putorius tropicalis_) Merriam [= _Mustela frenata
     perda_], Proc. Biol. Soc. Washington, 15:67, March 22, 1902,
     applies to the long-tailed weasel of the Lower Tropical Life-zone
     from southern Veracruz into Guatemala.

     1903. =microtis= (_Putorius_) Allen [= _Mustela erminea
     richardsonii_], Bull. Amer. Mus. Nat. Hist., 19:563, October 10,
     1903, is a name applied to an individual ermine of small size from
     Shesley, British Columbia, which Allen thought was specifically
     distinct from the ermine of the Hudsonian Life-zone and adjacent
     territory. Now the name is arranged as a synonym of
     _richardsonii_.

     1904. =audax= (_Putorius_) Barrett-Hamilton [= _Mustela erminea
     arctica_], Ann. and Mag. Nat. Hist., ser. 7, 13:392, May, 1904. In
     the original description the type locality, Discovery Bay, was
     erroneously stated to be in Greenland and the name _audax_ until
     1945 was applied to the kind of weasel occurring in northern
     Greenland whereas the type specimen was taken instead in northern
     Ellesmere Island and because the weasel there is subspecifically
     indistinguishable from ermines from farther west, _audax_ is a
     synonym of _Putorius arcticus_.

     1904. =imperii= (_Putorius arcticus_) Barrett-Hamilton [= _Mustela
     erminea richardsonii_], Ann. and Mag. Nat. Hist., ser. 7, 13:392,
     May, 1904, based on an animal from Fort Simpson, Mackenzie,
     Canada, proves to be inseparable from _richardsonii_ which has
     priority.

     1904. =polaris= (_Putorius arcticus_) Barrett-Hamilton [= _Mustela
     erminea polaris_], Ann. and Mag. Nat. Hist., ser. 7, 13:393, May,
     1904, is the name used for the ermine of eastern Greenland and
     since 1945 has been used for the weasel of Greenland as a whole.

     1905. =macrophonius= (_Putorius_) Elliott [= _Mustela frenata
     macrophonius_], Proc. Biol. Soc. Washington, 18:235, December 9,
     1905, applies to the long-tailed weasel of the mountains along the
     eastern border of Veracruz.

     1906. =leptus= (_Putorius streatori_) Merriam [= _Mustela erminea
     murica_], Proc. Biol. Soc. Washington, 16:76, May 29, 1903, until
     1945 was applied to the diminutive ermine of the Rocky Mountains
     from Wyoming south to northern New Mexico but proves to be a
     synonym of _muricus_ with type locality in the Sierra Nevada of
     California.

     1908. =angustidens= (_Putorius cicognanii_) Brown [= _Mustela
     erminea angustidens_], Mem. Amer. Mus. Nat. Hist., 9(pt. 4):181,
     pl. 17, is applied to an extinct subspecies known from fossil
     remains of Pleistocene age from northern Arkansas.

     1908. =gracilis= (_Putorius_) Brown [= _Mustela frenata
     gracilis_], Mem. Amer. Mus. Nat. Hist., 9(pt. 4):182, 1908,
     applies to a Pleistocene weasel known from a single skull from
     northern Arkansas.

     1912. =costaricensis= (_Mustela_) Goldman [= _Mustela frenata
     costaricensis_], Proc. Biol. Soc. Washington, 25:9, January 23,
     1912, applies to the long-tailed weasel of Costa Rica.

     1913. =primulina= (_Mustela_) Jackson [= _Mustela frenata
     primulina_], Proc. Biol. Soc. Washington, 26:123, May 21, 1913,
     applies to the long-tailed weasel of the central part of the
     United States in eastern Kansas and adjoining areas.

     1913. =campestris= (_Mustela_) Jackson [= _Mustela rixosa
     campestris_], Proc. Biol. Soc. Washington, 26:124, May 21, 1913,
     applies to the least weasel of the Great Plains region.

     1913. =olivacea= (_Mustela peninsulae_) Howell [= _Mustela frenata
     olivacea_], Proc. Biol. Soc. Washington, 26:139, May 21, 1913,
     applies to the long-tailed weasel of the southeastern United
     States excepting most of Florida.

     1914. =meridana= (_Mustela_) Hollister [= _Mustela frenata
     meridana_], Proc. Biol. Soc. Washington, 27:143, July 10, 1914,
     applies to the long-tailed weasel of northern South America.

     1916. =nicaraguae= (_Mustela tropicalis_) Allen [= _Mustela
     frenata nicaraguae_], Bull. Amer. Mus. Nat. Hist., 35:100, April
     28, 1916, applies to the long-tailed weasel of Nicaragua.

     1927. =arthuri= (_Mustela noveboracensis_) Hall [= _Mustela
     frenata arthuri_], Proc. Biol. Soc. Washington, 40:193, December
     2, 1927, applies to the long-tailed weasel of Louisiana and
     adjoining areas.

     1932. =semplei= (_Mustela arctica_) Sutton and Hamilton [=
     _Mustela erminea semplei_], Ann. Carnegie Mus., 21(2):79, February
     13, 1932, originally was applied to the ermine of Southampton
     Island but after 1945 was applied also to the ermine of Baffin
     Island, Melville Peninsula and the west side of Hudsons Bay as far
     south as Eskimo Point.

     1932. =panamensis= (_Mustela frenata_) Hall, Proc. Biol. Soc.
     Washington, 45:139, September 9, 1932, applies to the long-tailed
     weasel of Panamá.

     1932. =anguinae= (_Mustela cicognanii_) Hall [= _Mustela erminea
     anguinae_], Univ. California Publ. Zoöl., 38:417, November 8,
     1932, applies to the ermine of Vancouver Island, British Columbia.

     1935. =labiata= (_Mustela arctica_) Degerbøl [= _Mustela erminea
     semplei_], Rept. 5th Thule Exped., 1921-1924, vol. 2, no. 4, p.
     25, 1935. When Degerbøl wrote his description and proposed this
     name he was unaware that Sutton and Hamilton had three years
     before based a new name on weasels from Southampton Island.
     Because the two names apply to the same subspecies, Degerbøl's
     name, _labiata_, must fall as a synonym of _semplei_ which has
     priority.

     1935. =helleri= (_Mustela frenata_) Hall, Proc. Biol. Soc.
     Washington, 48:143, August 22, 1935, applies to the long-tailed
     weasel of eastern Perú.

     1936. =nevadensis= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 91, November 20, 1945, applies to
     the long-tailed weasel of the western United States. For many
     years, animals of this subspecies were referred to _longicauda_
     and from 1891 until 1936 to _arizonensis_.

     1936. =effera= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 93, November 20, 1945, applies to
     the long-tailed weasel of the Blue Mountains region. From 1891
     until 1936 this animal was referred to under the name
     _arizonensis_.

     1936. =altifrontalis= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 94, November 20, 1936, applies to
     the long-tailed weasel of the humid coastal district from Puget
     Sound southward into Oregon.

     1936. =nigriauris= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 95, November 20, 1936, applies to
     the long-tailed weasel of the coastal district of California from
     San Francisco Bay southward to Point Concepcion. Previous to 1936,
     _xanthogenys_ was the name applied to this race of weasel.

     1936. =latirostra= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 96, November 20, 1936, applies to
     the long-tailed weasel of southern California which previously had
     borne the name _xanthogenys_.

     1936. =pulchra= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 98, November 20, 1936, is applied to
     the long-tailed weasel of the southern end of the San Joaquin
     Valley of California.

     1936. =inyoensis= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 99, November 20, 1936, is applied to
     the long-tailed weasel of Owens Valley, California.

     1936. =texensis= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 99, November 20, 1936, applies to
     the long-tailed weasel of central Texas which previously had been
     assigned to the subspecies _frenata_.

     1936. =perotae= (_Mustela frenata_) Hall, Carnegie Inst.
     Washington, publ. no. 473, p. 100, November 20, 1936, applies to
     long-tailed weasel of the mountains along the Puebla-México
     boundary.

     1938. =boliviensis= (_Mustela frenata_) Hall, Proc. Biol. Soc.
     Washington, 51:67, May 18, 1938, applies to the southernmost known
     long-tailed weasel which is in the Lake Titicaca region in Perú
     and Bolivia.

     1944. =salva= (_Mustela erminea_) Hall, Proc. Biol. Soc.
     Washington, 57:35, June 28, 1944, applies to the ermine of
     Admiralty Island, southeastern Alaska.

     1944. =initis= (_Mustela erminea_) Hall, Proc. Biol. Soc.
     Washington, 57:37, June 28, 1944, applies to the ermine of Baranof
     and Chichagof islands, southeastern Alaska.

     1944. =celenda= (_Mustela erminea_) Hall, Proc. Biol. Soc.
     Washington, 57:38, June 28, 1944, applies to the ermine of Prince
     of Wales, Dall and Long islands, Alaska.

     1944. =seclusa= (_Mustela erminea_) Hall, Proc. Biol. Soc.
     Washington, 57:39, June 28, 1944, applies to the ermine of Suemez
     Island, southeastern Alaska.

     1945. =invicta= (_Mustela erminea_) Hall, Jour. Mamm., 26:75,
     February 27, 1945, applies to the ermine of the Rocky Mountains
     for several hundred miles both north and south of the United
     States-Canadian boundary.

     1945. =fallenda= (_Mustela erminea_) Hall, Jour. Mamm., 26:79,
     February 27, 1945, applies to the ermine of the coastal mainland
     in southern British Columbia and northern Washington.

     1945. =olympica= (_Mustela erminea_) Hall, Jour. Mamm., 26:81,
     February 27, 1945, applies to the diminutive ermine of the Olympic
     Peninsula, state of Washington.

     1945. =gulosa= (_Mustela erminea_) Hall, Jour. Mamm., 26:84,
     February 27, 1945, applies to the diminutive ermine of the
     Cascades in Washington.

     1945. =bangsi= (_Mustela erminea_) Hall, Jour. Mamm., 26:176, July
     19, 1945, is the name applied today to the ermine of the western
     Great Lakes region.

In 1925 when this study was begun, the American weasels (subgenus
_Mustela_ proper) were arranged as belonging to 47 kinds (including
subspecies) of 29 full species. In the present account a total of 68
kinds, belonging to 4 full species are recognized in the subgenus
_Mustela_. The increase in number of subspecies and the decrease in
number of species are the nomenclatural results ordinarily obtained in
this decade from a systematic study of a genus of American mammals.



CHECK-LIST OF AMERICAN SPECIES AND SUBSPECIES OF THE GENUS MUSTELA

Subgenus =MUSTELA= Linnaeus


                                                              PAGE
  _Mustela erminea_                                             87
  _Mustela erminea arctica_ (Merriam)                           96
  _Mustela erminea polaris_ (Barrett-Hamilton)                 103
  _Mustela erminea semplei_ Sutton and Hamilton                105
  _Mustela erminea kadiacensis_ (Merriam)                      108
  _Mustela erminea richardsonii_ Bonaparte                     110
  _Mustela erminea cicognanii_ Bonaparte                       118
  _Mustela erminea bangsi_ Hall                                124
  _Mustela erminea invicta_ Hall                               128
  _Mustela erminea alascensis_ (Merriam)                       131
  _Mustela erminea salva_ Hall                                 135
  _Mustela erminea initis_ Hall                                136
  _Mustela erminea celenda_ Hall                               139
  _Mustela erminea seclusa_ Hall                               141
  _Mustela erminea haidarum_ (Preble)                          142
  _Mustela erminea anguinae_ Hall                              145
  _Mustela erminea fallenda_ Hall                              148
  _Mustela erminea olympica_ Hall                              153
  _Mustela erminea streatori_ (Merriam)                        155
  _Mustela erminea gulosa_ Hall                                159
  _Mustela erminea muricus_ (Bangs)                            161
  _Mustela erminea angustidens_ (Brown)                        165

  _Mustela rixosa_                                             168
  _Mustela rixosa eskimo_ Stone                                181
  _Mustela rixosa rixosa_ Bangs                                184
  _Mustela rixosa allegheniensis_ Rhoads                       187
  _Mustela rixosa campestris_ Jackson                          190

  _Mustela frenata_                                            193
  _Mustela frenata noveboracensis_ (Emmons)                    222
  _Mustela frenata occisor_ (Bangs)                            230
  _Mustela frenata primulina_ (Jackson)                        232
  _Mustela frenata arthuri_ Hall                               241
  _Mustela frenata olivacea_ Howell                            244
  _Mustela frenata peninsulae_ Rhoads                          250
  _Mustela frenata spadix_ (Bangs)                             252
  _Mustela frenata longicauda_ Bonaparte                       262
  _Mustela frenata oribasus_ (Bangs)                           270
  _Mustela frenata alleni_ (Merriam)                           274
  _Mustela frenata arizonensis_ (Mearns)                       276
  _Mustela frenata nevadensis_ Hall                            280
  _Mustela frenata effera_ Hall                                291
  _Mustela frenata washingtoni_ (Merriam)                      294
  _Mustela frenata saturata_ (Merriam)                         297
  _Mustela frenata altifrontalis_ Hall                         300
  _Mustela frenata oregonensis_ (Merriam)                      304
  _Mustela frenata munda_ (Bangs)                              309
  _Mustela frenata xanthogenys_ Gray                           315
  _Mustela frenata nigriauris_ Hall                            319
  _Mustela frenata latirostra_ Hall                            323
  _Mustela frenata pulchra_ Hall                               328
  _Mustela frenata inyoensis_ Hall                             331
  _Mustela frenata neomexicana_ (Barber and Cockerell)         333
  _Mustela frenata texensis_ Hall                              338
  _Mustela frenata frenata_ Lichtenstein                       341
  _Mustela frenata leucoparia_ (Merriam)                       347
  _Mustela frenata perotae_ Hall                               351
  _Mustela frenata goldmani_ (Merriam)                         355
  _Mustela frenata macrophonius_ (Elliot)                      360
  _Mustela frenata tropicalis_ (Merriam)                       363
  _Mustela frenata perda_ (Merriam)                            366
  _Mustela frenata nicaraguae_ Allen                           370
  _Mustela frenata costaricensis_ Goldman                      372
  _Mustela frenata panamensis_ Hall                            375
  _Mustela frenata meridana_ Hollister                         379
  _Mustela frenata affinis_ Gray                               384
  _Mustela frenata aureoventris_ Gray                          387
  _Mustela frenata helleri_ Hall                               391
  _Mustela frenata agilis_ Tschudi                             393
  _Mustela frenata macrura_ Taczanowski                        398
  _Mustela frenata boliviensis_ Hall                           402
  _Mustela frenata gracilis_ (Brown)                           404


Subgenus =Grammogale= Cabrera

  _Mustela africana_                                           406
  _Mustela africana africana_ Desmarest                        409
  _Mustela africana stolzmanni_ Taczanowski                    413


Subgenus =Putorius= Cuvier

(Black-footed Ferret--not treated in present work)

  _Mustela nigripes_ (Audubon and Bachman)


Subgenus =Lutreola= Wagner

(Minks--not treated in present work)

  _Mustela vison_
  _Mustela vison vison_ Schreber
  _Mustela vison mink_ Peale and Beauvois
  _Mustela vison lutensis_ (Bangs)
  _Mustela vison evergladensis_ Hamilton
  _Mustela vison vulgivaga_ (Bangs)
  _Mustela vison letifera_ Hollister
  _Mustela vison lacustris_ (Preble)
  _Mustela vison energumenos_ (Bangs)
  _Mustela vison evagor_ Hall
  _Mustela vison aestuarina_ Grinnell
  _Mustela vison nesolestes_ (Heller)
  _Mustela vison melampelus_ (Elliot)
  _Mustela vison ingens_ (Osgood)
  _Mustela macrodon_ (Prentiss)



ARTIFICIAL KEY TO AMERICAN SPECIES OF THE GENUS MUSTELA


                                                                   PAGE

  A Length of upper tooth-rows less than 20 mm. in males and
    17.8 mm. in females.

      B  Postglenoid length of skull more than 47 per cent of
         condylobasal length.

          C  Tail without a black pencil and with at most a few
             black hairs at extreme tip; in both sexes mastoid
             breadth ordinarily exceeds breadth of braincase,
                                 _Mustela rixosa_, least weasel, p. 168

          C' Tail with a black pencil; in females mastoid breadth
             ordinarily exceeded by breadth of braincase,
                                      _Mustela erminea_, ermine, p.  87

      B' Postglenoid length of skull less than 47 per cent of
  condylobasal length.

          D  Tail with distinct black tip; midventral line white,
             yellowish, orange, not same color as upper parts; p2
             present; thenar pad on forefoot absent,
                          _Mustela frenata_, long-tailed weasel, p. 193

          D' Tail without black tip; midventral line same color
             as upper parts; p2 absent; thenar pad on forefoot
             present,
                            _Mustela africana_, tropical weasel, p. 406

  A' Length of upper tooth-rows more than 20 mm. in males and
     17.8 mm. in females.

      E  Abdomen all white; face with blackish mask; m1 lacking
         even a trace of a metaconid; distance between upper
         canines more than width of basioccipital as measured
         between foramina situated midway along medial sides of
         tympanic bullae,
                        _Mustela nigripes_, black-footed ferret.

      E' Abdomen dark brown, like back; face uniformly brown
         without blackish mask; m1 with incipient metaconid;
         distance between upper canines less than width of
         basioccipital as measured between foramina situated
         midway along medial sides of tympanic bullae,
                           _Mustela vison_, mink, American mink.



DIAGNOSIS OF THE GENUS

Genus =Mustela= Linnaeus

Weasels, Ferrets, Polecats, Minks


_Genotype._--_Mustela erminea_ Linnaeus.

_Diagnosis._--Legs short; body relatively long; adults 190 mm. to 700
mm. in total length; skull ranging in basilar length from 16 to 70 mm.;
facial angle slight; tympanic bullae greatly inflated (moderately in
_Lutreola_), cancellous, and with paroccipital processes closely
appressed to bullae; palate behind upper molars; dental formula:

  I  3  C  1  P  2-3  M  1
  -, -; -, -; -, ---; -, -; inner moiety of M1 larger than outer; P4
  i  3  c  1  p  3-2  m  2

with simple deuterocone; in m1 inner moiety of M1 larger than outer; P4
with simple deuterocone; in m1 trigonid longer than talonid, metaconid
absent (incipiently developed in _Lutreola_), and talonid trenchant.

For many years prior to 1911, the name _Mustela_ was applied to
martens, and _Putorius_ was regarded as the first available generic
name for the weasels. In 1911 Thomas (1911:139) showed that _M.
erminea_ (_Mustela_ of Gesner) by tautonymy was the type of _Mustela_
and subsequently the generic name _Mustela_ has been used for the true
weasels which include the American weasels to which we now apply the
specific names _erminea_, _rixosa_ and _frenata_. The mink, _Mustela
(Lutreola) vison_, and the black-footed ferret, _Mustela (Putorius)
nigripes_, since 1911 also have been referred by most American authors
to the genus _Mustela_, the names _Lutreola_ and _Putorius_ being
regarded by these authors as having no more than subgeneric status.
European writers, on the other hand, accord greater taxonomic weight to
the zoölogical differences between ferrets and weasels and, therefore,
accord full generic rank to _Putorius_. Consequently, for the
black-footed ferret, Europeans today write _Putorius nigripes_ and
Americans write _Mustela nigripes_. For the same reasons, the name of
the mink is written by some European zoölogists _Lutreola vison_ and by
American zoölogists _Mustela vison_.



EXPLANATION OF SYSTEMATIC TREATMENT


For each full species there will be found under the account of it the
following information: Type, statement of geographic range, selected
characters for ready recognition, other characters of the species, a
summary of geographic variation, and information on habits, in the
order mentioned.

For each subspecies, information is presented in the following order:
earliest available zoölogical name, synonyms, type, geographic range,
zoölogical characters for ready recognition, description (mentioning
size, certain external features including color, the skull and teeth)
historical material when warranted, remarks which may elaborate on
points made in preceding paragraphs, and other information thought to
be useful, and finally a list of specimens examined.

In explanation of certain of these categories it should be said that in
the synonymy no attempt is made to list every published reference to
the subspecies concerned. It is aimed, however, to include at least one
citation to each name-combination that has been applied, to the
subspecies concerned, along with other especially important references.
Mere records of occurrence are not regarded as especially important and
citations to them ordinarily are omitted in the synonymy. No comma is
placed between the zoölogical name and the name of the author who
coined and first used the name in accordance with the rules of
zoölogical nomenclature. Otherwise a comma is interposed between the
zoölogical name and the name of the user (author). When the accepted
(earliest available) name of a subspecies at the head of any one of the
following accounts is combined with a generic name different from that
with which it originally was placed, the authority for the name is set
in parentheses. The same rule is followed with the name of a full
species when it is written without any subspecific name following.
Parentheses in such situations, therefore, denote that for the terminal
part of the scientific name there has been a change in generic name
with which the terminal part of the scientific name is here associated.

In the paragraph headed "characters for ready recognition," only a few
characters, namely, those regarded as most useful for identification
when the student has limited time, are mentioned. Other features useful
for distinguishing the kind of animal in question from its near
relatives are to be found in the description and comparisons.

In the description, external measurements, unless otherwise indicated,
are those recorded by the collector on the label attached to the skin.
Total length is the distance from the tip of the pad on the nose to the
tip of the fleshy part of the tail when the relaxed animal is laid out
straight, not stretched. This measurement does not include the hairs
that project beyond the end of the fleshy part of the tail. Length of
tail is the distance from the base of the tail, when it is bent at
right angles to the long axis of the body, to the tip of the fleshy
part of the tail excluding the hairs that project beyond the fleshy
part of the tail. Length of tail and length of tail-vertebrae are
synonymous. Length of hind foot is measured from the proximal end of
the calcaneum to the tip of the longest claw.

Capitalized color terms, unless otherwise indicated, refer to Ridgway's
(1912) _Color Standards and Color Nomenclature_. Some use is made of
color terms taken from Oberthür and Dauthenay (1905) because those
authors show a much larger number of shades between dark brown and
black than does Ridgway (1912). The colors of the upper parts of most
weasels are some shade or other of dark brown. Color terms that do not
have the initial letter capitalized do not refer to any one standard
and consequently are used in a general sense.

Relative extents of the color of the upper parts and underparts are
computed from measurements of the circumference of the body at the
place where the color of the underparts is narrowest. Ordinarily this
place is in the lumbar region rather than in the thoracic region.

An explanation of how cranial measurements were taken is given on page
417. In designating teeth, capital letters are used for teeth in the
upper jaw and lower case letters are used for teeth in the lower jaw.
For example: I2 denotes the second incisor tooth in the upper jaw and
i2 denotes the second incisor tooth in the lower jaw; C1 and c1 refer
to the canine tooth of the upper jaw and lower jaw, respectively; P3
and p3 refer to the third premolar of the upper jaw and lower jaw,
respectively, bearing in mind that the first (anterior) premolar is
absent in the lower jaw and upper jaw of weasels (see fig. 31 on page
416), as also, in some kinds of weasels, is the second premolar; M1 and
m1 refer to the first molar of the upper jaw and lower jaw
respectively.

In describing the skull and teeth the two sexes are treated separately
because differences in shape as well as size are the rule. Unless
otherwise indicated, the skulls on which descriptions are based are of
adults. Weights of skulls include the weight of the lower jaws. In
general, every second subspecies is described. For a subspecies
geographically next adjacent to the one described, only the
differences between the two are enumerated. This method of description
indicates also likenesses and is more economical of words than some
other methods of description. Also, by use of this method, cross
reference is reduced to one other subspecies. Following this formal
description, there is a comparison of the cranial and dental characters
with those of geographically adjacent subspecies.

In the paragraph headed "Remarks" the two words "character" and
"structure" frequently appear. The word structure here is used to mean
some part of an animal, as for example, a hair, a muscle, a bone, or an
internal organ. A structure is not a system, as for example, the
digestive system or osseous system. A character is some weight, linear
dimension, volume, shape, color, or other perceptible attribute of a
structure, of a system, or of an entire organism.

In recording the localities of capture of specimens examined, effort
has been made to be exactly as precise as the locality data on the
labels of the specimens permit. The word "County" is written out in
full when the name of the county is written on the label of each
specimen listed from that county. When one specimen, or more, here
assigned to a given county lacks the name of the county on the label,
then the abbreviation "_Co_." is used. The surprising frequency with
which the same place name is repeated in a given state or province
makes it desirable for the collector to write the name of the county,
or corresponding minor political subdivision, on labels of study
specimens at the time they are prepared.



SYSTEMATIC ACCOUNTS OF SPECIES AND SUBSPECIES


=MUSTELA ERMINEA= Linnaeus

Ermine

(Synonymy under subspecies)

     _Type._--_Mustela erminea_ Linnaeus, Systema Naturae, 10th ed., p.
     46, 1758.

     _Range._--From the British Isles and Atlantic Coast of Europe
     across Eurasia and North America including Greenland, from the
     northernmost land, south, in North America, to the lower margin of
     the Canadian Life-zone; geographically south to Connecticut, New
     York, Pennsylvania, northeastern Ohio, southern Michigan,
     Wisconsin, northern Iowa, Minnesota, North Dakota, in the Rocky
     Mountains to northern New Mexico, in the Sierra Nevada to Mono
     County, California, and on the Pacific Coast to the Golden Gate.

_Characters for ready recognition._--Differs from _Mustela rixosa_ in
presence of black pencil on tail, tail-vertebrae more than a fourth of
length of head and body, and in regions where the two species occur
together, basilar length of skull more than 32.5 in males and more than
31.0 in females; from _Mustela frenata_, in regions where the two
species occur together, by tail less than 44 per cent of length of head
and body and by postglenoidal length of skull more than 46 per cent of
condylobasal length in males and more than 48 per cent in females.

_Characters of the species._--Size medium to small (total length 225 to
340 mm. in males and 190 to 290 mm. in females); tail 30 to 45 per cent
of length of head and body, with distinct black pencil; caudal
vertebrae 16 to 19; skull with long braincase and short precranial
portion; postglenoidal length, when expressed as a percentage of the
condylobasal length, more than 48 in females and ordinarily more than
46 in males; upper parts brown; underparts whitish, ordinarily
continuous from chin to inguinal region but in subspecies in the humid
region along the Pacific Coast interrupted in some individuals by brown
of upper parts encircling body in the abdominal region. The soles of
the feet in each of the subspecies are densely haired in winter and
have only a relatively small area of the foot-pads exposed in summer,
the intervening areas being well haired even at that season. The
uniformity throughout the species as regards hairiness of the
foot-soles and also the character of the vibrissae makes it unnecessary
to describe these features in the accounts of the subspecies of
_erminea_.

_Geographic variation._--In the Old World 16 or more subspecies are
currently recognized and there are 20 in North America. The features in
which geographic variation is especially prominent are: First, size,
as expressed by external measurements and weight, second, color
pattern, depending on the extent, in relation to one another, of the
dark-colored upper parts and light-colored underparts, and third,
breadth and depth of the rostral region of the skull. Except in size,
the variation in the skull is less than in _M. frenata_. Likewise in
tone and shade of upper parts and hue or tint of underparts, _erminea_
is less variable than _frenata_ and has the face all of one color
without the contrasting color-pattern of the face and head seen in many
subspecies of _frenata_. _M. erminea_ exceeds _frenata_ as regards
variation of the size of the area occupied by the light-colored
underparts. At one extreme is the subspecies _arctica_ in which the
area of the light color extends well up on the sides of the body, down
the insides of the legs, over the feet and far out on the lower side of
the tail whereas at the other extreme are the races _streatori_ and
_olympica_ in which the light-colored underparts are restricted to two
areas, one on the chin, throat and chest, and the other on the inguinal
region. These areas may or may not be connected by a thin line of white
color along the midline of the underparts. In size of animal, _erminea_
probably exhibits the maximum variation among American species of
weasels; an average-sized male of the race _arctica_ weighs 4 times as
much as one of the race _muricus_, and in the species _frenata_ I doubt
that the difference is quite as great between individuals of the
smallest race, _effera_, on the one hand, and either of the largest
races, _texensis_ or _macrophonius_, on the other hand although actual
weights are not available for these races of _frenata_. As elsewhere
indicated, the small-sized individuals of _M. erminea_ are of the
southern races and the large-sized individuals are of the northern
races. This decrease in size southward occurs both in Asia and in
America.

_Natural history._--habitat and numbers.--Along the International
Boundary east of the Turtle Mountains, Soper (1946:136) found this
species present only in timbered areas and absent from many untimbered
areas. Of the same species to the westward he comments "so far as I
know at present, there is no evidence to show that any short-tailed
weasels inhabit a broad strip of treeless territory immediately north
of the International Boundary in Canada from southwestern Alberta to
southeastern Saskatchewan." The same author (1942) reports that in the
general area of Wood Buffalo Park, Northwest Territory, south of Great
Slave Lake, the ermine is uncommon on pine-grown sand ridge and rolling
upland and common in lower spruce-aspen parklands, stream-side
coniferous belts, and grassy, semi-wooded swamplands.

Nine ermines per square mile is the number that Soper (1919:46-47)
estimated at Edmonton on the basis of the numbers that he trapped there
in the winters of 1912-13 and 1913-14 and on the basis of the tracks of
remaining ermines. From corresponding data he estimated the population
in the winter of 1913 on the Hay River, north of Jasper Park, to be
nine per square mile. In each of these instances he estimated ten
weasels per square mile but he inclined to the view that one-tenth of
the animals involved in his counts were long-tailed weasels (_Mustela
frenata_). Osgood (1909B:30) and his field companion in the period July
31 to September 3, 1903, took a series of 42 specimens within a radius
of 500 yards of their camp at the head of Seward Creek, Alaska, all
caught in four traps, in one month. Of the 42 specimens, 28 are males
and 14 are females.

Fluctuations of a multiannual nature are marked in this species. Bailey
(1929:156) observes that in Sherburne County, Minnesota, when meadow
mice are abundant for two or three years these weasels become abundant
but that when the mice are scarce the weasels also become scarce.
Manning (1943:56), on Southampton Island, noted "that the maximum and
minimum points of the weasel cycle are much more sharply marked than
those of the fox cycle and the increase and decrease are more rapid."

How far an ermine will travel in a given length of time has seldom been
recorded but Hamilton (1933:293), on March 20, 1932, "followed the
track of a small weasel, presumably a male _cicognanii_, for four miles
in the fresh snow," and Ingles (1942) observed a diminutive ermine of
the subspecies _M. e. muricus_, at Woods Lake, California, 286 yards
from its den.


Behavior

As regards locomotion, Soper (1919:46), in reference to _Mustela
cicognanii_, presumably in Ontario, Canada, writes that in the bounding
gait the hind feet register almost, if not exactly, in the front-foot
impressions, with the right front and hind feet lagging slightly
behind. "The distance normally is about 19 inches, representing a
regular rate of travel. . . . In traversing open spaces they resort to
long, graceful leaps upwards of six feet in length. . . . I measured a
record . . . of 8 feet, 2 inches."

Of _M. e. arctica_, Dice (1921:22) writes that when it runs "the tail
is carried off the ground usually at an angle of about 45 degrees."
Seton (1929 (2):598) states that "At Carberry [Manitoba] I have often
seen this energetic little creature seeking for Mice in the deep, soft
snow. Its actions are much like those of an Otter pursuing salmon.
Sometimes it gallops along a log, or over an icy part of the drift;
then plunges out of sight in a soft place, to reappear many yards
away. . . ."

Little is recorded concerning swimming but on this score Seton (1929
(2):602) does quote J. W. Curran, who in July, 1899, at Lake
Couchiching, Ontario, watched an ermine pursue a chipmunk into the
water and for 100 yards before giving up the chase and wheeling around
and making for shore. In swimming "The Weasel, I think, showed more of
his body, and seemed to exert himself more" than the chipmunk.

As to voice, Dice (1921:22), at Tanana, Alaska, heard the ermine, when
excited, bark somewhat like a mink but not so loud and Seton (1929
(2):606) quotes Manley Hardy to the effect that the species has a
purring note.

Sense of smell was used by an _M. e. muricus_ that Dixon (1931:72)
watched as the ermine followed a three-fourths-grown pika. Concerning
the ermine at Carberry, Manitoba, Seton (1929 (2):598-599) writes that
"The smell of blood must be as far-reaching as it is attractive to
these sanguinary little creatures. I have frequently hung new-killed
Rabbits and partridges temporarily in trees, and, after an absence, in
some cases of a few minutes only, have found an Ermine mauling the
game, though there was no sign of such a visitor when the cache was
made."


Enemies

George Measham, of Winnipeg, found sign in the snow indicating that a
great snowy owl had killed an ermine and T. McIlwraith shot a bald
eagle at Hamilton Bay which had the bleached skull of a weasel
(probably of this species) clinging to the throat (Seton, 1929
(2):603).

A. B. Howell (1943:98) likens mustelid mammals to domestic cats in
their manner of crossing roads and thinks that mustelids loiter at the
side of the road until the stimulus of the approaching car causes them
to make a dash whereupon they are caught by the wheels and killed.
Three of four weasels seen to cross the road were killed, one even
having apparently crossed the road before turning back and being killed
under the car. One weasel killed was _Mustela erminea cicognanii_.
Dalquest (1948:190) in writing of this species in the state of
Washington, says "I have seen only one abroad in the daytime. It dashed
from a roadside thicket . . . and was crushed beneath the wheels of a
car."


Food

The killing of prey is described by Hamilton (1933:332) as follows: "A
rapid dash, and the bird or mouse is grabbed over the back of the
skull, the fore legs encircle the animal as though hugging it, and the
hind legs are brought up to scratch wildly at the captive. . . . If
[the prey is] a large animal, as a rat, the weasel usually lies on its
side, while the diminishing struggles of the rodent continue, but if a
mouse or a small bird [is the object of attack], the weasel is apt to
crouch over its prey. Little time is lost over the first [mouse] . . .
if two mice are present [;] a strong bite through the brain case . . .
[is] sufficient. If only one animal is present, the weasel dawdles over
its kill some time after life has departed."

Hamilton's (1933:333) study of the contents of the digestive tracts of
bodies of ermines obtained from fur trappers and fur buyers in New York
enabled him to publish the following "Frequency Indices of Mammal
Genera in Fall and Winter Food of 191 Mustela cicognanii": _Microtus_,
35.7 per cent; mammals undetermined to genus but principally mice,
16.3; _Blarina_, 15.1; _Peromyscus_, 11.4; _Sylvilagus_, 9.0; _Sorex_,
4.9; _Rattus_, 4.4; _Tamias_, 3.6. Close correspondence is shown by the
following data of Aldous and Manweiler (1942) for the ermine from Lake
of the Woods, Minnesota: mice, 58.7 per cent by number and 54.5 by
volume; shrews 22.5 and 21.8 per cent; birds, 2.7 and 5.0 per cent. Of
the mice in stomachs, 40 per cent were microtines, 15 per cent were
_Peromyscus_ and 45 per cent were unidentified as to kind. Fragments of
a small fish were found in one stomach. Summed up, the dominant winter
foods were mice and shrews. Trapping of the mammal populations was done
to see what the available food was and it was found that the small
mammals were eaten in direct ratio to their relative abundance.
Snowshoe rabbits and red squirrels were not eaten. The Minnesotan data
were from 60 stomachs and 53 intestinal tracts recovered from 129
weasels trapped by use of scent (not bait) mostly from January 1 to
February 7, 1939, although a few were trapped in 1938. Analyses of
contents from stomachs gave approximately the same results as those
from intestines. In 1939 at Lake of the Woods, weasels were
concentrated where food was abundant but no such concentration was
noted in the following winter.

Big short-tailed shrew (_Blarina brevicauda_).--In New York State, the
ermine preys on _Blarina_ as shown by Hamilton's (1933:330) seeing one
being carried by a male ermine on May 6, 1931, and another being
carried by a female on May 13, 1932. The same author (1928:249) found
the remains of a _Blarina_ in a small female from Malone, New York.
Kirk (1921) observed, however, that the ermine (_M. e. cicognanii_)
avoided the shrew, _Blarina_, caught in a trap and that _Blarina_
avoided the weasel caught in a trap.

Chipmunk (genus _Tamias_).--Remains were found in a male ermine in New
York on May 14, 1932 (Hamilton, 1933:330), and Seton (1929 (2):602)
records a chipmunk at Lake Couchiching, Ontario, that was pursued into
the water by an ermine.

Deer mice (genus _Peromyscus_).--As shown by Hamilton (1933:33) and
Aldous and Manweiler (1942), _Peromyscus_ was second only to microtines
in numerical abundance among the food items of ermines in New York and
Minnesota. _Peromyscus_ and microtine rodents were brought to a den of
the diminutive _M. e. muricus_ in early August, in Fresno County,
California, according to Ingles (1942). He observed that an Alpine
chipmunk was active under and around the tree and that juncos reared
young 40 feet from the den but that the chipmunk and juncos were
unmolested by the ermines.

Lemming (genus _Lemmus_).--One was recovered from a female ermine (with
milk in her glands) at Laurier Pass, British Columbia (Sheldon,
1932:201).

Red-backed mouse (genus _Clethrionomys_).--Criddle and Criddle
(1925:146) record that on "May 31, 1921.--Saw a Bonaparte's weasel
capture a Red-backed Vole after a long hunt during which the pursuer
never once lost track of its victim."

Meadow mice (genus _Microtus_).--As shown by the data of Hamilton
(1933:333) and Aldous and Manweiler (1942) recorded above, _Microtus_
is the item of first importance in the diet of the ermine in New York
and Minnesota. Criddle and Criddle (1925:146) write concerning the
vicinity of Treesbank, Manitoba, that "October, 1918.--Following a
severe outbreak of mice in 1916-17, Bonaparte's weasel increased
enormously and very soon reduced the rodents to comparative rarity.
This resulted in a scarcity of food for the weasels, which in their
turn became greatly reduced in numbers."

Old World rat (_Rattus_).--Bishop (1923) found two headless rats near a
nest of this species in Albany, New York.

Pika (_Ochotona_).--Dixon (1931:72) at Milner Pass, Colorado, on July
20, 1931, saw an ermine, of the subspecies _muricus_, following a
three-fourths grown pika by scent and outrunning the pika. The pikas
worked a relay system and the weasel abandoned the trail when the
fourth pika became the object of the chase.

Cottontail (genus _Sylvilagus_).--Hamilton (1933:33), as noted above,
found remains of cottontail in the digestive tracts of ermine that had
been trapped for fur in winter. Possibly these remains were bait that
had been placed at traps.

Snowshoe rabbit (_Lepus americanus_).--Morse (1939:210) in a study of
predation on hares and grouse in the period of notable decimation of
these two game species in 1935-1936 in the Cloquet Valley State Forest,
in St. Louis County, Minnesota, found that "weasel predation on hares
appeared to be of very low incidence or altogether lacking."

Wild birds (Class Aves).--Aldous and Manweiler (1942), as noted above,
found that the remains of birds constituted five per cent by volume of
the food of the ermine in winter in Minnesota.

Chicken (genus _Gallus_).--Criddle and Criddle (1925:145), who
published relatively extensive data on the three species of weasels of
Manitoba, write that: "We have no record of Bonaparte's weasel killing
poultry, and we doubt whether it ever does so." However, Soper
(1919:46) investigated the excited cackling of a hen brooding chicks at
night and found a solitary ermine that had killed three chicks and that
had the remainder under very active scrutiny.

Leopard frog (_Rana pipiens_).--One frog was found in a male ermine on
November 20, 1931, in New York by Hamilton (1933:300).

Fish (Class Pisces).--Aldous and Manweiler (1942) found fragments of a
small fish in one of 60 stomachs of ermine from Minnesota.

Earthworm (Phylum Annelida).--Osgood (1936:64), presumably at Rutland,
Vermont, observed a pair of weasels from 2:15 P.M. to 5:00 P.M., in a
barn and saw the female in that time make many trips for food for her
young. Only earthworms were brought. Fifty traps in an adjacent, swampy
field caught only one bull frog and no mice indicating that mice had
been eliminated from the foraging territory of the ermine.

In handling food, Dice (1921:22) noted that the Alaskan ermine did not
use the feet but only the mouth.


Reproduction

Litters of 4, 4, 7, 7, and 8, yielding an average of 6 young per litter
have been recorded from the northeastern United States by Hamilton
(1933:327). He (_op. cit._:321-325) described animals one day old from
New York State as being flesh-colored, having the long neck of the
adult and a fine growth of white hair two millimeters in length, on
the dorsal surface of the neck, that foreshadows the mane or pompadour
that is prominent from the 14th to the 21st day of life. Six animals,
when one day old averaged 1.7 grams in weight, which was three per cent
of the weight of an adult female and one and one half per cent of the
weight of an adult male. At two weeks of age the heavy brown mane stood
out in marked contrast to the rest of the scantily, white-furred
animal. The eyes opened on the thirty-fifth day of life.

[Illustration: FIG. 24. _Mustela erminea richardsonii_, adult female,
Catalogue Number 14866, U. S. Nat. Mus., Fort Chimo, Ungava. × 1/2.

Ventral view of body of a pregnant female to show details of mastology.
Note the five pairs of mammae characteristic of weasels, and the uneven
arrangement of mammae of the two sides which is also common among
weasels.]

[Illustration: FIG. 25. Map showing geographic ranges of the subspecies
of _Mustela erminea_ in the New World.]

For rearing their young, ermines live in burrows. Bishop (1923), in
Albany, New York, found a burrow occupied by four young and a pair of
adults. The burrow had many galleries and contained a nest constructed
of rat fur, fine grass and fragments of leaves. At Woods Lake, Fresno
County, California, in early August, Ingles observed (1942) some young
and at least one adult at their den which was in a burrow beneath a
hollow tree. The ermines used the hollow root and the hollow tree as
well as the burrow beneath. Seton (1929 (2):591) quotes S. Eldon
Percival, of Barretts Rapids, Ontario, as finding the living quarters
of an ermine in unthreshed grain stacked in a barn and says (_op.
cit._:590) that John Burroughs dug out a nest, composed of leaves and
the fur of mice and moles, two or three handfuls in bulk, from a cavity
the size of a hat, arched over with a fine network of tree roots.

Four instances in which the male as well as the female was present at a
den containing young are cited by Hamilton (1933:328) and he gives some
evidence, although not at all conclusive, that "adults customarily
pair, or at least run together, at times other than the breeding
season." No other writers remark on this matter. I doubt that adult
ermines are associated in pairs for most of the year but such may be
the case.


=Mustela erminea arctica= (Merriam)

Ermine

Plates 2, 3, 4, 9, 10, 11 and 41

    _Putorius arcticus_ Merriam, N. Amer. Fauna, 11:15, pl. 2, figs. 1,
      1a, and pl. 5, figs. 6, 6a, June 30, 1896.

    _Putorius_ (_Gale_) _erminea_, Coues, Fur-bearing animals, p. 109,
      1877 (part).

    _Putorius richardsonii_, Bangs, Proc. Biol. Soc. Washington, 10:16,
      pl. 1, figs. 3, 3a, pl. 2, figs. 3, 3a, and pl. 3, figs. 6, 6a,
      February 25, 1896 (part).

    _Putorius cicognanii alascensis_, Osgood, N. Amer. Fauna, 19:43,
      October 6, 1900.

    _Putorius kadiacensis_, Osgood, N. Amer. Fauna, 21:69, September
      26, 1901.

    _Putorius audax_ Barrett-Hamilton, Ann. and Mag. Nat. Hist.,
      13(ser. 7):392, May, 1904, type from Discovery Bay, Ellesmere
      Island.

    _Putorius alascensis_, Heller, Univ. California Publ. Zoöl., 5:345,
      March 5, 1910.

    _Mustela arctica arctica_, Miller, U. S. Nat. Mus. Bull., 79:97,
      December 31, 1912; Dice, Journ. Mamm., 2:22, February 10, 1921.

    _Mustela arctica_, Hall, Univ. California Publ. Zoöl., 30:420,
      March 19, 1929.

    _Mustela erminea arctica_, Ognev, The mammals of U.S.S.R. and
      adjacent countries, 3:31, 1935; Hall, Proc. California Acad. Sci,
      23:559, August 22, 1944; Hall, Journ. Mamm., 26:179, July 19,
      1945.

     _Type._--Male, adult, skull and skin; no. 14062/23010, U. S. Nat.
     Mus.; Point Barrow, Alaska; July 16, 1883; obtained by John
     Murdock, original no. 1672.

     The skull has a fracture, on the dorsal surface, extending from
     the anterior nares to the interorbital constriction and another
     fracture on the left margin of the nasal bone. The middle of the
     left zygomatic arch is broken away. Otherwise the skull is
     complete. Right incisor one, above and below, are missing.
     Otherwise the teeth are present and entire. The skin is in the
     brown summer pelage, well made, in a good state of preservation,
     and shows no obvious signs of fading.

     _Range._--Arctic regions of Alaska and western Canada from the
     Pacific Ocean to Smith Sound; from the northern limit of land
     south approximately to a line from Skagway through Ft. Goodhope,
     north shore of Great Bear Lake, south shore of Clinton Colden
     Lake, north shore of Baker Lake, west end of Wagner Bay to south
     end of Committee Bay. See figure 25 on page 95.

     _Characters for ready recognition._--Differs from _M. e. polaris_
     in darker upper parts (Raw Umber rather than Buckthorn Brown) and
     less intensely colored underparts that are Sulphur Yellow,
     Colonial Buff or Primrose Yellow rather than Buff Yellow; from _M.
     e. semplei_, in males, in that hind foot more than 44 and basilar
     length more than 41 and in that females average larger, the skulls
     of females being only about 11 per cent heavier; from _M. e.
     kadiacensis_ in hind foot more than 33 in females, zygomatic
     breadth amounting to more, rather than less, than distance between
     last upper molar and jugular foramen irrespective of sex; from _M.
     e. richardsonii_, _alascensis_, _salva_ and _initis_, both sexes
     so far as known, by proximal two-thirds of under side of tail
     colored same as underparts rather than same as upper parts, and by
     zygomatic breadth amounting to more, rather than less, than
     distance between last upper molar and jugular foramen.

     _Description.--Size._--Male: Six adults from Tanana, Alaska, yield
     average and extreme measurements as follows: Total length, 336
     (310-350); length of tail, 93 (84-105); length of hind foot, 49
     (45-51).

     Female: Five adults, one each from Alatna River, mountains near
     Eagle, Kamarkak in Alaska, Arctic Red River and Baillie Island in
     Canada, yield average and extreme measurements as follows: Total
     length, 285 (272-304); length of tail, 77 (68-95); length of hind
     foot, 39 (34-43).

     Weight of 5 subadult males from Tanana is 206 (163-248) grams;
     adults would be heavier.

     _Color._--Winter pelage all white except tip of tail. Summer
     pelage with upper parts uniform in color and Raw Umber or darker
     (16_n_) of Ridgway and about tones 2 to 3 of Chocolate of Oberthür
     and Dauthenay, pl. 343, but in autumn some specimens have more
     light red than tones 2 or 3. Underparts Sulphur Yellow, Colonial
     Buff, or Primrose Yellow, often white on chin and insides of
     forelegs; color of underparts extends narrowly over upper lips,
     distally on posterior sides of forelegs onto antipalmar surface of
     forefeet, onto proximal two-thirds or three-fourths of underside
     of tail as length of tail is measured along tail-vertebrae, on
     medial sides of hind legs to a point between knee and ankle but
     reappears on antiplantar faces of toes and in some individuals is
     narrowly continuous onto toes; rim of ear in some specimens with
     short, white or pale hairs giving ears distinct whitish border;
     least width of color of underparts averaging, in adult males from
     Alaska, 65 (46-93) per cent of greatest width of color of upper
     parts. Black tip of tail in 5 males in winter pelage from Tanana
     averaging 84 (70-93) mm. which is 91 (75-107) per cent of length
     of tail-vertebrae.

     _Skull._--Male (based on 5 adult topotypes): See measurements and
     plates 2-4. As described in _Mustela erminea richardsonii_ except
     that: Weight, 3.5 (3.1-3.9) grams; basilar length 42.5
     (41.8-43.3); length of tooth-rows more than length of tympanic
     bulla; breadth of rostrum measured across lacrimal processes
     averaging more than a third of basilar length; interorbital
     breadth more than distance between glenoid fossa and posterior
     border of external auditory meatus; zygomatic breadth more than
     distance between last upper molar and jugular foramen.

     Female (based on 2 adult topotypes and 2 adults and 4 subadults
     from central Alaska): See measurements and plates 9-11. As
     described in _Mustela erminea richardsonii_ except that: Weight,
     1.5 (1.2-2.0) grams; basilar length, 35.7 (34.5-37.0); length of
     tooth-rows more than length of tympanic bulla; breadth of rostrum
     more than 30 per cent of basilar length; interorbital breadth more
     than distance between glenoid fossa and posterior border of
     external auditory meatus; zygomatic breadth more than distance
     between last upper molar and jugular foramen (except in specimens
     from Ellesmere Island where two distances are approximately
     equal).

Cranial differences from _Mustela erminea kaneii_ (which occurs on the
Asiatic side of Bering Strait), in both males and females, are: larger
size relatively as well as actually, broader except in mastoidal region
where relatively (to basilar length) the width is less; preorbital part
of skull broader as well as longer.

From _kadiacensis_ differences in the skull of the male are: size less;
13 per cent heavier, relatively (to basilar length) narrower across
interorbital region and zygomatic arches; tympanic bullae relatively as
well as actually narrower. Judging by the single available adult female
of _kadiacensis_, the skull of female _arctica_ is larger in all parts
measured, a fourth heavier, has tympanic bullae of almost twice the
volume and the interorbital and preorbital regions, relative to the
braincase, are much reduced in whatever plane measured.

Differences from _richardsonii_, additional to those noted above in the
formal description of the skull, between the males, are: larger in all
parts measured except length of tympanic bulla which is about the same;
42 per cent heavier; relative to basilar length, skull broader with
preorbital part longer as well as broader; tympanic bullae more
inflated posteriorly. The same differences prevail between females
except that the skull is 36 per cent heavier and in _arctica_ the
length of the bulla is actually more (although relative to the basilar
length less) and its greater inflation posteriorly is hardly
perceptible. Differences from _alascensis_, additional to those
indicated in the formal descriptions of the skulls of the two, in
males, are: larger in every part measured; 95 per cent heavier;
relative to the basilar length, skull broader with preorbital part
longer as well as broader; measured at a point opposite the foramen
lacerum anterius, the width of the pterygoid space is more, rather than
less, than 40 per cent of its length. Excepting this difference in
width of interpterygoid space, the same differences prevail between
females, those of _arctica_ being 56 per cent heavier.

Comparison with _semplei_ is made in the account of that subspecies.

Skull indistinguishable from that of _polaris_.

_Remarks._--The person who studies specimens of this subspecies finds
labels inscribed with the names of naturalists well known to all
readers of literature on the Arctic. Sir John Franklin, R. McFarlane,
R. Kennicott, E. W. Nelson and R. M. Anderson are names which appear
commonly. Of Alaskan specimens prepared according to modern methods, a
large share was obtained by O. J. Murie and L. R. Dice.

The ermine was observed in the far north by early explorers and was
mentioned in the literature, almost always under the name then used for
the ermine of northern Europe and Asia. In 1896 Bangs misapplied to it
the name _richardsonii_ but Merriam in the same year corrected the
application of this name and proposed as new for this weasel the name
_arctica_, the name in use today. For almost 50 years after Merriam and
Bangs wrote about it, _arctica_ was treated, nominally at least, as a
species distinct from its other relatives in both the Old-and
New-World. The subspecific status of _arctica_ was emphasized in 1944
(555) by the present writer in reporting in detail upon the specimens,
of _Mustela erminea_, from Eastern Asia which were made available on
loan by Professor B. S. Vinogradov and the late Anatol I. Argyropulo of
the Leningrad Academy of Sciences. Specimens of _Mustela erminea
kaneii_ from the Asiatic side of Bering Strait and _Mustela erminea
arctica_ from the American side are distinguishable by slight cranial
characters but in coloration and external measurements I can detect no
differences. Merriam's (1896:16) mention of more golden-colored upper
parts and darker underparts in American specimens than in _erminea_ was
the result of his comparison of Alaskan and northern European
specimens. When Old World specimens from eastern Siberia, instead of
from Europe, are used the differences mentioned by Merriam do not
apply. Incidentally, many Siberian specimens have the white border, on
the ear, which Merriam (_loc. cit._) noted as a distinguishing feature
of _arctica_. When Merriam named _arctica_ he said (1896:15, 16)
"_Putorius arcticus_ . . . has heretofore been confounded with
_erminea_ or _richardsonii_. . . . It is interesting to find in this
country an Arctic circumpolar weasel which, though specifically
distinct, is strictly the American representative of the Old World
_erminea_." Bearing in mind that Merriam's concept of species and
subspecies (see Merriam, 1919:6) differed from that of nearly all
modern systematists it is clear from his statement quoted above that
he correctly understood the zoölogical relationship obtaining between
the ermines of the Old and New Worlds.

Ognev (1935:31) seems to have been the first to use the name
combination _Mustela erminea arctica_ for Alaskan specimens. Thereby he
expresses the view adopted here, namely that the American ermine is
subspecifically but not specifically distinct from the Old World
animal. Whether actual intergradation (crossbreeding) ever takes place
across the narrow Bering Strait I do not know. I doubt that
crossbreeding occurs but considering the Diomedes (islands), that might
serve as a half way stopping point, and remembering Mr. Charles
Brower's oral statement to me that he had seen tracks of ermine as far
as 10 miles from the northern shore of Alaska out on the ice, the
possibility must be granted of an occasional individual crossing from
one side to the other of Bering Strait on the ice in winter or of being
carried across when the ice broke up and drifted. If transfers of this
kind occurred often one would expect ermines to occur also on Saint
Lawrence Island where apparently they do not. The one skin (U. S. Nat.
Mus. no. 259046) seen as labeled from there, my friend, Otto William
Geist ascertained was imported as a skin with other furs from Siberia.

Ognev (_op. cit._) who used the name combination _Mustela erminea
arctica_ for Alaskan specimens, applied it also to animals from
Kamchatka. At the same time he recognized the animal from the eastern
mainland of Siberia (as opposed to the peninsula of Kamchatka) under
the name _Mustela erminea orientalis_ Ognev 1928. Hall (1944:556)
applied the earlier proposed name _Putorius kaneii_ Baird 1857, to the
animal on the eastern mainland of Asia and proposed the new name
_Mustela erminea digna_ for the ermine of Kamchatka. In comparing
material of these two Asiatic races with topotypes and other specimens
of _M. e. arctica_ from Alaska, it seemed to me that the degree of
relationship, one with the other, was about the same. _M. e. digna_ has
a slightly larger preorbital region than _M. e. kaneii_, and the skull
is longer. In both of these particulars _digna_ approaches closer to
_arctica_. _M. e. kaneii_ has longer tympanic bullae and a wider skull
than _digna_ and therein approaches more towards _arctica_ than toward
_digna_. As nearly as I can make out, _digna_ and _kaneii_ show a
nearly equal degree of resemblance to _arctica_. Also the degree of
difference between _digna_ and _kaneii_ is about the same as between
either one of them and _arctica_. In view of the above considerations
the ermines of the New and Old worlds are here regarded as only
subspecifically distinct.

In the original description of _Putorius audax_ (here regarded as
inseparable from _Putorius arcticus_ Merriam) Barrett-Hamilton
erroneously designated the type locality as "Discovery Bay, North
Greenland" whereas he should have written Grinnell Land [= Ellesmere
Island of modern terminology] in place of Greenland. As reference to
Nares (1877 and 1878) will readily reveal, Discovery Bay is near 65° W
and 81° 40´ N, across Robeson Channel, to the west, from Greenland. The
label on the type specimen and the specimen register in the British
Museum of Natural History each designates the locality for this
specimen, the type of _audax_, as Discovery Bay without mention of
Greenland. The published accounts of Feilden (1878) and Nares (1877 and
1878) state that specimens of ermine were obtained at Discovery Bay.
Probably H. C. Hart is the collector of the specimen; he was the
naturalist attached to H. M. S. Discovery which wintered at Discovery
Bay while H. W. Feilden was the naturalist attached to H. M. S. Alert
which wintered a few miles southeast of Cape Sheridan, also on the
eastern coast of Ellesmere Island.

It is true that from these ships a trip was made into Greenland and an
ermine (only one individual it seems) was obtained there, but this
individual was the type specimen of _Mustela erminea polaris_, in the
account of which race something of the history of this specimen is
given.

With the material available--and it is not entirely adequate--I can
detect no features by which animals from the type locality of _audax_
can be distinguished from typical _arctica_ which latter name has
priority.

Intergradation with _richardsonii_ probably occurs completely across
the continent. Intergrades here referred to _arctica_ include those
from Fort Goodhope. The one defective specimen from Lake Lebarge,
Yukon, is not certainly identified as _arctica_ and how far west of
Teslin Lake the boundary-line between _arctica_ and _richardsonii_
should be drawn remains to be ascertained. The one specimen available
from Hinchenbrook Island, no. 912 Mus. Vert. Zoöl., an adult female, is
doubtfully referred to _arctica_ because the damaged tympanic bullae
appear to be no larger than in _alascensis_, and the size of the skull
is more as in _alascensis_ although intermediate between that race and
_arctica_. Shape of the skull is more as in _arctica_. Possibly more
nearly adequate material would show the existence on Hinchenbrook
Island of an insular race differing in about the same degree from
_arctica_ of the mainland as does the insular _kadiacensis_.
Nevertheless, the males from farther south at Cape Yakataga are in all
respects _arctica_ and this argues against near relationship to
_alascensis_ of the animal on Hinchenbrook Island. The three animals
seen from Yakutat Bay are so young as not to display clearly the
cranial characters of the subspecies but the extension of the color of
the underparts onto the underside of the tail in them and also in the
skin without corresponding skull from Glacier Bay, Alaska, is as in
_arctica_, the race to which they are referred, and gives substantial
basis for showing the geographic range of _arctica_ as extending this
far south along the Pacific Coast.

     _Specimens examined._--Total number, 281, arranged alphabetically
     by Districts and from north to south in each District. Unless
     otherwise indicated, specimens are in the collection of the United
     States National Museum.

     =Alaska.= Point Barrow, 22 (1[1], 1[2], 1[75], 4[1], 7[60], 6[74]);
     Flaxman Island, 3; Collinson Point, 1[77]; Salirochet River,
     1[77]; Hulahula River, 1[2]; 69°20´ & 141°, 1; Rampart House, 1;
     Yukon River, mouth of Porcupine River, 18; Alatna River, 30 mi.
     from mouth, 1; Koyakuk Riv., 16 mi. below Bettles, 4; Shelton,
     1[75]; Kruzamepa, 1[75]; Tanana, 6; Boulder Creek, Chena River, 3;
     Fort Reliance, 4; Yukon River, 20 miles above Circle, 2; Mts. near
     Eagle, 42 (1[60]); Snake River, Nome, 1[9]; Nulato, 3;
     No[e]wikakat Riv., 1; Kantishna, 3; Fairbanks, 5 (1 20 mi. E and 1
     33 mi. E); Richardson, 1; N. Fk. Kuskokwim R. at base of Mt.
     Sischo, 1; N. Fk. Kuskokwim R. at Junction with McKinley Fk., 1;
     Nenana Riv., mouth of Maurice Cr., 1; Ober Cr., trib. of Jarvis
     Cr., Delta Riv. region, 1; head of Savage Riv., near Jennie Cr.,
     1; Wonder Lake, 1[74]; Bear Cr., 3; Unlakleet, 3; St. Michaels,
     11; 125 mi. E and a little N of Knik, Cook Inlet, on S side
     Matanuska Range, 1[60]; Hope, Cook Inlet, 1; Iak Lake, 1[68]; head
     of Behring Riv., 1; Bethel, 2; Kenai Lake, 8; Kenai Peninsula, 13
     (2[2]); He[i]nchenbrook Island, 1200 ft., 1[74]; Sunshine Point,
     Kaliekh River, Yakataga Dist., 1[8]; Cape Yakataga, 3[8]; Yakutat
     Bay, 3[74]; Seward, 7; Seldovia, 22 (4[2]); Homer, 1[2]; Cape
     Elizabeth, 18; Akchookuk Lake, 1; Lake Weelooluk, 1; Kokwok Riv.,
     80 mi. up, 4; Nushagak, 1; Nushagak Riv., 1; Kolukuk, 1; Egooshik
     River at mouth, 1; Glacier Bay, 1; Becharof Lake, between Portage
     Bay and Becharof Lake, 1; Ugashik Riv., 4; Chignik, 7; East base
     Frosty Peak, 1; Pavlov Bay, 1[100]; Mt. Pavlof, 1[75]; Unimak
     Island, 2 (1[75]).

     =District of Franklin.= Cape Sheridan, 1[2]; Discovery Bay,
     Ellesmere Island, 1[7] (type specimen of _Putorius audax_
     Barrett-Hamilton); Axel Heiberg Island, 1[95]; Bache Peninsula,
     Ellesmere Island, 1[77]; Bedford Pims Island, 4[75]; Craig Harbor,
     2[77]; Cape Kellett, Banks Island, 1[77]; Franklin Isthmus, 1[95];
     King William Island, 2[95].

     =District of Keewatin.= Ualiak, Ogden Bay, 2[95].

     =District of Mackenzie.= Baillie Island, 1[75]; Franklin Bay, 1;
     Langton Bay, arm of Franklin Bay, 15 mi. S of, 1[2]; Cockburn
     Point, 69°N, 115°W, 2[77]; Dolphin and Union Strait, 1[77];
     Bernard Harbor, 2[77]; Kent Peninsula, 4[95]; Horton Riv., near
     Fort Anderson, 1; Fort Anderson, 6; Anderson River, 3; Barry
     Island, Bathurst Inlet, 1[77]; Fort McPherson, 1; Peels River, 2;
     Arctic Red River, 8[75]; Fort Good Hope, 6; Clinton Colden, 1[2].

     =Yukon.= Kamarkak, 1[77]; Herschel Island, 1[75]; Lapierres House,
     2; Forty Mile, L. T. Coal Cr., 4[74]; head of Coal Cr., 1;
     Macmillan River, Forks, 1; 20 mi. W. Ft. Selkirk, 1; Slims River,
     near Kluane, 1[75]; head of Lake Lebarge, 1.


=Mustela erminea polaris= (Barrett-Hamilton)

Ermine

    _Putorius arcticus polaris_ Barrett-Hamilton, Ann. and Mag. Nat.
      Hist., 13 (ser. 7):393, May, 1904.

    _Mustela erminea_, Manniche, Meddelelser on Grønland, 45:80-85, 1
      fig., 1910.

    _Mustela arctica polaris_, Miller, U. S. Nat. Mus. Bull., 79:97,
      December 31, 1912.

    _Mustela erminea polaris_, Hall, Journ. Mamm., 26:179, July 19,
      1945.

     _Type._--Probably female, skin only; no. 78. 6. 19. 11, Brit. Mus.
     Nat. Hist.; Gap Valley, 7-1/4 miles northeast Cape Brevoort, 82°
     N, 59° 20´ W, Northwestern Greenland; June 15 or 16, 1876;
     obtained by Lewis A. Beaumont.

     The skin is in full, fresh summer pelage, fairly well stuffed
     except for the tail which is unstuffed; the whole is in a good
     state of preservation.

     _Range._--North coast, and east coast as far south as Turner Sound
     (between 69 and 70 degrees) of Greenland. See figure 25 on page
     95.

     _Characters for ready recognition._--Differs from _M. e. arctica_
     in lighter upper parts (near [_j_] Buckthorn Brown rather than Raw
     Umber or darker) and more intensely-colored underparts that are
     Buff Yellow rather than Sulphur Yellow, Colonial Buff, or Primrose
     Yellow; from _M. e. semplei_ in color in same fashion as from
     _arctica_ and in larger size of skull.

     _Description._--_Size._--Male: One subadult and two adults (one
     ad. from Scøresby Sound and other two from Ymer Island) measure as
     follows, the average being given first: Total length, 318 (301,
     320, 315); length of tail, 72 (69, 70, 73); length of hind foot,
     46.5 (44, 46, 47).

     Female: No measurements taken in the flesh available but hind
     foot, measuring 33.5 in the dried state and therefore
     approximately 35 in life.

     _Color._--As described in _Mustela erminea arctica_ except that
     upper parts in summer near (_j_) Buckthorn Brown and tone 4 of
     Dark Fawn of plate 307 to tone 1 of Raw Umber of plate 301 of
     Oberthür and Dauthenay. Underparts Buff-Yellow. Least width of
     color of underparts averaging, in 3 males, 66 (57-72) per cent of
     greatest width of color of upper parts. Black tip of tail in same
     males averaging 71 (70-72) mm. which is 99 (99-104) per cent of
     length of tail-vertebrae.

     The lighter-colored upper parts and more intensely yellow
     underparts are the distinguishing features of the subspecies
     _polaris_ in comparison with other races of American _M. erminea_.

     _Skull._--Male (based on 5 adults from eastern Greenland): See
     measurements. As described in _Mustela erminea richardsonii_
     except that: Weight more (not recorded); basilar length, 41.3
     (39.0-42.4); length of tooth-rows more than length of tympanic
     bulla; breadth of rostrum measured across lacrimal processes
     averaging more than a third of basilar length; interorbital
     breadth more than distance between glenoid fossa and posterior
     border of external auditory meatus; zygomatic breadth more than
     distance between last upper molar and jugular foramen.

     Female (based on 2 adults, Turner Sund and Kap Hoeg): See
     measurements. As described in _Mustela erminea arctica_ except
     that basilar length 36.8 (35.9, 37.8), and length of tooth-rows
     not more than length of tympanic bulla. Skulls of females not in
     hand when this comparison is written; only the recorded
     measurements are available.

To me the skull of _polaris_ is indistinguishable from that of
_arctica_. Therefore the comparisons made of the skull of _arctica_
with those of other subspecies will apply also for _polaris_.

_Remarks._--In view of the heretofore erroneous assignment of the type
locality of _Mustela erminea audax_ to Greenland, pains were taken to
verify the statement by Barrett-Hamilton (1904:393) relative to the
type specimen of _polaris_. Taking pains thus seemed the more
worthwhile because in the specimen register at the British Museum of
Natural History, there is written to the right of catalogue numbers
78-6 = 19 nos. 1-11, "Discovery Bay Presented by Mr. Hart Arctic
Collection." This refers to no. 78.6.19.1. There are no ditto marks
below but by implication this data applies also to nos. 1-11, which
include the holotype of _polaris_. A label attached to the specimen
does however give the locality as "Hall Land" "N Greenland" and another
label has on it "Ermine, procured by Mr. Beaumont Greenland Lat 89°
Long W 59-20." The 89° is obviously a mistake (on the label or in my
transcription of it) for 82°.

Reference to Nares (1877:385) reveals that Lieutenant Lewis A.
Beaumont, under date of June 15 and 16, 1876, wrote in his field
journal as follows: "I shot an ermine." In the daily accounts of his
journey from Discovery Bay on Grinnell Land [= Ellesmere Island],
across Robeson Channel and along the north coast of Greenland to the
west base of Mount Farragut near 50° 30´ W he mentions the ermine only
this once. For several other kinds of animals, Beaumont mentions
individuals seen or shot, often with the notation that this is the
second, or third seen. This mention of a kind of animal whenever seen
was in accordance with orders. On page 39 of the Discovery Report (_op.
cit._, 1877) in "General orders to sledging parties" by Captain G. S.
Nares, Commanding the Expedition, we find ". . . note daily: IV State
the animals seen and those shot." Reference to the map facing page 358
of the (_op. cit._) report reveals that on the 15th and 16th, camps
were made by Beaumont in Gap Valley, each 7-3/4 miles northeast of Cape
Brevoort, one camp on either side of the 82° line, and separated from
each other by a distance of only 2-1/4 air line miles or 4-1/2 miles
march according to his journal.

These several data, then, are the bases for designating the type
locality of _M. e. polaris_, in the way that I have stated it at the
beginning of this account of the subspecies.

The light-colored upper parts and more intensely yellow underparts well
differentiate this subspecies from _arctica_ or _semplei_.
Intergradation is suggested by a skin, no. 1462, Copenhagen Zoological
Museum, from Axel Heibergs Land, the color of the underparts of which
agrees with that of specimens from Greenland. Also the color of the
upper parts is decidedly nearer that of animals from Greenland than to
that of specimens from Ponds Inlet, Tulican and Gifford River. No other
specimens west or south of Greenland suggest intergradation. In
Greenland itself, one adult, a female from Turner Sund, East Greenland,
has the underparts no more yellowish than in some specimens from
Melville Peninsula. This female is darker on the back than any one of
the other 10 specimens from Greenland in summer pelage examined at the
same time, but even so is not so dark colored as animals from Baffin
Island or other islands to the west of Greenland.

The final summation of information about this subspecies would have
been more precise if I had been able to have actually in hand, at the
time of writing, specimens preserved in the Copenhagen Zoological
Museum. The war made it impractical to secure the loan of these as
previously planned. Even so, the measurements and notes on color that I
obtained from this material, in 1937, in Copenhagen, suffice to prove
that the subspecies _polaris_ is well set off in color from the other
American subspecies of _Mustela erminea_.

The best material of this subspecies is in the University Zoological
Museum at Copenhagen, Denmark.

     _Specimens examined._--Total number, 35, arranged by locality from
     the western end of the north coast of Greenland, eastward and then
     southward down the east coast. Unless otherwise indicated,
     specimens are in the Universitetets Zoologisk Museum, Købnhavn,
     Danmark.

     Gap Valley, 7-1/4 mi. NE Cape Brevoort, 82 N, 59 20´ W, 1 (British
     Mus.); Dragon Point, 1; Danmarks Havn (Fjeldene ved Baadskjeret,
     1; lille Fjeld, 1; Lyservig, 1; harefjeldets, 4; Rypefjeldet, 1;
     Baadskjeret, 1; Danmarkshavn, 3) 12; Christians Havn, 1 (not found
     on map); Shannon Island, 4; Germania Havn, 2; Claveringoen, 1;
     Carls Havn, 1; Myggbukta, 2 (British Mus.); Ymer[s] Island, 2
     (Mus. Comp. Zool.); Kap Hoegh, Jamesonsland, 1 (Berlin Zool.
     Mus.); Scoresby Sund, 3; Turner Sund, 4.


=Mustela erminea semplei= Sutton and Hamilton

Ermine

Plates 2, 3, 4, 9, 10 and 11

    _Mustela arctica semplei_ Sutton and Hamilton, Ann. Carnegie Mus.,
      21:79, February 13, 1932.

    _Mustela arctica labiata_ Degerbøl, Rept. 5th Thule Exped., 2 (no.
      4):25, 1935, type from Malugsitaq, Melville Peninsula, Canada.

    _Mustela erminea semplei_, Hall, Journ. Mamm., 26:179, July 19,
      1945.

     _Type._--Male, subadult, skull and skin; no. 6470, Carnegie Mus.;
     Coral Inlet, South Bay, Southampton Island, Canada; October 8,
     1929; obtained by George Miksch Sutton, original no. 3M.

     The skull has two holes in it: one is immediately above the left
     canine, and the other (2 × 5.5 mm.) is 3 millimeters to the left
     of the median line at the juncture of the frontal and parietal
     bones. From this last mentioned hole a fracture extends back
     halfway to the lambdoidal crest. The tip of the left upper canine
     is broken off. Otherwise the skull is complete, and the teeth all
     are present and entire. The skin is well made and in fresh white
     winter pelage except for a trace of the old brown summer pelage on
     the back, on the tail, on the anterior borders of the ears, and in
     a spot 11 mm. long and 8 mm. wide on the nose.

     _Range._--Baffin and Southampton islands, Melville Peninsula and
     west side of Hudsons Bay as far south as Eskimo Point. See figure
     25 on page 95.

     _Characters for ready recognition._--Differs from _M. e. arctica_,
     in that, in males, hind foot less than 44 and basilar length less
     than 41 and in that females average smaller, their skulls being
     only about 10 per cent lighter; from _M. e. polaris_ in darker
     upper parts (Raw Umber rather than Buckthorn Brown) and
     less-intensely-colored underparts that are Sulphur Yellow,
     Colonial Buff or Primrose Yellow rather than Buff Yellow, and in
     lesser size in the same fashion as from _arctica_; from _M. e.
     richardsonii_, of both sexes, in that proximal two-thirds of under
     side of tail colored same as underparts rather than same as upper
     parts and by least interorbital breadth amounting to more, instead
     of less, than distance between glenoid fossa and posterior border
     of external auditory meatus.

     _Description._--_Size._--Male: Ten adults and subadults, from
     Southampton Island, yield average and extreme measurements as
     follows: Total length, 282 (267-318); length of tail, 77 (59-87);
     length of hind foot, 40 (38-43).

     Female: Four subadults from Southampton Island yield average and
     extreme measurements as follows: Total length, 271 (256-288);
     length of tail, 71 (69-74); length of hind foot, 35 (33-38).

     _Color._--As described in _M. e. arctica_ except that least width
     of color of underparts averaging, in 7 males, 59 (45-81) per cent
     of greatest width of color of upper parts. Black tip of tail in 19
     male topotypes averaging 72 (64-83) mm. which is 91 (75-122) per
     cent of length of tail-vertebrae.

     _Skull._--Male (based on 2 adults and 10 subadults from
     Southampton Island): See measurements and plates 2-4. As described
     in _Mustela erminea richardsonii_ except that: Weight, 2.0 (in one
     subadult) grams; basilar length, 37.5 (35.7-39.9); length of
     tooth-rows more than length of tympanic bulla; breadth of rostrum
     more than a third of basilar length; interorbital breadth more
     than distance between glenoid fossa and posterior border of
     external auditory meatus; zygomatic breadth more than distance
     between last upper molar and jugular foramen.

     Female (based on 1 adult and 4 subadults from Southampton Island):
     See measurements and plates 9-11. As described in _Mustela erminea
     richardsonii_ except that: Weight, 1.35 (in one adult) grams;
     basilar length, 34.2; breadth of rostrum more than 30 per cent of
     basilar length; interorbital breadth more than distance between
     glenoid fossa and posterior border of external auditory meatus;
     zygomatic breadth more or less than (approximately same as)
     distance between last upper molar and jugular foramen.

In comparison with _richardsonii_, the skulls of males averaged smaller
in every measurement taken except breadth of rostrum and interorbital
breadth which are more, and zygomatic breadth and length of inner lobe
of M1 which are approximately the same; skull about 20 per cent
lighter; in relation to basilar length, preorbital region longer and
broader in every part measured. Female averages larger, in every part
measured; 23 per cent heavier; in relation to basilar length, every
other measurement more. It is noteworthy that the skull of the male is
smaller and the skull of the female larger than in _richardsonii_.

Differences from _arctica_ are: Size less, in each sex; males about 40
per cent and females 10 per cent lighter; in males, skull more rounded
in outline as viewed from above because zygomatic arches arise less
abruptly from skull; in males tympanic bullae do not project so far
ventrally from squamosal floor of braincase; with these exceptions,
skull of _semplei_ can be said to be a smaller edition of that of
_arctica_.

From _polaris_, _semplei_ differs, cranially, in the same way as from
_arctica_.

_Remarks._--There is a slight increase in size of ermines toward the
north which probably is the result of intergradation between _semplei_
and _arctica_. Specimens from the northern part of Baffin Island are
larger than those from farther south. Specimens from the mainland west
of Southampton Island may owe their smaller (than in _arctica_) size to
intergradation with _richardsonii_ almost as much as to intergradation
with _semplei_.

Degerbøl's name _Mustela arctica labiata_ was applied to specimens,
which to me are indistinguishable from topotypes of _Mustela arctica
semplei_, which latter name has three years priority. Degerbøl
(1935:34) states that Malugsitaq, Melville Peninsula, is the type
locality. He did not designate a type specimen. Reference to his
account (_op. cit._:26) shows that he lists five specimens from the
type locality, or more precisely as "Malugsitaq, Lyon Inlet. 5 summer
skins. [M] [M] June-July 1922. P. F., CN. 2262-2266." On labels
attached to these specimens, "Lyon Inlet" is replaced with "Melville
Peninsula." On July 28, 1937, Degerbøl and I together examined these
specimens in his laboratory. Because no. 2262 is first mentioned I
regard it as the type. It is a juvenal male, skull and skin, no. 2262
(20.5 1931.8), Univ. Zool. Mus. Copenhagen, obtained in June or July of
1922 by Peter Freuchen whose original number was / s 2324. The specimen
is one of 5 males taken at the same locality by the same collector and
they bear identical data as to date. They look to be of the same
litter for all are roughly of the same size and each retains milk
teeth.

Additional females, with external measurements carefully taken, are
much needed from Southampton Island, because the available females are
insufficient to show the degree of sexual dimorphism. If the meager
data available be accepted, the difference in size between the two
sexes is less than in other subspecies. My own feeling is that a better
sample of females would show the secondary sexual difference in size to
be more than available data indicate.

     _Specimens examined._--Total number, 183, arranged from north to
     south by islands, or regions attached to the mainland, and from
     north to south in each region or island. Unless otherwise
     indicated, specimens are in the Zoological Museum, University of
     Copenhagen, Denmark.

     =Baffin Island.= Pond[s] Inlet, 8; (5[77]); Tulukan (sometimes
     spelled Tulukat), 6; Cape Eglinton, 1[7]; Gifford River, 2; Clyde,
     3[86]; head of Cumberland Sound, 1[91]; Pangnirtung, 2[77];
     Kingnait Fiord, 1[91]; Kikkulin Island, Cumberland Sound, 1[7];
     Blacklead Island, Cumberland Gulf, 1; merely Cumberland Gulf,
     1[7]; merely east Baffin Island, 34[7]; Cape Dorset, 2[2]; SW
     coast of Baffin Island, 1[75].

     =Melville Peninsula.= Iglulik, 3; Pingerqalik, 2; Kingadjuaq,
     Amitsog, 3; Rae Isthmus, 3; Lyons Inlet, 13(9[2]); M[N?]
     alugsitaq, Lyon Inlet, 5; Itibdjeriang, 2; Repulse Bay, 27 (22[2],
     2[19]); Drichetts Cove, Hurd Channel, 1[2]; Gore Bay, 1; Haviland
     Bay, 1; Cleveland Harbor, Frozen Strait, 1.

     =Southampton Island and adjacent islands.= Danish Island, 11;
     Vansittart Island, 4. Southampton Island: Coral Inlet, 19 (1[77],
     18[9]); Prairie Point, 1[9]; Munnimunnek Point, South Bay, 5[9];
     Native Point, 1[9]; Ranger Rim, 1[9]; Koodloatok (not found on
     map), 1[77]; merely Southampton Island, 1[77]; Gore Bay, 1[2]; Fox
     Channel, 2[2].

     =Mainland to west of Southampton Island.= Cape Fullerton, 3
     (1[77], 2[2]); Chesterfield Inlet, 4 (1[77], 1[9]); Tavane, 1[77];
     N of Wagner Inlet, 1; Eskimo Point, 1[86].


=Mustela erminea kadiacensis= (Merriam)

Ermine

Plates 2, 3, 4, 9, 10 and 11

    [_Putorius arcticus_] subspecies _kadiacensis_ Merriam, N. Amer.
      Fauna, 11:16, June 30, 1896.

    _Putorius kadiacensis_, Preble, Proc. Biol. Soc. Washington,
      12:169, August 10, 1898.

    _Mustela kadiacensis_, Miller, U. S. Nat. Mus. Bull., 79:97,
      December 31, 1912.

    _Mustela erminea kadiacensis_, Hall, Journ. Mamm., 26:179, July 19,
      1945.

     _Type._--Male, subadult, skull and skin; no. 65290, U. S. Nat.
     Mus., Biol. Surv. Coll.; Kodiak Island, Alaska; April 25, 1894;
     obtained by B. J. Bretherton, original no. 304.

     The skull lacks the basioccipital, part of the basiphenoid, the
     occipital region on the right side and the posterior part of the
     right tympanic bulla. The third, upper, left incisor is missing.
     Otherwise the teeth all are present and entire.

     The white, winter skin is only moderately well stuffed but in a
     good state of preservation. The spring coat is appearing along the
     back. This coat is visible at only two places unless the hair be
     parted when the new brown pelage, which is coming in, can be seen
     all along the midline of the back.

     _Range._--Kodiak Island, Alaska. See figure 25 on page 95.

     _Characters for ready recognition._--Differs from _M. e. arctica_
     in hind foot less than 33 in females and in zygomatic breadth
     amounting to less, instead of more, than distance between last
     upper molar and jugular foramen irrespective of sex.

     _Description._--_Size._--Male: One adult and 3 subadults yield
     average and extreme measurements as follows: Total length, 341
     (318-360); length of tail, 93 (86-102); length of hind foot, 47
     (44-49).

     Female: An adult measures: Total length, 258; length of tail, 70;
     length of hind foot, 31.

     _Color._--As described in _M. e. arctica_, except that least width
     of color of underparts averaging 54 (40-83) per cent of greatest
     width of color of upper parts. Black tip of tail in 3 males in
     summer pelage averaging 80 (70-90) mm. which is 85 (69-96) per
     cent of length of tail-vertebrae.

     _Skull._--Male (based on 2 adults): See measurements and plates
     2-4. As described in _Mustela erminea richardsonii_ except that:
     Weight 3.1 grams; basilar length, 42.6 (42.1-43.2); length of
     tooth-rows more than length of tympanic bulla; breadth of rostrum
     measured across lacrimal processes averaging more than a third of
     basilar length; interorbital breadth more than distance between
     glenoid fossa and posterior border of external auditory meatus.

     Female (based on one adult, no. 98042): See measurements and
     plates 9-11. As described in _Mustela erminea richardsonii_ except
     that: Weight, 1.2 grams; basilar length, 33.0; length of
     tooth-rows more than length of tympanic bulla.

Comparison with _arctica_ has been made in the account of that
subspecies. Although _richardsonii_ and _kadiacensis_ are described as
having the zygomatic breadth less than the distance between the last
upper molar and jugular foramen, the zygomatic breadth is considerably
more in _kadiacensis_ than in _richardsonii_; consequently the two
dimensions are more nearly equal than in _richardsonii_. Except for
being slightly narrower, the skull of _kadiacensis_ is only a slightly
smaller edition of that of _arctica_.

_Remarks._--When naming the weasel from the mainland of Alaska as new,
under the name _Putorius arcticus_, Merriam (1896:16) wrote: "A small
form of _arcticus_ occurs on Kadiak Island. . . . It is probably worthy
of recognition as subspecies _kadiacensis_." The informality of this
description possibly was in part due to the describer's recognition of
the fact that the degree of difference between _arcticus_ and the
insular _kadiacensis_ was slight. Specimens collected after Merriam
proposed the name for the weasel of Kodiak Island show the animal there
to be less different from _arctica_ of the adjacent mainland than he
thought; small size is the most pronounced distinction of
_kadiacensis_ and Merriam's male type specimen is smaller than any of
the five additional males saved from Kodiak Island since that time.
Even so the differences fully warrant subspecific recognition, in my
opinion, although _kadiacensis_ is not a strongly differentiated race.
More adult females are needed to ascertain the norm of form and size
for that sex. If the one female known is typical, the difference from
_arctica_ is more pronounced in females than in males. The lesser size
of _kadiacensis_ can hardly be credited entirely to the effect of
insularity, for animals from the southern part of the mainland, on
Kenai Peninsula for example, are smaller than those from central and
northern Alaska and provide evidence of intergradation of a sort
between _kadiacensis_ and _arctica_.

     _Specimens examined._--Total number, 9, all from Kodiak Island,
     Alaska, and unless otherwise indicated in the U. S. National
     Museum.

     Karluk, 1 (Stanford Univ.); Kodiak, 7; Kodiak Island, 1 (Field
     Mus. Nat. Hist.).


=Mustela erminea richardsonii= Bonaparte

Ermine

Plates 2, 3, 4, 9, 10 and 11

    _Mustela richardsonii_ Bonaparte, Charlesworth's Mag. Nat. Hist.,
      2:38, 1838.

    _Putorius cicognanii_, Baird, Mamm. N. Amer., p. 161, 1858 (part).

    _Putorius richardsonii_, Baird, Mamm. N. Amer., p. 164, 1858
      (part-Halifax, N. S.).

    _Putorius_ (_Gale_) _erminea_, Coues, Fur-bearing animals, p. 109,
      1877 (part).

    _Putorius richardsoni_, Bangs, Proc. Biol. Soc. Washington, 10:16,
      February 25, 1896.

    _Putorius cicognani richardsoni_, Merriam, N. Amer. Fauna, 11:11,
      June 30, 1896.

    _Putorius (Arctogale) cicognanii cicognanii_, Bangs, Proc. New
      England Zoöl. Club, 1:18, February 28, 1899.

    _Putorius microtis_ Allen, Bull. Amer. Mus. Nat. Hist., 19:563,
      October 10, 1903. Type from Shesley, British Columbia.

    _Putorius arcticus imperii_ Barrett-Hamilton, Ann. and Mag. Nat.
      Hist., 13(ser. 7):392, May, 1904. Type from Fort Simpson,
      Mackenzie, Canada.

    _Putorius cicognanii richardsoni_, Preble, N. Amer. Fauna, 27:231,
      October 26, 1908.

    _Mustela microtis_, Miller, U. S. Nat. Mus. Bull., 79:96, December
      31, 1912.

    _Mustela cicognanii mortigena_ Bangs, Bull. Mus. Comp. Zoöl.,
      54:511, July, 1913. Type from Bay St. George, Newfoundland.

    _Mustela cicognanii_, Sheldon, Journ. Mamm., 13:201, August 9,
      1932.

    _Mustela cicognanii richardsonii_, Miller, U. S. Nat. Mus. Bull.,
      79:95, December 31, 1912; Hall, Univ. California Publ. Zoöl.,
      40:368, November 5, 1934.

    _Mustela cicognanii cicognanii_, Hall, Canadian Field-Nat., 52:108,
      October, 1938.

    _Mustela erminea richardsonii_, Hall, Journ. Mamm., 26:77, February
      27, 1945; Hall, Journ. Mamm., 26:180, July 19, 1945.

     _Type._--Male, age unknown, skin; no. 43.3.3.4, British Museum of
     Natural History; probably from Fort Franklin, Canada; presented to
     British Museum on or before March 3, 1843; may be the type.

     In September, 1937, when I searched in the British Museum for the
     skull, I found no trace of it nor mention of it in catalogues. The
     skin is in white, winter pelage, mounted on a pedestal. See under
     remarks for _Mustela e. cicognanii_ for reasons for and reasons
     against regarding this specimen as the holotype.

     _Range._--Hudsonian and Canadian life-zones of the greater part of
     Canada from the Atlantic to the Pacific. See figure 25 on page 95.

     _Characters for ready recognition._--Differs from _M. e. arctica_,
     _polaris_, _semplei_ and _haidarum_, in both sexes, by proximal
     two-thirds of under side of tail colored same as upper parts
     rather than same as underparts, and interorbital breadth less,
     rather than not less, than distance between glenoid fossa and
     posterior border of external auditory meatus; from _M. e. bangsi_,
     in that, in both sexes, least width of color of underparts
     averages two-fifths rather than about a third of greatest width of
     color of upper parts, and in that skulls of males are a fourth
     heavier, basilar length averaging more than 40; from _M. e.
     cicognanii_, in both sexes, in that least width of color of
     underparts averages two-fifths instead of less than a third of
     greatest width of color of upper parts, in females by 20 per cent
     heavier skull (1.1 versus 0.92), in males by skull more, rather
     than less, than 1.9 grams, and basilar length more, instead of
     less, than 38; from _M. e. invicta_, in males, by skull more,
     instead of less, than 1.9 grams; mastoid breadth more, instead of
     less, than 19.9 mm.; depth of skull at anterior margin of
     braincase more, instead of less, than 12.4 mm.; in females, by
     same measurement of depth more, instead of less, than 10.1, and
     weight of skull averaging more, instead of less, than one gram;
     from _M. e. fallenda_ in both sexes upper lips white rather than
     brown, in males, hind foot more than 41, basilar length more than
     38.3, in females hind foot more than 29, basilar length more than
     31.4, and breadth of rostrum amounting to less, instead of more,
     than 30 per cent of basilar length; from _M. e. alascensis_ in
     males in that black tip of tail more than 43, total length more
     than 320, tympanic bullae more than 14 and longer than tooth-row
     rather than less than 14 mm. and sometimes shorter than tooth-row,
     females not individually distinguishable.

     _Description._--_Size._--Male: Four adults (Fort Franklin, Fort
     Simpson, Mts. W Fort Nelson, and Govt. Hay Camp, Wood Buffalo
     Park) yield average and respective measurements as follows: Total
     length, 331 average (340, 325, 330, 328); length of tail, 93 (102,
     91, 93, 87); length of hind foot, 45 (48, 43, 45, 44). Weight of 4
     adults from the Belcher Islands is 175 (135-180) grams. Of 10
     subadults from Belcher Islands it is 119 (92-137) grams.

     Female: Three adults from Great Slave Lake (Willow River,
     Fairchild Point, and Fort Resolution) yield average and respective
     measurements as follows: Total length, 252 (237, 238, 282); length
     of tail, 69 (63, 60, 85); length of hind foot, 32 (31, 32, 34).
     Corresponding, average measurements for three adults from Glacier
     Lake are 240, 60, 32 and for 3 adults from the Athabasca Delta,
     243, 65, 30. Weight of 8 subadults from the Belcher Islands is 69
     (64-78) grams. Weight of adults would be more.

     _Color._--Winter pelage all white except tip of tail. Summer
     pelage with upper parts uniform in color and darker (16_n_) than
     Raw Umber, and about tones 3 to 4 of Chocolate of Oberthür and
     Dauthenay, pl. 343. Underparts Sulphur Yellow, Colonial Buff, or
     Primrose Yellow, often nearly white on chin and insides of
     forelegs; color of underparts extends narrowly over upper lips,
     distally on posterior sides of forelegs onto antipalmar faces of
     toes and sometimes over most of antipalmar surfaces of forefeet,
     on medial sides of hind legs to a point between knee and ankle but
     reappears on antiplantar faces of toes and in some individuals is
     narrowly continuous onto toes. Least width of color of underparts
     averaging, in a series of 12 males from the Athabasca Lake Region,
     40 (25-54) per cent of greatest width of color of upper parts.
     Black tip of tail averaging 56 (45-63) mm. in 5 adult males from
     same region and thus 60 (48-70) per cent of length of
     tail-vertebrae.

     From _arctica_, _polaris_, _semplei_ and _kadiacensis_,
     _richardsonii_ differs in: Color darker; ventral side of tail same
     color as upper parts; light-colored underparts a fifth narrower;
     black tip of tail by actual measurement a fifth shorter and
     averaging less than two-thirds rather than more than four-fifths
     of length of tail-vertebrae. From _cicognanii_, _richardsonii_
     differs in that the underparts are a fourth wider and in some
     specimens more brightly colored. The width of the underparts is
     likewise a fourth more than in _bangsi_. In _invicta_ the
     underparts are not so brightly colored as in some specimens of
     _richardsonii_. From _fallenda_, _richardsonii_ differs in that
     the upper parts often are lighter colored, upper lips white rather
     than colored like upper parts, and underparts as wide again. In
     comparison with _alascensis_, the black tip of the tail averages
     three-fifths rather than a half of length of tail-vertebrae.

     _Skull._--Male (based on 6 adults from 3 miles south of Big
     Island, Great Slave Lake): See measurements and plates 2-4;
     weight, 2.5 (2.1-2.9) grams; basilar length, 40.9 (39.6-43.7);
     length of tooth-rows less than length of tympanic bulla; breadth
     of rostrum measured across lacrimal processes less than a third of
     basilar length; interorbital breadth less than distance between
     glenoid fossa and posterior border of external auditory meatus;
     zygomatic breadth less than distance between last upper molar and
     jugular foramen.

     Female (based on 4 adults: from Willow River, 1; Fort Resolution,
     1; Athabasca Delta, 2; and 2 subadults, one from 3 mi. S Big
     Island and one from 15 mi. above Smith Landing): See measurements
     and plates 9-11; weight, 1.1 (0.9-1.4) grams; basilar length, 33.1
     (31.5-34.2); length of tooth-rows less than length of tympanic
     bulla; breadth of rostrum less than 30 per cent of basilar length;
     interorbital breadth less than distance between glenoid fossa and
     posterior border of external auditory meatus; zygomatic breadth
     less than distance between last upper molar and jugular foramen.

     The skull of the female averages 56 per cent lighter than that of
     the male.

Comparison of the skull with that of _arctica_, _polaris_, _semplei_,
_kadiacensis_, _haidarum_, _cicognanii_, _bangsi_, _invicta_,
_fallenda_, and _alascensis_ is made in the accounts of those
subspecies.

_Remarks._--_M. e. richardsonii_ has the most extensive geographic
range of any American race of _erminea_, is centrally located with
respect to the other races, is more abundantly represented by study
specimens in zoölogical collections than any other race, and is a sort
of average for the species as a whole in most structural features.
Therefore _richardsonii_ is used as a standard of comparison and
accordingly is more fully described than any one of the other races
each of which by reference to _richardsonii_ is described in
comparative fashion. This comparative description has the virtue of
more clearly indicating differences between subspecies and also makes
for brevity.

John Richardson, Bernard R. Ross, and names of their companions, as
written on the labels of the older specimens recall to the student's
mind early explorations of the north country. Edward A. Preble obtained
important specimens at several places and in recent years J. Kenneth
Doutt and G. G. Goodwin have made the reviser's work easier by
preparing specimens in series from areas not previously well
represented.

The nomenclatural history of this subspecies begins with references in
the literature that identify the animal as the Old World species,
_Mustela erminea_--an identification which the study here reported upon
shows to have been correct in the specific, although not in the
subspecific, sense. Richardson, for example, in his "Fauna
Boreali-Americana" published in 1829 so identified the animal. In 1838,
Bonaparte, basing his description on Richardson's account of 1829,
proposed the new name _richardsonii_. Richardson himself, the following
year in the "Zoology of Beechey's Voyage," accepted Bonaparte's name
and it has been applied to the animal in the central part of the
northern timber-belt of North America ever since, except as authors
used the name _Mustela erminea_ in the belief that _richardsonii_ was
not distinct from _erminea_.

The north and south boundaries of the range assigned to _richardsonii_
varied according to the notions of the particular writer who was
employing the name. Until Merriam in 1896 named _arctica_ as distinct,
animals from the far north were generally included under the name
_richardsonii_ along with populations to which the latter name now is
applied. Because _richardsonii_ grades gradually into the smaller
_cicognanii_ of more southern occurrence the boundary between the two
has been set farther north by one writer and farther south by another,
depending probably upon what the writer felt was the halfway point in
size. This point of course depended upon the samples selected as
typical of _richardsonii_ on the north and _cicognanii_ on the south.
Because Bangs, in 1896, took as representative of _richardsonii_ the
far northern and hence large-sized animals (now separated as _M. e.
arctica_), his halfway point in size between them and the small
_cicognanii_ of New England naturally fell farther north than it would
have had he used as representative of _richardsonii_ specimens from
places south of the range of _arctica_.

In 1903 J. A. Allen proposed the name _Putorius microtis_ for a
specimen from Shesley, northwestern British Columbia, a place
approximately 50 miles northwest of Telegraph Creek. Considering the
great disparity in size between this one specimen and the other larger
specimens of normal size, from the general region, available to Allen
at that time, it is not surprising that he thought two full species
were represented. In 1943 when G. G. Goodwin called to my attention two
males, as small as the type of _microtis_ and taken by him
approximately 300 miles east of Shesley, in the valley between the
Musqwa and Prophet rivers, I for a second time examined all available
specimens and data with the possibility in mind that _microtis_ was a
species or subspecies distinct from _M. e. richardsonii_, but again
concluded that only one subspecies was involved because no character
except size was found to distinguish the large from the small
individuals of a given sex and there are, preserved from northern
British Columbia, individuals of intermediate size. _Putorius microtis_
Allen seems to have been based on an individual of _M. e. richardsonii_
near the lower limit of size for that subspecies and _microtis_ is
regarded as a synonym.

Barrett-Hamilton in 1904 named the animal at "Fort Simpson, British
Columbia" _Putorius arcticus imperii_. Preble (1908:232) pointed out
that Fort Simpson on the Mackenzie undoubtedly was the place intended,
and arranged _imperii_ as a synonym of _M. e. richardsonii_. The type
specimen of _imperii_ was stated to have been received from B. M. Ross
who is known to have collected specimens, including specimens of this
species (now in U. S. Nat. Mus.), at Fort Simpson on the Mackenzie. I
know of no Fort Simpson in British Columbia. If, as seems improbable,
Port Simpson, British Columbia, was the place that Barrett-Hamilton
intended to designate (where so far as I know Ross did not collect),
the name _imperii_ still would seem to be a synonym of _richardsonii_
because _richardsonii_ seems to be the race of weasel at Port Simpson.
In proposing the name _Putorius arcticus imperii_, Barrett-Hamilton
stressed that the weasel, which he was naming, was a subspecies of _P.
arcticus_, gave characters which applied perfectly to _richardsonii_
but made no reference to _richardsonii_. Barrett-Hamilton did not refer
to _richardsonii_ possibly because he relied on Merriam's
classification of 1896 wherein _richardsonii_ is treated as a species
distinct from _arctica_. Merriam, it will be remembered, held that
slight degree of morphological difference rather than intergradation
was the criterion for subspecies. Although I have no record of having
examined the type specimen of _imperii_ I have but little hesitancy in
treating it as a synonym, and would have no hesitancy at all in so
doing if the type was certainly known to have been obtained at Fort
Simpson on the Mackenzie.

The name _Mustela cicognanii mortigena_ Bangs, 1913, proposed for the
ermine of Newfoundland, is placed as a synonym of _richardsonii_ only
after repeated, detailed comparisons. In advance of study I supposed
that the isolation of the ermine, in Newfoundland, had contributed to
its differentiation, which, however, the original describer, Bangs,
indicated was slight. Bangs was a careful worker and I am confident
that the differences he described really existed between his specimens.
Material more nearly adequate than he had from the mainland, shows the
males, so far as my measurements and comparisons go, to be in nowise
different from those in Newfoundland. Females in Newfoundland may have,
on the average, slightly longer hind feet than on the opposite mainland
but I am not certain that they do and even if there is a slight
difference in this regard as suggested by available data, I think it
insufficient basis, alone, for according subspecific status to the
insular animal.

The name _richardsonii_ was based by Bonaparte on Richardson's
description which in turn was drawn from a specimen taken at Fort
Franklin, that thus becomes the type locality. It is fortunate that
Preble, in 1903, succeeded in taking specimens there because the place
is near the belt of intergradation between _arctica_ and
_richardsonii_. Of Preble's two adult males (see Preble, 1908:232) I
have examined no. 133847, which is in transitional pelage and therefore
gives no clue in so far as coloration is concerned, as to affinities
with _arctica_ versus _richardsonii_. Specimens in the summer pelage
are much to be desired from Fort Franklin. Regardless of what their
coloration may be, specimen no. 133847, in external measurements and
most certainly in cranial features is of the race to the south and not
the race that Merriam named _arctica_. Because all specimens from
localities to the south of Fort Franklin likewise differ from _arctica_
of the barren grounds, considerable additional confidence is felt in
allocating the name _richardsonii_ to the animal which ranges from Fort
Franklin southward rather than to the one, here designated _arctica_,
that occurs to the northward of Fort Franklin.

Although in most structural features _richardsonii_ is a sort of
average for the American races of the species, it is the extreme in
high degree of sexual dimorphism. The difference in size between the
males and females is greater than in any other race except possibly _M.
e. kadiacensis_ in which so little is known of the female that the
difference between the two sexes cannot be accurately judged. It will
aid in understanding the high degree of secondary sexual difference in
_richardsonii_ to visualize two kinds of weasels distributed over the
northern half of the continent, thinking now of the geographic area in
America occupied by the whole species _Mustela erminea_ of which the
subspecies _richardsonii_ is only a part. One of the two kinds of
weasel is the male ermine and the other the female. The decrease in
size of the male, as measured by the weight of the skull, is in the
ratio of 7 in the north to 2 in the south. This decrease is gradual
whereas the corresponding decrease from 3 to 1 in the female is not
gradual; half of the decrease in the female occurs in the short north
to south distance comprised in the belt of intergradation, along the
northern boundary of _richardsonii_, between it and _arctica_. As a
result _richardsonii_ is composed of females with medium sized skulls
and males with relatively large skulls, the ratio by weight being
approximately 5 to 2. The disproportion in races of ermines both to the
north and to the south is less. Actually in the north (_arctica_) the
approximate ratio by weight is 2-1/3:1; in _richardsonii_, 2-1/2:1; in
the south (_muricus_), 1-2/5:1. Indicated in still another way in
_richardsonii_ the skull of the female is 56 per cent lighter than that
of the male and the skull of the male is 127 per cent heavier than that
of the female. Intergradation with races whose ranges border on that of
_richardsonii_ is complete. On the northern boundary of the range of
_richardsonii_ along the western shore of Hudsons Bay for perhaps a
hundred miles north of Eskimo Point, there are intergrades with
_arctica_. As judged by their lesser size, individuals of this
population are influenced by the _semplei_-stock. Otherwise,
intergradation on the northern boundary, with _arctica_, is abrupt
whereas intergradation at the south, between _richardsonii_ and
_cicognanii_, is gradual. Intergradation is similarly gradual between
_richardsonii_ on the one hand and _bangsi_ and _invicta_ on the other.
By speaking of the intergradation as abrupt, it is intended, in this
instance, to indicate that in a relatively narrow belt, between the
geographic ranges of _arctica_ and _richardsonii_, ermines intermediate
in color-pattern, shape of skull, and size, bridge the gap between the
ermine of the tundra (_arctica_) and that in the forest belt
(_richardsonii_). It may be added that the degree of difference between
the two subspecies just mentioned is approximately twice as much as
between _richardsonii_ and _cicognanii_. The intergradation between
_cicognanii_ and _richardsonii_ is gradual. By gradual it is meant that
the change from one kind to the other is achieved in a wider area where
ermines from locality A do not differ appreciably from those taken at,
say, locality B, 50 miles farther south, although ermines from A and
those from a third locality, C, say, 130 miles south, clearly show
differences indicative of geographic variation.

     _Specimens examined._--Total number, 1035, as follows. Arranged
     alphabetically by provinces and districts and from north to south
     in each province or district. Unless otherwise indicated,
     specimens are in the United States National Museum.

     =Alberta.= 15 mi. above Smith Landing, 2; Fort Smith, 2 (1[77]);
     Smith Landing, 2; LaButte, Fitzgerald, 1[77]; Egg Lake, 15 mi. NW
     Ft. Chippewyan, 4 (2[75]); Lobstick Island, near Ft. Chippewyan,
     1; Athabasca Delta, 9 mi. above mouth of main branch, 1; Athabasca
     Delta, Long Creek, 1 mi. W of main branch, 2; Ft. Chippewyan, 1;
     Peace Point, 1[75]; 18 mi. below Peace Point, 1; Embarass River, 7
     (4[75]); Athabasca River, 1[2]; Ft. McMurray, 1; Athabasca River,
     Middle Rapid, 2; 60 mi. above Grand Rapids, 1; Boiler Rapid, 1;
     Entrance, 3[2]; St. Albert, 2.

     =British Columbia.= Fort Halket, 1; Shesley, 1[2]; Dorothy Lake,
     Mts. W of Ft. Nelson, 4000 ft., 3[2]; valley between Musqwa and
     Prophet rivers, 3800 ft., SW of Ft. Nelson, 2[2]; Sikanni Chief
     Riv., 1; Telegraph Creek, 7 (6[2]); head of Bad River, 2350 ft.,
     on lake, 1; Six Mile, 5[74]; Tuchodi Lake, 2[2]; Iskoot River,
     2[14]; Level Mtn., 1[2]; head of Tatletuey Lake, 12 mi. W Thudade
     Lake, 2; Robb Lake District, 5[2]; Ft. Grahame, 12 (2[77]); Sustut
     Mts., on trib. Sustu Riv., 25 mi. SE Thudade Lake, 2; Laurier
     Pass, 1; Omineca Mts., 1[85]; Point Creek and Clearwater River, 2;
     Kispiox Valley, 23 mi. N Hazelton, 5[74]; Hazelton, 3[77]; NW arm
     Tacla Lake, 7; N end Babine Lake, 1; Pt. Simpson, 1; Metlakatla,
     1; Stuart Lake, 27; S Fk. Salmon Riv., 1[77]; mouth Salmon Riv.,
     1[77]; Vanderhoof, 4[77]; Wistaria P. O., near Burns Lake, 1[77];
     Kruger Lake, 9[74]; Indianpoint Lake, 23[74]; Quesnel, 1; Ahbau
     Lake, 3[74]; Isaacs Lake, 6[74]; Beaver Pass, 56[74]; Lightning
     Creek, 54[74]; LaFontaine, 16[74]; Barkerville, 1[74]; Barkerville
     District, 34[74]; Swift River, 27[74]; Cunningham Creek, 34[74];
     Itcha Mts., 1[31]; Anahim Lake, 1[74]; Chezacut Lake, 8[31];
     Kleena Kleene, 18[74]; 158 mi. House (Cariboo on labels), 3[60];
     Rivers Inlet, 6 (5[94]; 1[77]); Horse Lake, 4[22]; Kingcome Inlet,
     8[77]; Loughborough Inlet, 7[77]; McGillivary Creek, 1; Camel
     Back, Pemberton Meadows, 1[31]; Arrow Rapids, mainland opposite
     Stuart Island, 1[77]; Butte Inlet, 9[77]; Green Lake, 1[31]; Mt.
     Whistler, 1[86]; Alta Lake, 2 (1[31]; 1[21]); Mons, 1[31].

     =Keewatin.= Foot of Baker Lake, 1.

     =Labrador.= Okak, 3[75]; Nain, 22 (11[75]; 11[60]); Hopedale,
     24[75]; Kippokak Bay, 7[75]; Ailik, 1; Makkovik, 26[75]; Labrador,
     55° N, 3; Hamilton Inlet, 2[75]; NW River Post, interior Labrador,
     5[1]; Cartwright, 5; Paradise, 12; Sandwich Bay (Muddy Bay, 6;
     North River, 6), 12; Battle Harbor, 1[7]; St. Marys River, 3[7];
     Black Bay, 16 (15[75]; 1[76]); Lanceau Loup, 17 (1[75]).

     =Mackenzie.= Ft. Franklin, 1[2]; Ft. Rae, 12; Fairchild Point,
     6[9]; Fort Simpson, 10 (2[2]); Hot Springs (61°, 125°), 1[2];
     Willow River, near Ft. Providence, 1; 35 mi. N Big Island, 7; Big
     Island, 9; 3 mi. S Big Island, 7; Ft. Resolution, 9; 100 mi. N Ft.
     Smith, 2; 75 mi. NW Ft. Smith, 1; Ft. Liard, 2; Sucker Creek,
     4[77]; Govt. Hay Camp, Wood Buffalo Park, 2[77].

     =Manitoba.= Egg Is., Rabbit Point, 1; Ft. Churchill, 1; Ft. York,
     W Hudsons Bay 57° N, 1[7]; Oxford House, 11; Gypsumville, 1[86];
     Lake St. Martin.

     =New Brunswick.= _Restigouche County_: Bird Bait, north Camp, 6
     mi. NE Nictau Lake, 2[59]; Red Brook, Tobique River, 1[59].
     _Victoria County_: Trousers Lake, 3[2]. _Glouchester County_:
     Youghall, 1[77]; Miramichi Road, 15 mi. from Bathurst, 13[77].
     _York County_: Scotch Lake, 2.

     =Newfoundland.= Nicholsville, 3[75]; Bay St. George, 48 (26[75];
     2[7]; 1[9]); Codroy, 9 (7[75]; 2[60]).

     =Nova Scotia.= _Victoria County_: Cape North, 2[77]. _Inverness
     County_: Fizzleton, 3[77]. _Richmond County_: St. Peters, 1[77].
     _Pictou County_: Glengary, 1[4]. _Guysborough County_: East Roman
     Valley, 5[77]. _Kings County_: Wolfville, 5 (3[74], 2[77]); near
     Wolfville, 1[77]. _Halifax County_: Hammond Plains, 1. _Annapolis
     County_: Annapolis Royal, 1. _Digby County_: Digby, 3. No locality
     more definite than Nova Scotia, 3.

     =Ontario.= Severn River, 1[77]; R. C. Mission, Yellow Creek, near
     mouth of Albany, 2[86]; Ft. Albany, 4; Charlton Island, 1; Moose
     Factory, 10 (7[9]; 3[77]); Abitibi, 1[4].

     =Quebec.= Fort Chimo, 10[77]; Ungava Forks, 1; Belcher Islands,
     Hudsons Bay (Tukarak Island, 29; Eskimo Harbor, 2; Innetalling
     Island, 1; S tip Gibson Peninsula, 2; Flaherty Island, 1), 35[9];
     Cairn Island, Richmond Gulf, 2[9]; Manitounuk Sound, 4[9]; about
     15 mi. S Great Whale River, 1[9]; Ft. George, 1[9]; Charlton
     Island, 1[9]; Waswonaby Post, 1[77]; Mistassinnay Post, 3[77];
     Godbout, 36; Mt. Albert, 7 (4[78]; 3[2]); St. Anne River, 1500
     ft., 1[77]; Ste. Anne des Monts, 3[2]; "Federal Mine," 1[77];
     Berry Mountain Camp, 1[77]; Berry Mountain Brook, 1[2]; Cascapedia
     River (Middle Camp, 2; Tracadie, 2; Square Forks, 1), 5[2].

     =Saskatchewan.= Poplar Point, Athabasca Lake, 1[75]; Fair Point,
     Athabasca Lake, 1[75]; Emma Lake, 1[74]; Harper Lake, 2[77];
     Livelong, 3[55]; Fairholme, 2[74]; Touchwood Hills, 2[7]; Indian
     Head, 1[86].

     =Yukon.= Hoole Canyon, 1; Teslin Lake (30 mi. N of, 1; Lake
     itself, 1; "near" the lake, 1; Mts. "near," 2; Snowden Mts., 2;
     Teslin Post, 2; Eagle Bay, 1; Morley Bay, 2; Nisutlin River, 1;
     Nisutlin Flats, 2; Wolf River, 1; Wolf Lake, 5), 21[77].


=Mustela erminea cicognanii= Bonaparte

Ermine

Plates 2, 3, 4, 9, 10 and 11

    _Mustela cigognanii_ [_sic._] Bonaparte, Charlesworth's Mag. Nat.
      Hist., 2:37, 1838.

    _Putorius vulgaris_, Emmons, Quadrupeds of Massachusetts, p. 44,
      1840.

    _Mustela pusilla_ DeKay, Zool. of New York, Pt. 1, Mammalia, p. 34,
      pl. 14, fig. 1, 1842. Type from New York State.

    _Putorius pusillus_, Audubon and Bachman, Vivip. Quadrupeds of N.
      Amer., 2:100, pl. 64, 1851 (pl. 1846) and erroneously labeled
      _Mustela fusea_, as pointed out on p. 102 of text.

    _Putorius cicognanii_, Baird, Mamm. N. Amer., p. 161, 1858.

    _Putorius richardsoni cicognani_, Bangs, Proc. Biol. Soc.
      Washington, 10; 18, figs. 4, 4a of pls. 1 and 2, and pl. 3, figs.
      2, 2a, February 25, 1896 (part).

    _Putorius cicognani_, Merriam, N. Amer. Fauna, 11:10, pl. 2, figs.
      3, 3a, 4, 4a and pl. 5, figs. 2, 2a, June 30, 1896.

    _Mustela cicognanii cicognanii_, Miller, U. S. Nat. Mus. Bull.,
      79:95, December 31, 1912; Bishop, Journ. Mamm., 4:26, February 9,
      1923.

    _Mustela cicognanii_, Jackson, Journ. Mamm., 3:15, February 8,
      1922.

    _Mustela erminea cicognanii_, Hall, Journ. Mamm., 26:77, February
      27, 1945; Hall, Journ. Mamm., 26:180, July 19, 1945.

     _Type._--No type specimen designated; type locality, eastern
     United States.

     The restriction of the type locality from the general region of
     northeastern North America, as given by Merriam (1896:10) to the
     less inclusive area of the eastern United States as earlier given
     by Bangs (1896:18) is supported by Bonaparte's remarks in
     connection with the proposal of the name _cicognanii_. He says
     (1838:37-38) "During my stay in the United States, I only saw a
     small species of _Mustela_, very common throughout the
     Union . . . ." This animal constituted basis for the name
     _cicognanii_ which name, he points out, is bestowed in order that
     the Americans ". . . should have constantly under their eye, this
     very common little animal, as the perpetual memorial . . ." to the
     Italian Governmental representative ". . . who, for upwards of
     fourteen years had served, in diplomatic and commercial
     concerns, . . . two countries, . . . so different . . . as the
     Roman and the United States. . . ." Clearly he had in mind
     principally, if not exclusively, the animal of the United States.

     _Range._--Transition and higher life-zones of northeastern United
     States south to Connecticut, central Pennsylvania and extreme
     northeastern Ohio; in Quebec and Ontario westward from the
     latitude of central Maine to Lake Nipigon and Lake of the Woods.
     See figure 25 on page 95.

     _Characters for ready recognition._--Differs from _M. e.
     richardsonii_ of both sexes, in that least width of color of
     underparts averages less than a third rather than two-fifths of
     greatest width of color of upper parts, in males skull less,
     instead of more, than 1.9 grams and basilar length less than 38,
     in females by 16 per cent lighter skull (0.92 versus 1.1 grams);
     from _M. e. bangsi_, in males hind foot less instead of more than
     40, linear measurements of skull averaging 11 per cent less (depth
     of skull at plane of molars 10.0 versus 11.4), in females
     averaging smaller, hind foot 30 versus 32 and depth of skull at
     plane of molars 8.6 versus 9.1.

     _Description._--_Size._--Male. Seven adults and subadults from New
     York and Pennsylvania, yield average and extreme measurements as
     follows: Total length, 266 (240-295); length of tail, 74 (66-80);
     length of hind foot, 36 (33-39). Hamilton (1933:294) gives the
     weight of 31 adults from New York as 81 (66-105) grams.

     Female: Twelve adults and subadults from Maine and the area south
     to central Pennsylvania, yield average and extreme measurements as
     follows: Total length, 243 (225-260); length of tail, 63 (55-72);
     length of hind foot, 29.8 (26-32). Hamilton (1933:294) gives the
     weight of 15 adults from New York as 54 (45-71) grams.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that underparts in summer Marguerite Yellow or even more whitish;
     least width of color of underparts averaging, in adult males from
     New York and Pennsylvania, 29 (27-32) per cent of greatest width
     of color of upper parts. Black tip of tail in same series
     averaging 42 (30-51) mm. which is 57 per cent of length of
     tail-vertebrae.

     _Skull._--Male (illustrated by 4 adults in table of cranial
     measurements, which see): See plates 2-4. As described in _Mustela
     erminea richardsonii_ except that: Weight, 1.5 (1.2-1.7) grams;
     basilar length, 35.7 (33.8-37.6).

     Female (illustrated by adult and subadults recorded in table of
     cranial measurements, which see): See plates 9-11. As described in
     _Mustela erminea richardsonii_ except that: Weight of 2 subadults,
     0.92 (0.86-0.98) grams; basilar length, 32.4 (31.4-33.3).

The skull of the male, in linear measurements, is approximately 13
(12-16) per cent smaller and 40 per cent lighter than in _M. e.
richardsonii_. In relation to the basilar length, the skull averages
slightly narrower, slightly shallower as measured in the vertical plane
touching the posterior borders of the last upper molars, and the
preorbital part is slightly longer. In skulls of females of
_cicognanii_, linear measurements average 3 (0-6) per cent less, the
weight is 16 per cent less and the teeth are 5 per cent shorter. In
relation to the basilar length, measurements of the skull are
approximately the same or slightly less in _cicognanii_.

In comparison with _bangsi_, the male sex in linear measurements of the
skull and teeth averages 11 per cent less than in _bangsi_ from Aitkin,
Minn., and 6 per cent less than in _bangsi_ from Elk River, but in
relation to the basilar length the preorbital region is larger. The
weight is approximately a fourth less. In females the measurements
average less, some being the same, and in relation to the basilar
length, the bullae are shorter and the skull is shallower. The weight
is about the same.

_Remarks._--In January, 1838, in Charlesworth's Magazine of Natural
History, C. L. Bonaparte proposed for three kinds of American weasels
the names _Mustela cicognanii_, _Mustela richardsonii_ and _Mustela
longicauda_.

In this paper Bonaparte indicates that he previously had written (for
his Iconografia della Fauna Italica ...) an account of _Mustela
cicognanii_ using this same name. Fasciola XXII of the Iconogr. d.
Fauna Italica, presenting his account of _Mustela_, like the English
paper was published in the year 1838. In his article in Charlesworth's
Magazine, Bonaparte refers to his book published [used the past tense]
in Rome but whether it actually appeared first I am unable to determine
and hence am uncertain which of the two constitutes the original
description.

Reference to the Italian account suggests as basis for the name _M.
cicognanii_, (1) specimens possibly seen in the United States by
Bonaparte, or (2) Godman's published account of the animal.

In the English publication, however, Bonaparte actually says that (1)
he saw the small species in the Union [= United States]. Also, he (2)
mentions his earlier written Italian account, (3) mentions that "all
the [American?] naturalists" used the name _M. vulgaris_ for this
animal, (4) incidentally mentions Godman's account, and (5) in naming
two other American species cites accounts of them by Richardson. Also,
Bonaparte in this English article makes clear that when he wrote [not
necessarily published] his Italian paper he did not know of the
existence of two of the three American species.

In the register of mammals at the British Museum of Natural History,
there appears:

  43.3.3.3 Mustela longicauda _Bonap_ N amer presented
                                      by Dr. J. Richardson
         4 Mustela Richardsonii Bonap        "
         5   "     Cicognanii Bonap          "

To the right of these entries there appears, in three lines, the
notation: "The three specimens examined by Prince Canino on which he
established the three species."

Every part of each of the above entries is in the hand writing of J. E.
Gray, in charge of the collections from 1824 to 1840 and associated
with them as Keeper until 1875. The three specimens are in good
condition considering their age. The catalogue or register number
shows, among other things, that they were entered in the register on
March 3, 1843.

Questions which might occur to anyone are:

(1) Was there a type specimen of _Mustela Cicognanii_ Bonaparte? If so
is it no. 43.3.3.5?

(2) If there was no type specimen was there a type locality? If so what
is it?

Among other things that may have bearing on these questions, are these:
Bonaparte in Charlesworth's Magazine appears to base the two names
_Mustela Richardsonii_ and _Mustela longicauda_ on Richardson's
published account of _Mustela erminea_. At any rate immediately
following each of the two names, Bonaparte writes "Nob. (_M. erminea_
Rich. F. Bor. Amer.)." Bonaparte's other, first newly proposed name,
_Mustela Cicognanii_, in Charlesworth's Magazine has following it only
"Nob. North America," although in a paragraph above he did point out
that this was the animal which all naturalists, at the time he was in
America, considered as _M. vulgaris_.

Turning to Richardson's account (Fauna Boreali Americana, ...
Quadrupeds, pp. 45-47. 1829) one finds that he recognized two species,
_M. vulgaris_ and _M. erminea_. Of the first he gives measurements "of
an old female killed at Carlton House." Of the second species he
distinguishes two varieties, the first represented by a specimen, of
which he gives measurements, "killed at Fort Franklin, Great Bear Lake"
and, the second variety "of a larger size, having a longer tail and
longer fore-claws" he indicates the size of by giving measurements of
a specimen taken "in the neighborhood of Carlton House."

The last variety is clearly the basis of Bonaparte's _M. longicauda_.
The specimen from which Richardson took his measurements I have been
unable to locate [no. 43.3.3.3 in the British Museum, appears to be
another specimen, although of the same subspecies and provided by
Richardson].

The first variety of Richardson's _Mustela erminea_, clearly is the
basis of Bonaparte's _M. Richardsonii_. The specimen from which
Richardson took his measurements may well be no. 43.3.3.4 now preserved
in the British Museum of Natural History, but I could not be certain
about this.

Richardson's _M. vulgaris_ is accompanied by measurements of a female
which I have ascertained to my full satisfaction is the identical
specimen now bearing catalogue number 43.3.3.5 said by Gray to be the
specimen on which Bonaparte based his name _Mustela cicognanii_.

Gray probably saw his guest, Bonaparte, at work on these weasels and
Gray's own written indication perhaps should be accepted at its face
value. I found only 4 Richardson specimens of North American weasel in
the British Museum in 1937 and it is conceivable that Bonaparte, 100
years before, actually had at hand only one specimen each of two kinds
and 2 specimens of the third. This I think is not an important
consideration, though, for Gray says just which specimens did serve as
basis for Bonaparte's names and there is only one specimen for each
name according to Gray.

But I wonder if a type specimen can be _made_ in this way? That is to
say, after a name is published in a manner which makes it available,
and if two or more specimens of the kind of animal involved, were, or
may have been, available to the describer, can a person, even the
author, himself, _make_ a type specimen by saying that one particular
specimen is beyond doubt the specimen on which a given name was
established even though no particular specimen was designated in the
original description? I incline to the view that a specimen so
designated would at most be only a lectotype, unless it were a cotype.

However, if a holotype can be _made_ by action such as Gray took, then
(1) is no. 43.3.3.3 the type specimen of _Mustela longicauda_ Bonaparte
and, (2) is no. 43.3.3.4 the type specimen of _Mustela Richardsonii_
Bonaparte?

Incidentally, _Mustela longicauda_ Bonaparte whether based on no.
43.3.3.3 or on Richardson's account will continue in its present
application. The same is true of _Mustela richardsonii_. If the basis
of _Mustela cicognanii_ Bonaparte [the diagnosis in the Iconografia d.
Fauna Italica ... makes it clear that the name applies to the
_short-tailed_ species] was a weasel from the eastern United States or
a description of a weasel or weasels from there, the name will continue
in its present application. If, instead, the name is based on no.
43.3.3.3 (from Carlton House, Saskatchewan) or on Richardson's account
of _M. vulgaris_, the name will apply to a different subspecies (now
called _richardsonii_ and _richardsonii_ will fall as a synonym of
_cicognanii_) and the ermine of the eastern United States will take the
next available name. Bonaparte probably named (in manuscript at least)
_cicognanii_ before he ever saw the specimen in the British Museum.
This is indicated by his statement in Charlesworth's Magazine (1838:37)
that "I have _now_ [Italics mine] found two [other] American
species. . . ." Whereas the names _richardsonii_ and _longicauda_ are
based on Richardson, the name _cicognanii_, even if it dates from the
account in Charlesworth's Magazine, appears to have a composite basis
composed at the very least of (1) animals seen by Bonaparte in the
United States, and (2) those called _vulgaris_ by some other authors.
Conceivably the specimen no. 43.3.3.3 in the British Museum, was part
of the basis. From the nature of the case it can be argued that there
could be no type and that if someone should bring to light a specimen
in, say, Philadelphia, bearing the notation "this is the specimen seen
in the United States by Bonaparte" it would immediately become as
important as the one in London. Any American weasel or weasels (then
alive or preserved in a zoölogical collection) that Bonaparte saw in
the United States probably were of the eastern United States. Bangs
(1896:18-21), for one, previous to the present consideration of the
name _cicognanii_, restricted it to the ermine of the eastern United
States. Consequently, the name _cicognanii_, in the present account is
applied to the ermine of the eastern United States. In my opinion there
was and is no type. Almost certainly there was no type if the Fauna
Italica appeared before the account in Charlesworth's Magazine did.

     _Specimens examined._--Total number, 172, arranged alphabetically
     by provinces and states, then (except where indication is given to
     the contrary) by counties from north to south within each state or
     province. Unless otherwise indicated, specimens are in the U. S.
     National Museum.

     =Connecticut.= _Windham County_: S. Woodstock, Woodstock Lake,
     1[2]. _Hartford County_: Windsor, 1[5]. _New London County_:
     Liberty Hill, 3[75].

     =Maine.= _Aroostook County_: Quimby, 1[75]; Ashland 2[75].
     _Piscataquis County_: tableland on top of Mt. Katahdin, 1; Chimney
     Pond, 3; T. 5, R. 13, 3[5]; "vicinity of Chesnucook," 1[5]; T. 4,
     R. 13, 1[5]; Moosehead Lake, 7[75]; Grenville, 10[75]; Barnard, 3
     (1[86]). _Penobscot County_: South Twin Lake, 1[2]; Lincoln, 11
     (7[1], 2[14], 2[50]). _Franklin County_: Seven Pond Township,
     7[75]. _Oxford County_: Umbago Lake, 1[75]; Upton, 4[86]; Bethel,
     1[75]. _Hancock County_: Bucksport, 17[75]; Naskeag, 1. _Lincoln
     County_: Booth Bay, 1[5].

     =Massachusetts.= _Middlesex County_: Wilmington, 2; Burlington, 6
     (1[75]); _Worcester County_: Cambridge, 5 (1[5], 3[75]); Sterling,
     1[5]. _Plymouth County_: Middleboro, 7 (1[75]).

     =New Hampshire.= _Carroll County_: Ossipee, 5. _Rockingham
     County_: Greenland, 1[76]. _Cheshire County_: Dublin, 1.

     =New York.= _St. Lawrence County_: Ogdensburg, 1[74]. _Franklin
     County_: Malone, 1[58]. _Lewis County_: Locust Grove, 1. _Warren
     County_: Lake George, 1. _Montgomery County_: Amsterdam, 1.
     _Albany County_: Albany, 1[80]. _Rensselaer County_: Berlin, 2[2];
     Schoharie, 1[2]. _Thompkins County_: Cascadilla Creek, Ithaca,
     1[58]. _Allegany County_: Ford Brook, Wellsville, 1[58]. _Ontario
     County_: Phelps, 1[50]. _Cattaraugus County_: Cattaraugus, 1[5].

     =Ontario= (localities locally north to south, then west to east).
     _Thunder Bay Dist._: Grand Bay, Lake Nipigon, 5[86]; Macdiarmid,
     2[86]; Oscar, 2[14]; 20 mi. SW Fort Williams, 1[76]; Michipicoten
     Island, 3[104]. _Algoma Dist._: Michipicoten, 1; Franz, 1[74];
     Pancake Bay, 2[77]. _Parry Sound Dist._: French River, Georgia
     Bay, 1[2]; Seguin Falls, Twp. Montieth, 1[86]. _Sudbury Dist._:
     Casselman, Rathbun Twp., 1[86]. _Nipissing Dist._: Smoky Falls,
     near Kapuskasing, 4[86]; Franks Bay, Lake Nipissing, 1[86].
     _Haliburton County_: Gooderham, 1[60]. _Simcoe County_: Orillia,
     1[2]; no locality more definite than county, 1[60]. _Carleton
     County_: Britannia, 5 mi. W Ottawa, 1[77]; Ottawa, 1[77]; Constant
     Bay, NE? of Ottawa, 1[77]. _Wellington County_: Mt. Forest, 2[75];
     Guelph, 1[31]. _Addington County_: Buckshot Lake, Abinger Twp.,
     1[86]. _Fontenac County_: Clear Lake, Arden, 1[77].

     =Pennsylvania= (by counties from west to east). _Crawford County_:
     North Shenango Township, Pymatuning Swamp, 2[9]; Linesville (3 mi.
     NW, 1; 3-1/2 mi. W, 2; 3 mi. W, 1; 2 mi. SW, 1; 7-1/2 mi. SW, 1)
     6[9]. _Potter County_: Cherry Springs Farm, Abbott Township, 1; 3
     mi. S Inez, South Fork Sinnamahoning Creek, 1[9]. _Sullivan
     County_: Lopez, 1[74]. _Lackawanna County_: Scranton, 1[1]. _Wayne
     County_: Waymart, 1.

     =Quebec= (west to east). _Labelle County_: Kamika [= Kiamika]
     Lake, 2[77]; Lacoste, 2[77]; Trout Lake, probably in this county,
     2[77]. _Megantic County_: Black Lake, 1[77].

     =Rhode Island.= _Newport County_: Middletown, 2[5].

     =Vermont.= _Lamoille County_: Mt. Mansfield, 1. _Windsor County_:
     Barnard, 1[5].


=Mustela erminea bangsi= Hall

Ermine

Plates 2, 3, 4, 9, 10 and 11

    _Mustela erminea bangsi_ Hall, Journ. Mamm., 26:176, July 19, 1945.

    [_Putorius_] _cicognani_, Mearns, Bull. Amer. Mus. Nat. Hist.,
      3:235, June 5, 1891.

    _Putorius richardsoni cicognani_, Bangs, Proc. Biol. Soc.
      Washington, 10:18, February 25, 1896 (part).

    _Putorius cicognanii_, Cory, Mamm. Illinois and Wisconsin, p. 375,
      1912.

    _Mustela cicognanii_, Aldous and Manweiler, Journ. Mamm., 23:250,
      August 13, 1942.

    _Mustela cicognanii cicognanii_, Bailey, N. Amer. Fauna, 49:169,
      January 8, 1927; Leraas, Journ. Mamm., 23:344, August 13, 1942.

     _Type._--Male, subadult, skull and skin; no. 11541, D. R. Dickey
     Coll.; Elk River, Sherburne County, Minnesota; November 1, 1925;
     obtained by Bernard Bailey, original no. A 606.

     The skull is complete and the teeth all are present and entire.
     The skin is well made and in a good state of preservation.

     _Range._--Southern Manitoba, northeastern North Dakota, the whole
     of Minnesota, Wisconsin and Michigan and northern Iowa. See figure
     25 on page 95.

     _Characters for ready recognition._--Differs from _M. e.
     richardsonii_, in that, in both sexes, least width of color of
     underparts averages about a third, instead of two-fifths, of
     greatest width of color of upper parts, and in that skulls of
     males are a fifth or more lighter, basilar length averaging less
     than 40; from _M. e. cicognanii_, in that hind foot more than 40
     in males, averaging 32 versus 30 in females, and in larger skull,
     depth of skull at plane of molars being 11.4 versus 10.0 in males
     and 9.1 versus 8.6 in females.

     _Description._--_Size._--Male: Twelve adult and subadult males
     from Aitkin, Minnesota, yield average and extreme measurements as
     follows: Total length, 316 (291-341); length of tail, 87 (70-101);
     length of hind foot, 43 (40-44). Two adults from Aitkin each weigh
     170 grams.

     Four adult and subadult females from Elk River and Fort Snelling,
     Minnesota, yield average and extreme measurements as follows:
     Total length, 249 (240-260); length of tail, 61 (55-65); length of
     hind foot, 32 (30-33).

     _Color._--As described in _Mustela erminea richardsonii_ except
     that, least width of color of underparts averaging, in males from
     Minnesota, 32 (19-51) per cent of greatest width of color of upper
     parts. Black tip of tail in 12 male topotypes in white winter
     pelage averaging 52 (45-58) mm. which is 60 (53-66) per cent of
     length of tail-vertebrae.

     _Skull._--Male (based on adults from Aitkin): See measurements and
     plates 2-4. As described in _Mustela erminea richardsonii_ except
     that: Weight of 2 adults from Aitkin, 2.2, 2.3 grams (9 subadults
     from T. 61 N, R. 26 W, average 1.95 grams); basilar length, 39.7
     (38.5-40.7); length of tooth-rows rarely more (usually less) than
     length of tympanic bulla.

     Female (based on adults from Minnesota as listed in table of
     cranial measurements, which see): See plates 9-11. As described in
     _Mustela erminea richardsonii_ except that: Weight, of a subadult
     from T. 61 N, R. 26 W, 0.91 grams; basilar length, 32.8
     (31.8-33.6); breadth of rostrum rarely equal to as much as 30 per
     cent of basilar length.

From _richardsonii_, topotypes of _bangsi_ differ in that cranial
measurements in males are approximately 7 (5-9) per cent less, linear
measurements of teeth are 10 (9-11) per cent less and the skull is a
fifth lighter. In relation to basilar length the tympanic bullae of
_bangsi_ are longer. Skulls of females are individually
indistinguishable, those of _bangsi_ averaging approximately 1 per cent
less in linear measurements. Comparison with the smaller cicognanii is
made in the account of that subspecies.

_Remarks._--Before the subspecific name _bangsi_ was proposed,
individuals of this subspecies ordinarily were recorded in the
literature as _Mustela cicognanii_. The best single lot of material is
in the zoölogical collection of the University of Wisconsin. The late
naturalist Albert Lano preserved a large share of the material from
Minnesota. The large series from Elk River of that same state was
mostly collected by Bernard Bailey although his Aunt, Anna (Bailey)
Mills, and her brother the late Vernon Bailey, at an earlier time saved
some specimens from Elk River. The name _bangsi_ was proposed in
recognition of the superior work done on American weasels by the late
Outram Bangs.

From the range of _M. e. invicta_ in the Rocky Mountains, that of
_bangsi_ is separated by the Great Plains from a large part of which
region the species is unknown. _M. e. bangsi_ differs from _invicta_ in
greater degree of sexual dimorphism in size, and in each sex by larger
size, narrower light-colored underparts, and deeper braincase as
measured at the anterior margin of the basioccipital. In _bangsi_ the
braincase is deeper relative to the length of the skull as well as, of
course, actually deeper.

Of the two subspecies whose ranges do meet that of _bangsi_, it more
closely resembles _richardsonii_ than _cicognanii_. From
_richardsonii_, especially from southeastern populations of the same in
which the skull is of the same size as in _bangsi_, the latter differs
in longer hind feet. This is an average difference and by one
interpretation the animals here referred to _bangsi_ might be lumped
with some of the populations from the southeastern part of the range of
_richardsonii_ and the whole lot treated as intergrades between
_richardsonii_ and _cicognanii_. Nevertheless, the animals here
referred to bangsi are not geographically intermediate between
_richardsonii_ and _cicognanii_ and this consideration had much to do
with the decision to recognize as a separate subspecies the animals
here named _bangsi_.

Within the range of the subspecies there is some geographic variation;
the hind feet of animals from Iowa average slightly shorter than those
of animals from Minnesota and Wisconsin but are nowhere nearly so short
as in _cicognanii_ at the same latitude in the eastern United States.

It is noteworthy that the few specimens seen from Isle Royal have the
long hind feet of _bangsi_ and not the short hind feet of _cicognanii_
which occurs all along the northern mainland.

Because an oft cited record of occurrence even though erroneous, has a
way of being repeated in later works, attention is here called to the
alleged occurrence of this ermine in northwestern Ohio at New Bremen.
Henninger (1921:239) published the original account of the supposed
occurrence but as I pointed out in 1937 (p. 304), the specimen
concerned proved upon examination to be a female of _Mustela frenata
noveboracensis_. Henninger was misled probably by the short tail; the
end of the tail had been lost and healed over before the animal's
death. The present study has revealed that _M. erminea_ everywhere east
of the Cascade Mountains assumes a white winter coat. Had this been
known when Henninger obtained his specimen he probably would not have
wrongly identified the animal from New Bremen which was in the brown,
winter pelage.

     _Specimens examined._--Total number, 222, arranged alphabetically
     by provinces and states and, arranged from north to south, by
     counties in each state. Unless otherwise indicated, specimens are
     in the University of Wisconsin Museum of Zoölogy.

     =Iowa.= _Dickinson County_: W side Lake Okobogie, 1[48].
     _Winnebago County_: Lake Mills, 7[65]. _Worth County_: Northwood,
     1[65]. _Clay County_: "Dewey's Pasture, near Ruthven," 1[76].

     =Manitoba.= Aweme, 4[47]; Red River Settlement, 1[91].

     =Michigan.= _Isle Royal_: Tobin Harbor, 1[76]; Bell Isle, 1[76];
     Washington Harbor, 3[76]. _Ontonagon County_: Ontonagon, 2 (1[76],
     1[14]); T. 51N, R. 43W, S. 17, Porcupine Mts., 1[76]. _Gogebic
     County_: Little Girls Point, 5[76]; Ironwood, 1[76]. _Iron
     County_: no locality more definite than county, 1[76]. _Luce
     County_: Tahquamenon River Falls, 1[91]. _Chippewa County_: Sault
     Ste. Marie, 2[76]. _Emmet County_: Wilderness State Park, 2[76].
     _Cheboygan County_: Univ. Mich. Biol. Station, 1[76]. _Washtenaw
     County_: Ann Arbor, 1[76].

     =Minnesota.= _Kittson County_: no locality more definite than
     county, 1[2]. _Roseau County_: Deer Township, 1[14]; Falun
     Township, 2[14]. _Marshall County_?: Moose River, 5[93]; Warren,
     definitely in Marshall County, 1[93]. _Cook County_: Grand Marais,
     3 (2[76], 1[14]). _St. Louis County_: 2 mi E Babbitt, 14[93];
     Burntside [= Burnside] Lake, 1[91]. _Itasca County_: T. 61N, R.
     26W, 23. _Clay County_: Moorhead, 3[9]. _Aitkin County_: Aitkin,
     13 (11[60], 1[7], 1[4]). _Otter Tail County_: Arthur, 3[60]; Ten
     Mile Lake, 1[76]; Parkers Prairie, 2[75]. _Chisago County_: North
     Branch, 1[60]. _Sherburne County_: Elk River, 42 (16[91], 5[14],
     20[59], 1[74]). _Hennepin County_: Lake Minnetonka, 1[75];
     Minneapolis, 1[91]; Fort Snelling, 5 (4[2], 1[60]).

     =North Dakota.= _Pembina County_: Walhalla, 1[91]. _Nelson
     County_: Stump Lake, 1[91]. _Eddy County_: Brantford, 2[76].

     =Wisconsin.= _Douglas County_: T. 44N, R. 13W, 1; Gordon, 1.
     _Bayfield County_: Brinks Camp, Washburn, 1[2]; "near Cable," 1.
     _Ashland County_: Bear Lake, 2. _Iron County_: Fisher Lake, 4;
     Mercer, 5. _Vilas County_: Mamie Lake, 16[91]; Ox Bow Lake, 1[91].
     _Oneida County_: Tomahawk Lake, 1[60]. _Langlade County_: T. 34N,
     R. 11E, 3. _Rush County_: Ladysmith, 1. _Dunn County_: Colfax, 2.
     _Door County_: Mink River, Ellison Bay, 1[76]. _Dodge County_: Fox
     Lake, 1[50]; Beaver Dam, 12[50].


=Mustela erminea invicta= Hall

Ermine

Plates 2, 3, 4, 9, 10, 11 and 41

    _Mustela erminea invicta_ Hall, Journ. Mamm., 26:75, February 27,
      1945; Hall, Journ. Mamm., 26:180, July 19, 1945.

    _Putorius cicognanii_, Preble, N. Amer. Fauna, 27:230, October 26,
      1908.

     _Type._--Male, subadult, skull and skin; no. 101122, Mus. Vert.
     Zoöl.; Benewah, Benewah County, Idaho; October 24, 1926; obtained
     by William T. Shaw.

     The skull has a hole in the right squamosal bone on the floor of
     the braincase, and lacks the hamular process of the left
     pterygoid. The postmolar part of the right lower jaw is missing.
     The teeth all are present and entire. The skin is in white, winter
     pelage, well made, and in a good state of preservation.

     _Range._--Central Rocky Mountain region from Jasper Park south
     over Alberta, southeastern British Columbia, Washington east of
     the Cascades, and north and central Idaho and northwestern
     Montana. See figure 25 on page 95.

     _Characters for ready recognition._--Differs from _M. e.
     richardsonii_, in males, by skull lighter than 1.9 grams, mastoid
     breadth less than 19.9, depth of skull at anterior margin of
     basioccipital less than 12.4, in females by corresponding
     measurement of depth less than 10.1, and weight of skull less than
     one gram; from _M. e. fallenda_, in both sexes, by upper lips
     white (not brown), in males by skull averaging longer (37.0 versus
     35.7), in females by breadth of rostrum less, instead of more,
     than 30 per cent of basilar length; from _M. e. streatori_,
     _gulosa_, and _muricus_ by hind foot more than 36 and basilar
     length more than 35 in males and by hind foot more than 29.5 and
     basilar length more than 30.5 in females; further distinguished
     from _streatori_ by white (not brown) upper lips and from _gulosa_
     by black tip of tail more than half length of tail-vertebrae.

     _Description._--_Size._--Male: Ten adults and subadults from
     central Idaho County yield average and extreme measurements as
     follows: Total length, 291 (272-328); length of tail, 86 (75-100);
     length of hind foot, 39.9 (38-44).

     Female: Five adults and subadults from the same locality yield
     average and extreme measurements as follows: Total length, 255
     (245-270); length of tail, 71 (68-76); length of hind foot, 32.3
     (32-33).

     _Color._--As described in _Mustela erminea richardsonii_ except
     that underparts in summer Marguerite Yellow or more whitish; least
     width of color of underparts averaging, in four females from Idaho
     and Montana, 38 (33-43) per cent of greatest width of color of
     upper parts. Black tip of tail in same specimens 38 (31-42) mm.
     which is 57 (52-65) per cent of length of tail-vertebrae.

     _Skull._--Male (5 adults from Idaho County): See measurements and
     plates 2-4. As described in _Mustela erminea richardsonii_ except
     that: Weight, 1.5 (1.4-1.7) grams; basilar length, 37.0
     (35.8-39.8).

     Female (illustrated by adult and 4 subadults in table of cranial
     measurements, which see): See plates 9-11. As described in
     _Mustela erminea richardsonii_ except that: Weight, 0.72 (0.7-0.9)
     grams; basilar length, 32.2 (31.6-32.8).

From _fallenda_, _invicta_ differs in that the skull of the male has a
relatively narrower rostrum and relatively shallower braincase. Females
show the same differences but the degree of difference is about as
great again as in males. The teeth are almost exactly the same size in
the two subspecies. The weight is the same in males but in females
_invicta_ is 18 per cent heavier.

From _streatori_, _invicta_ differs in that males average larger in
every measurement taken except that the anteroposterior diameter of the
inner moiety of M1 is less; 36 per cent heavier; linear measurements of
the skull are about 5 per cent larger and those of the teeth, with the
one exception noted, about 6 per cent larger; relative to the basilar
length the tympanic bullae are longer and the rostrum is relatively
narrower. In females, measurements of the skull average 8 per cent more
and those of the teeth 7 per cent more except that, as in males, the
inner lobe of M1 is actually shorter. Females of _invicta_ are 12 per
cent heavier; relative to the basilar length the skull is narrower
throughout and the tooth-rows are shorter than in _streatori_.

From _gulosa_, _invicta_ differs in that males average larger (about 12
per cent) in every measurement taken, excepting the anteroposterior
diameter of M1 which is the same; 50 per cent heavier; relative to the
basilar length the length of the tooth-rows and interorbital breadth
are less. In females the inner lobe of M1 is smaller but every other
measurement taken of the skull and teeth is more, _invicta_ averaging
about 8 per cent larger and 22 per cent heavier; relative to the
basilar length, the tooth-rows are shorter and the skull is narrower
interorbitally, through the rostrum and across the zygomata.

From _murica_, _invicta_ of corresponding sex differs in being larger
in every measurement taken; males average 17 per cent larger in cranial
measurements, 13 per cent larger in dental measurements and are 83 per
cent heavier; corresponding percentages for females are 11, 9 and 20.
Exception must again be made for the anteroposterior diameter of the
inner lobe of the last upper molar which is less in females, and only
slightly more in males. In males of _invicta_ the tympanic bullae are
longer in relation to the basilar length.

From the geographically remote _cicognanii_, skulls of both males and
females of _invicta_ are to me individually indistinguishable. There
is, nevertheless, an average difference not apparent to the eye between
skulls of males. If the length of the tooth-rows be taken as a standard
(100 per cent), the rostrum, of _invicta_, as measured across the
lacrimal processes is broader (89 rather than 84 per cent) but the
width across the fourth upper premolars is less, 94 rather than 97 per
cent of the length of the tooth-rows.

Since the skull of _invicta_ closely resembles that of _cicognanii_, it
follows that _invicta_ differs from _richardsonii_ and _bangsi_ in
about the manner described in the account of _cicognanii_.

_Remarks._--Animals of this subspecies in advance of the present study
generally were recorded in the literature under the name _Mustela
cicognanii_. The difficulty in distinguishing individual specimens of
_invicta_ on morphological grounds from those of the geographically
remote _M. e. cicognanii_ should not be taken to indicate that the
populations do not differ appreciably. Actually they differ in several
characters although in no one of these is the degree of difference
sufficient to allow of using it alone as a certain means of diagnosis.
In _invicta_, as compared with _cicognanii_, the light-colored
underparts are wider in relation to the dark-colored upper parts and
the tail is longer by 4 per cent relative to the head and body. Given a
population of each of the two subspecies, in which the skull is of the
same mass, the hind feet are longer in _invicta_, there is more sexual
dimorphism in size, and the anterior part of the skull differs in some
particulars as just described in the comparison of the skull of
_invicta_ with other forms. Nevertheless, each of these differences is
of an average sort. Therefore, and because overall size is about the
same in the two subspecies concerned, one or a few specimens from, say,
central Idaho, can be distinguished from animals from western
Pennsylvania only with difficulty, if at all. The close resemblance of
skulls of _invicta_ and _cicognanii_ may be a function of their living
at approximately the same latitudinal position in a climate that has
marked seasonal variation.

Intergradation with _richardsonii_ is complete and gradual; in one
sense _invicta_ is but little more than a small _richardsonii_.
Intergradation with _fallenda_ is shown by several specimens. These two
races differ in large degree in color, and in size and shape of the
skull of females. Although the geographic area where intergradation in
color occurs is fairly wide, the area in which intergradation in
cranial characters in females occurs, appears, from the inadequate
material available, to be much narrower. Intergradation occurs freely
in Washington with _streatori_ but with _muricus_ so far as known only
in the Bitterroot and nearby mountains of northwestern Montana. The
Snake River Plains and low country along much of the Columbia River
appears to be uninhabited by weasels of the species _erminea_ and hence
there is opportunity for intergradation only in the mentioned area of
Montana.

     _Specimens examined._--Total number, 177, as follows. Arranged
     alphabetically by provinces and states then by localities from
     north to south in each province and by counties from north to
     south in each state. Unless otherwise indicated, specimens are in
     the United States National Museum.

     =Alberta.= Jasper House, 4[77]; Shovel Pass, 2[77]; Jasper Park,
     10[77]; head of Smoky River, 9; Henry House, 2 (1[77]); Blindman
     River, 1[2]; forks of Blindman River and Red Deer River, 2 (1[60],
     1[75]); "near Red Deer, Red Deer River," 1[77]; Red Deer River, 2
     (1[2], 1[60]); Red Deer, 2[60]; Rosebud, 2[77]; Prairie, 3000 ft.,
     1; Didsbury, Little Red Deer River, 1; Canadian Nat'l Park, 1[60];
     Canmore, 1; Banff, 1[60]; High River, 1[86]; "Waterton Lake Park"
     in Alberta, 6[77].

     =British Columbia.= Grand Forks of Fraser River, 1; Canoe River,
     1[77]; Field, 1; Glacier, 1[58]; E side Beaverfoot Range,
     4000-4500 ft., 6 mi. SE Fraser Creek, 8[74]; Wentworth Lake,
     1[31]; Revelstoke, 2 (1[77], 1[60]); Spillimacheen[e]en River,
     2[2]; Sicamous, 2; Albert River, 7000 ft., 1[2]; Lumby, Creighton
     Valley, 1[31]; Okanagan, 4 (2[75], 1[94], 1[2]); Kettle River
     Lake, Gold Range, 4000 ft., 1; Crows Nest Station, 1[74]; Yale
     District, 3; Fort Hope, 1; Chilliwack Lake, 1[77]; Skagit, 2
     (1[77], 1[31]); Skagit Valley, 1[77]; Skagit Summit, 1[77];
     Lightning Lakes, 2 mi. N International Boundary, 3;
     Osoyoos-Bridesville Summit, 2; Westbridge, 1[77]; Rossland, 5[77];
     Creston, mouth Goat Creek, 3[77]; Yahk, 4[77].

     =Idaho.= _Bonner County_: Coolin, 4. _Benewah County_: Benewah,
     1[55]. _Idaho County_: "Pete Kings, Lochsa River," 1[97]; 2 mi.
     SSE Selway Falls, 1900 ft., 1[8]; 4 mi. SW Selway Falls, 5800 ft.,
     3[8]; Newsome Cr., 12 mi. above jct. with S Fk. Clearwater River,
     2[74]; Iron Mt., to 14 mi. W thereof, 24[74]; Pilot Cr., 3/4 to
     2-1/2 mi. above Newsome Cr., 4[74]; Sawmill Cr., 1-1/4 mi. W
     Newsome, 1[74]; between Selway River and S. Fk. Clearwater R.,
     4[74].

     =Montana.= _Teton County_ (of old arrangement of counties): Many
     Glacier, 4900 ft., 1[74]; Duck Lake, 6 mi. NE St. Marys Lake, 1;
     St. Marys, Glacier Park, 1[76]; Lower St. Marys Lake, 1[2].
     _Flathead County_: Stanton Lake, 5. _County_ in question: Bitter
     Root Mts., 1. _Ravalli County_: Tin Cup District, 1[74]; Bass
     Creek, 6800 ft., NW of Stevensville, 1; Capitan Peak, 7000 ft., 1;
     Darby, 2[74]; Girds Creek, 1[74]; Charlos Heights, 2[74].

     =Washington.= _Whatcom County_: Twin Lakes, Winchester Mts., 3
     (1[10]); Chilliwack River, 2600 ft., 2; Cooper Creek, near head,
     4500 ft., Hannegan Pass, 1; Cooper Cr., 4300 ft., Hannegan Pass,
     1[10]; Beaver Creek (2500 ft., and at McMillan Ranch, 1700 ft.),
     2; Barron, Bornite Mine, 5000 ft., 1. _Okanogan County_: Tungsten
     Mine, 6800 ft., Bauerman Ridge, 4; Hidden Lakes, 4100 ft., 1; West
     Fork Pasayten River, 4700 ft., 1. _Stevens County_: Orin, 1[51].
     _Pend Oreille County_: Ione, 2[51]. _Chelan County_: Lake Chelan,
     1[46].


=Mustela erminea alascensis= (Merriam)

Ermine

Plates 2, 3, 4, 9, 10 and 11

    _Putorius richardsoni alascensis_ Merriam, N. Amer. Fauna, 11:12,
      pl. 2, figs. 2, 2a, June 30, 1896.

    _Putorius cicognanii alascensis_, Miller, U. S. Nat. Mus. Bull.,
      79:96, December 31, 1912; Swarth, Univ. California Publ. Zoöl.,
      7:140, January 12, 1911.

    _Mustela erminea alascensis_, Hall, Proc. Biol. Soc. Washington,
      57:36, June 28, 1944; Hall, Journ. Mamm., 26:180, July 19, 1945.

     _Type._--Male, adult, skull and skin; no. 74423, U. S. Nat. Mus.,
     Biol. Surv. Coll.; Juneau, Alaska; August 22, 1895; obtained by
     Clark P. Streator, original no. 4806.

     The skull shows malformation of the frontal sinuses due to
     parasites and lacks osseous tissue where the parasitic infestation
     was localized. The left exoccipital condyle and adjacent region is
     less developed than the right and the posterior part of the skull
     is bent slightly to the left. Otherwise the skull is unbroken. The
     teeth all are present and entire. The skin is in the brown summer
     coat, fairly well made and in a good state of preservation. A few
     white hairs persist where the proximal line of the black hair of
     the tip of the tail meets the distal line of the brown hair.

     _Range._--Mainland of southeastern Alaska from Lynn Canal south to
     include Mitkof, Zarembo, Wrangel and Revillagigedo islands. See
     figures 25, 26 on pages 95 and 134.

     _Characters for ready recognition._--Differs from _M. e. arctica_
     and _haidarum_, in both sexes, by proximal two-thirds of under
     side of tail colored same as upper parts rather than same as
     underparts and interorbital breadth less, instead of more, than
     distance between glenoid fossa and posterior border of external
     auditory meatus; from _M. e. salva_, in males, by overall depth of
     braincase including tympanic bullae less than 89 per cent of
     orbitonasal length, females not individually distinguishable but
     averaging shallower through the braincase; from _M. e. initis_,
     _celenda_ and _seclusa_ by interorbital breadth less than distance
     between glenoid fossa and posterior border of external auditory
     meatus (females of _initis_, _celenda_ and _seclusa_ unknown);
     further from _initis_ by total length less than 317 and black tip
     of tail less than 57 per cent of length of tail-vertebrae; further
     from _celenda_ by chest white, not mostly covered by brown patch.

     _Description._--_Size._--Male: Eight adults from Windham, Alaska,
     yield average and extreme measurements as follows: Total length,
     298 (288-315); length of tail, 88 (84-94); length of hind foot,
     41.3 (37-44).

     Female: Two adults from Juneau and Helm Bay measure, respectively,
     as follows: Total length, 258, 258; length of tail,----, 76;
     length of hind foot, 32, 34.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that least width of color of underparts averaging, in five
     females, 42 (35-53) per cent of greatest width of color of upper
     parts. Black tip of tail in same specimens averaging 36 (30-40)
     mm. which is 49 (48-53) per cent of length of tail-vertebrae.

     _Skull._--Male (based on 8 adults from Windham): See measurements
     and plates, 2-4. As described in _Mustela erminea richardsonii_
     except that: Weight, 1.8 (1.5-2.6) grams; basilar length, 37.5
     (36.5-38.9); length of tooth-rows more or less than (about same
     as) length of tympanic bulla.

     Female (based on 5 adults, from localities listed in the table of
     cranial measurements): See measurements and plates 9-11. As
     described in _Mustela erminea richardsonii_ except that: Weight,
     0.96 (0.7-1.1) grams; basilar length, 32.7 (31.9-33.2); breadth of
     rostrum more or less than (about equal to) 30 per cent of basilar
     length.

From _richardsonii_, _alascensis_ differs in that the skull of the male
averages smaller in every measurement taken and is 28 per cent
lighter. Relative to the basilar length, the orbitonasal length is more
and the braincase is shallower as measured at the anterior end of the
basioccipital. The four adult females seen of _alascensis_ are more
variable than those of _richardsonii_ and average smaller in some
measurements and larger in others but give no proof of any consistent
difference.

From _haidarum_, _alascensis_ differs in that the rostrum and entire
preorbital part of the skull is actually as well as relatively much
smaller in both sexes. In males of _alascensis_ the length of the
skull, and other cranial measurements of length, is more. In males, the
mastoid breadth and zygomatic breadth are about the same as in
_haidarum_, as also is the weight. M1 is larger but m1 and P4 are
smaller. In females the anteroposterior extent of the inner moiety of
M1 and length of tympanic bulla are about the same in the two
subspecies but all other cranial and dental measurements in
_alascensis_ are less. It is 29 per cent lighter. The difference in the
preorbital region is of about the same degree as in the males.

Comparisons of the skull with those of _arctica_, _salva_, _initis_,
_celenda_, and _seclusa_ are made in the accounts of those subspecies.

_Remarks._--The relatively few specimens known of this race seem always
to have been referred to in the literature by the name _alascensis_ and
the nomenclatural history is therefore simple. The original materials
were obtained by the collector Clark P. Streator and the additional
series of skeletons, one with skin, from Windham were procured by
Stanton Price, a resident there.

The subspecies is well differentiated from both _arctica_ and
_richardsonii_. Although actual intergrades are lacking between
_alascensis_ and the two races just mentioned I have no doubt that
intergradation occurs with _richardsonii_ and think it probably does
also with _arctica_.

The assignment of the three females from Mitkof Island, Zarembo Island,
and Loring on Revillagigedo Island, is tentative because each is so
young as not to show diagnostic cranial characters. The two other
specimens from Revillagigedo Island (Carroll Inlet), labeled as males,
are in white winter pelage. Only one, no. 136358, a subadult, is
accompanied by a skull. The small size of each specimen, and its
cranial characters which are intermediate between those of males and
females of _alascensis_ of the adjacent mainland, indicate the
existence of a distinct race of weasel on Revillagigedo Island. On the
chance that the one specimen with a skull is a dwarf, or is wrongly
sexed as seems improbable, the population is tentatively referred to
_alascensis_.

[Illustration: FIG. 26. Map showing known occurrences and probable
geographic ranges of the subspecies of _Mustela erminea_ in
southeastern Alaska.]

     _Specimens examined._--Total number, 24, arranged by localities
     from north to south. Unless otherwise indicated, specimens are in
     the Museum of Vertebrate Zoölogy, University of California.

     =Alaska.= Juneau, 5[91]; Taku River, 1; Windham, 9; Mitkof Island,
     1; St. John Harbor, Zarembo Island, 1; Wrangel, 1[91]; Helm Bay,
     Cleveland Peninsula, 1; Cleveland Peninsula, 2[91]; Revillagigedo
     Island, Carroll Inlet, 2[91]; Loring, 1[91].


=Mustela erminea salva= Hall

Ermine

Plates 2, 3, 4, 9, 10 and 11

    _Mustela erminea salva_ Hall, Proc. Biol. Soc. Washington, 57:35,
      June 28, 1944; Hall, Journ. Mamm., 26:180, July 19, 1945.

     _Type._--Male, adult, skull only; no. 74641, Mus. Vert. Zoöl.;
     Mole Harbor, Admiralty Island, Alaska, December 27, 1936; obtained
     by A. Hasselborg.

     The skull (plates 2-4) shows malformation of the frontal sinuses
     owing to parasites and lacks osseous tissue where the parasitic
     infestation was localized. The skull is unbroken. The teeth all
     are present and entire.

     _Range._--Admiralty Island, Alaska. See figures 25, 26 on pages
     95, 134.

     _Characters for ready recognition_ (known only from
     skulls).--Differs from males of _M. e. alascensis_ in overall
     depth of braincase which is more than 89 per cent of orbitonasal
     length; from _M. e. initis_, in males, in that orbitonasal length
     and mastoid breadth total less than 35 mm., weight of skull and
     lower jaws less than 2.1 grams; from _M. e. celenda_, in males, in
     that breadth of rostrum measured across lacrimal processes less
     than a third of basilar length.

     _Description._--_Size._--Male: An adult from Gambier Bay measures:
     Total length, 320; length of tail, 95; length of hind foot, 45 (41
     in dry skin).

     Female: A subadult from Hawk Inlet, measures: Total length, 250;
     length of tail, 70; length of hind foot, 33.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that least width of color of underparts in four individuals 40
     (38-43) per cent of greatest width of color of upper parts. Black
     tip of tail, in two individuals for which external measurements
     are given, amounting to 50 and 40 mm. respectively which is 53 and
     57 per cent of length of tail-vertebrae.

     _Skull._--Male (type and 4 adult topotypes): See measurements and
     plates 2-4. As described in _Mustela erminea richardsonii_ except
     that: Weight, 1.7 (1.5-1.9) grams; basilar length, 37.8
     (36.4-39.5, extremes are in subadults); length of tooth-rows more
     or less (usually more) than length of tympanic bulla; interorbital
     breadth rarely more than distance between glenoid fossa and
     posterior border of external auditory meatus.

     Female (2 ad. and 1 ad.-sad. topotypes): See measurements, and
     plates 9-11. As described in _Mustela erminea richardsonii_ except
     that: Weight, 0.9 (0.8-1.0) grams; basilar length, 33.0
     (32.0-33.6); length of tooth rows approximately same as length of
     tympanic bulla; breadth of rostrum approximately 30 per cent of
     basilar length.

From _alascensis_, _salva_ differs in that males have the preorbital
region slightly wider in relation to the length of the tympanic bulla;
also the braincase is smaller, actually as well as in comparison with
the preorbital part of the skull. The tympanic bullae do not project so
far below the squamosals and the braincase itself is shallower, in
adults averaging only 11.5 mm. as against 12.5 mm. The overall depth of
the braincase, including the tympanic bullae, when divided into the
orbitonasal length gives an average of 93 (90-97) per cent whereas in
_alascensis_ the figure is only 85 (78-88) per cent. On this basis
alone, everyone of the adult skulls of the two races can be
distinguished. The females and subadult males show the same tendency to
reduction in depth of braincase but not every individual among them can
be surely distinguished. By weight the skull of _salva_ of
corresponding sex is only about 6 per cent smaller. Comparisons with
_initis_ and _celenda_ are made in the accounts of those subspecies.

_Remarks._--Most of the specimens seen were collected by Allen E.
Hasselborg, resident on Admiralty Island. On the basis of skulls--few
skins, and measurements taken in the flesh, are available--_salva_ more
closely resembles _alascensis_ than does any other subspecies so far
known from southeastern Alaska. The race on Admiralty Island is only
slightly differentiated from _alascensis_ of the adjacent mainland.

     _Specimens examined._--Total number, 26, all from Admiralty
     Island, Alaska, arranged in general by localities from north to
     south, and unless otherwise indicated in the Museum of Vertebrate
     Zoölogy, University of California.

     =Alaska.= Admiralty Island: Hawk Inlet, 2; Seymour Canal, 4; Mole
     Harbor, 18 (skulls only); Gambier Bay, 1; no locality more
     definite than Admiralty Island, 4 (1 in U. S. Nat. Mus.).


=Mustela erminea initis= Hall

Ermine

Plates 4, 5 and 6

    _Mustela erminea initis_ Hall, Proc. Biol. Soc. Washington, 57:37,
      June 28, 1944; Hall, Journ. Mamm., 26:180, July 19, 1945.

     _Type._--Male, adult, skull and skin; no. 289, Mus. Vert. Zoöl.;
     Saook Bay, Baranof Island, Alaska; October 9, 1907; obtained by A.
     Hasselborg, original no. 4.

     The top of the skull is fractured on the left side from the
     anterior nares posteriorly through the postorbital process to the
     posterior root of the zygomatic arch. On the left lower jaw the
     canine and three incisors are missing; otherwise the teeth all are
     present and entire.

     The skin is in process of molt, approximately nine-tenths of the
     incoming white pelage being in place. The skin is well made and in
     a good state of preservation.

     _Range._--Chichagof and Baranof islands, Alaska. See figures 25,
     26 on pages 95, 134.

     _Characters for ready recognition_ (only males known).--Differs
     from _M. e. arctica_, in that proximal two-thirds of under side of
     tail colored same as upper parts rather than same as underparts,
     zygomatic breadth less than distance between last upper molar and
     jugular foramen; from _M. e. salva_ in that orbitonasal length and
     mastoid breadth total more than 35 mm., weight of skull and lower
     jaws more than 2.1 grams; from _M. e. alascensis_, by total length
     more than 317, black tip of tail more than 57 per cent of length
     of tail-vertebrae, interorbital breadth more than 10.3 and equal
     to, instead of less than, distance between glenoid fossa and
     posterior border of external auditory meatus; from _M. e. celenda_
     by chest white (not mostly covered by brown patch), breadth of
     rostrum measured across lacrimal processes less than a third of
     basilar length; from _M. e. seclusa_ in zygomatic breadth more
     than distance between last upper molar and jugular foramen.

     _Description._--_Size._--Male: The type and an adult topotype
     measure, respectively, as follows: Total length, 330, 320; length
     of tail, 95, 95; length of hind foot, 45, 45.

     Female: No external measurements available.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that least width of color of underparts averages, in two young
     female topotypes, 50 (49, 50) per cent of greatest width of color
     of upper parts. Black tip of tail in three young female topotypes
     averaging 54 (52-55) mm. which is 67 (63-69) per cent of length of
     tail-vertebrae.

     _Skull._--Male (illustrated by type and 1 ad. topotype): See
     measurements and plates 4-6. As described in _Mustela erminea
     richardsonii_ except that: Weight, 2.3 and 2.5 grams; basilar
     length, 39.6, and 40.5; interorbital breadth equal to distance
     between glenoid fossa and posterior border of external auditory
     meatus.

     Female: No adults available.

From _salva_, _initis_ differs in that skulls of males average larger
in every measurement taken, being 41 per cent heavier. Relative to the
basilar length, the interorbital and preorbital parts of the skull are
larger; the relatively greater interorbital and mastoid breadths are
particularly noticeable. Although the depth of the braincase, including
the tympanic bullae, is both relatively as well as actually more than
in _salva_, the depth is relatively less than in _alascensis_ which
otherwise differs from initis in about the same way that _salva_
differs from _initis_. Whereas the interorbital breadth in _initis_ is
about equal to the distance between the glenoid fossa and the posterior
border of the external auditory meatus, the interorbital breadth is
uniformly less than this distance in both _salva_ and _alascensis_. In
comparison with _seclusa_ the teeth are of the same size but all
measurements of the skull are larger. The skull of _initis_ is 25 per
cent heavier. In relation to the basilar length, the interorbital and
preorbital parts of the skull are much less in _initis_. The preorbital
and interorbital regions in _initis_ are relatively smaller in
comparison also with _arctica_. The one measurement of interorbital
breadth in _initis_ is greater in relation to the basilar length than
in _kadiacensis_ but the rostral region, and all that part of the skull
anterior to the braincase, is relatively smaller in _initis_.

_Remarks._--The two adult males, nos. 286 and 289 from Saook Bay,
provide convincing evidence of the existence of a distinct race of
weasel on Baranof Island. Three other young specimens, almost subadult,
from the same place are labeled as males although the basilar lengths
of these skulls are only 35.5, 35.9 and 37.3 millimeters as against
39.6 and 40.5 in the two adult males. The difference in size is too
great to be age-variation. The fact that 3 are definitely of one
category and 2 of the other makes it doubtful that individual variation
accounts for the differences. The small size of these 3 specimens and
the fact that in each the anterior margin of the tympanic bulla is
flush with the squamosal rather than protruded from the braincase,
suggests that the three are females. If they are females, the amount of
secondary sexual variation is rather less than would be expected by
analogy with the amount obtaining in _alascensis_ on the mainland and
in _salva_ on Admiralty Island. Another possibility that I can not
disprove is that two stocks of weasels persist on Baranof Island, the
two larger specimens being descendants of the stock which first became
established on the island and the three smaller specimens being
descendants of an individual ermine, or of ermines, that were rafted or
otherwise transported to the island at a considerably later date.
Assuming for the moment that there are two stocks, it must be admitted
that each one differs from any stock known from elsewhere. Therefore,
each stock would be presumed to have been long resident on the island.
But--two stocks as closely related as the two in question would not be
expected to persist for long in an area as small as that of Baranof
Island because competition would give one the ascendancy. Therefore,
the first suggestion, namely that the three smaller animals are really
females, seems the more probable. The feasible way to clear up the
present uncertainty is, of course, to obtain additional specimens,
carefully labeled as to sex. Yet another reason why additional
collecting is desirable in this area is to ascertain whether there is
subspecific differentiation between the ermines of Baranof and
Chichagof islands. The one specimen available from the latter island,
although in general like the three smaller animals from Baranof Island,
differs in the fuller (less scooped out) medial side of the tympanic
bulla and to a slight degree in each of some other features. This
specimen from Chichagof Island is labeled as a male also.

     _Specimens examined._--Total number, 6, arranged by localities
     from north to south, and in the Museum of Vertebrate Zoölogy,
     University of California.

     =Alaska.= Chichagof Island, Freshwater Bay, 1. Baranof Island,
     Saook Bay, 5.


=Mustela erminea celenda= Hall

Ermine

Plates 5, 6 and 7

    _Mustela erminea celenda_ Hall, Proc. Biol. Soc. Washington, 57:38,
      June 28, 1944; Hall, Journ. Mamm., 26:181, July 19, 1945.

     _Type._--Male, adult, skull and skin; no. 130987, U. S. Nat. Mus.,
     Biol. Surv. Coll.; Kasaan Bay, Prince of Wales Island, Alaska;
     June 16, 1903; obtained by Cyrus Catt; original no. 4407X.

     The skull has a piece 1.5 mm. long broken out of the left
     zygomatic arch. P2 is absent on both sides. The right I1, and the
     left I1 and I2 are missing. The skin, in summer pelage, is fairly
     well made. A scrotal pouch attests to the correctness of the sex
     recorded on the label. The rostral part of the skull is smaller
     than in average-sized males of corresponding age.

     _Range._--Prince of Wales, Dall, and Long islands, Alaska. See
     figures 25, 26 on pages 95, 134.

     _Characters for ready recognition_ (only males known).--Differs
     from _M. e. alascensis_ and _initis_ in chest mostly covered by
     brown patch, not white, and breadth of rostrum measured across
     lacrimal processes more than a third of basilar length, which
     cranial character serves to distinguish also _salva_; from _M. e.
     seclusa_ in zygomatic breadth less than distance between last
     upper molar and jugular foramen; from _M. e. haidarum_ in chest
     white (not mostly covered by brown patch), proximal two-thirds of
     underside of tail colored like upper parts rather than underparts,
     basilar length more than 38.2 mm.

     _Description._--_Size._--Male: Seven adults and subadults from
     Prince of Wales Island, yield average and extreme measurements as
     follows: Total length, 286 (277-304); length of tail, 77 (74-85);
     length of hind foot, 36 (35.5-40.5).

     Female: No specimen available.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that upper parts about tone 3 of dark Chocolate Brown of Oberthür
     and Dauthenay, pl. 342; lower throat and chest covered by a large
     patch of same color as upper parts; color of underparts extending
     to toes but in interrupted fashion on both fore-and hind-feet;
     least width of color of underparts averaging, in four males from
     Prince of Wales Island, 41 (38-49) per cent of greatest width of
     color of upper parts. Black tip of tail averaging, in 8 males in
     winter pelage, 65 (59-78) mm. which is 84 (69-92) per cent of
     length of tail-vertebrae.

     From its geographic neighbors _alascensis_ and _initis_, _celenda_
     differs in darker color of upper parts, presence rather than
     absence of patch of dark color on lower throat and chest, and
     longer black tip on tail. From _haidarum_, _celenda_ differs in
     darker color of upper parts, presence rather than absence of
     patch of dark color on lower throat and chest, narrower
     light-colored under parts, black tip of tail averaging less rather
     than more than nine-tenths of length of tail-vertebrae and ventral
     face of tail colored like upper parts rather than like underparts.

     _Skull._--Male (illustrated by 5 adults): See measurements and
     plates 5-7. As described in _Mustela erminea richardsonii_ except
     that: Weight, 2.3 (2.2-2.5) grams; basilar length, 39.5
     (38.9-40.7) mm.; length of tooth-rows more than length of tympanic
     bulla; breadth of rostrum measured across lacrimal processes more
     than a third of basilar length; interorbital breadth more than
     distance between glenoid fossa and posterior border of external
     auditory meatus; zygomatic breadth more or less than (about equal
     to) distance between last upper molar and jugular foramen.

     Female.--Complete skull of adult unavailable.

Differences from _richardsonii_ are indicated in the formal description
just given. Additional to differences therein noted, _celenda_ differs
from _initis_ in larger interorbital and preorbital parts of the skull
although dimensions of other parts of the skull and the teeth are about
the same or even less. From _salva_, _celenda_ differs in larger
average size in every measurement taken, except for the inner moiety of
M1 which is about the same. The skull of _celenda_ is 35 per cent
heavier. In relation to the basilar length the skull of _celenda_ is
wider, especially in the interorbital and preorbital regions. In
comparison with _alascensis_ the tympanic bullae are of approximately
the same length; otherwise essentially the same differences obtain as
are noted in comparison with _salva_ and the zygomatic breadth is
relatively more in _celenda_. From _seclusa_, in which the teeth are of
comparable size, _celenda_ differs in that every cranial measurement is
more and the skull is 28 per cent heavier. Because the skull of
_celenda_ is so much longer, its dimensions in other planes are less in
relation to the length than in _seclusa_. _M. e. celenda_ is larger in
every part measured than _haidarum_, 21 per cent heavier, and in
relation to the basilar length the interorbital, and preorbital, parts
of the skull are smaller, the braincase is shallower, and the skull is
relatively wider across the zygomata and mastoid processes. In
comparison with _kadiacensis_, differences are: 26 per cent lighter,
skull shorter; in relation to the basilar length, braincase shallower
as measured at the anterior end of the basioccipital, tooth-rows
shorter but orbitonasal length more. In comparison with _arctica_ all
parts measured of the teeth and skull of _celenda_ are smaller and its
skull is 34 per cent lighter. In relation to the basilar length, the
interorbital breadth of _celenda_ is only slightly less but its skull
is narrower across the rostrum and zygomata, the tooth-rows are
shorter, and the braincase is shallower.

_Remarks._--The late George Willett in the course of his work in Alaska
collected most of the known specimens of this strongly differentiated
subspecies. In both coloration and cranial characters the
distinguishing features are so well marked that the zoölogist could
with reason accord full specific rank to _celenda_. Nevertheless it
obviously is an ermine. Also, races from other islands of southeastern
Alaska tend to bridge the gap, as regards cranial features, between
_celenda_ and the mainland ermine. The specimen from Dall Island agrees
in all respects with topotypes. The specimen from Howkan on Long Island
is in white winter pelage and the skull has suffered shrinkage from
some chemical solution; the reference of this specimen to _celenda_ is
tentative.

     _Specimens examined._--Total number, 25, as follows: Arranged by
     localities from north to south. Unless otherwise indicated, in U.
     S. National Museum.

     =Alaska.= Prince of Wales Island: Craig, 18 (10 in Mus. Vert.
     Zoöl., and 8 in Los Angeles Mus. Hist. Art and Sci.); Kasaan Bay,
     2; no locality more definite than the Island itself, 3; Dall
     Island, Otter Harbor, 1 (Los Angeles Mus. Hist. Art and Sci.).
     Long Island, Howkan, 1 (Field Mus. Nat. Hist.).


=Mustela erminea seclusa= Hall

Ermine

Plates 5, 6 and 7

    _Mustela erminea seclusa_ Hall, Proc. Biol. Soc. Washington, 57:39,
      June 28, 1944; Hall, Journ. Mamm., 26:181, July 19, 1945.

     _Type._--Male, adult, skull alone; no. 31232, Mus. Vert. Zoöl.;
     Port Santa Cruz, Suemez Island, Alaska; March 24, 1920; obtained
     by George Willett.

     The skull (plates 5-7) is complete and unbroken. Of the upper
     incisors only right I3 is present. Otherwise the teeth are present
     and unbroken.

     _Range._--Known only from the type locality. See figures 25, 26 on
     pages 95, 134.

     _Characters for ready recognition_ (only the male known).--Differs
     from _M. e. celenda_ in basilar length less than 38.2, from _M. e.
     salva_, _initis_ and _haidarum_ in zygomatic breadth more than
     distance between last upper molar and jugular foramen.

     _Description.--Size_ and _Color._--No external measurements or
     skins available.

     Skull.--Male: See measurements and plates 5-7. As described in
     _Mustela erminea richardsonii_ except that: Weight, 1.8 grams;
     basilar length, 34.3; length of tooth-rows about the same as
     length of tympanic bulla; breadth of rostrum measured across
     lacrimal processes more than a third of basilar length;
     interorbital breadth more than distance between glenoid fossa and
     posterior margin of external auditory meatus; zygomatic breadth
     more than distance between last upper molar and jugular foramen.

     Female.--Skull not available.

From _alascensis_ and _salva_, _seclusa_ differs in larger teeth,
shorter skull, much larger preorbital and interorbital regions,
actually as well as in relation to basilar length. Excepting the teeth,
which are of about the same size, the same general differences obtain
in comparison with _initis_ which, however, is 29 per cent heavier.

From _celenda_, _seclusa_ differs in smaller skull in all parts
measured, being 22 per cent lighter. The teeth are about the same size.
In relation to its length the skull of _seclusa_ is much broader and
deeper. From _haidarum_, _seclusa_ differs in: teeth larger; skull
shorter and more convex in dorsal outline along median longitudinal
axis; in relation to basilar length, skull broader, deeper and
braincase relatively shorter.

_Remarks._--The characters shown in the one available skull are far
outside the limits of individual variation for other known subspecies.
Other specimens are much to be desired to ascertain what the "average"
individual is like and to learn the characters of the female.

     _Specimen examined._--One, the holotype.


=Mustela erminea haidarum= (Preble)

Ermine

Plates 5, 6, 7, 11, 12 and 13

    _Putorius haidarum_ Preble, Proc. Biol. Soc. Washington, 12:169,
      August 10, 1898.

    _Mustela haidarum_, Miller, U. S. Nat. Mus. Bull., 79:97, December
      31, 1912.

    _Mustela erminea haidarum_, Hall, Proc. Biol. Soc. Washington,
      57:38, June 28, 1944; Hall, Journ. Mamm., 26:181, July 19, 1945.

     _Type._--Male, adult, skull, skeleton and skin; no. 94430, U. S.
     Nat. Mus., Biol. Surv. Coll.; Massett, Queen Charlotte Islands,
     British Columbia; March 17, 1898; obtained by J. H. Keen; original
     no. 1800x.

     The skull is unbroken and complete except for osseous tissue
     destroyed in the region of each postorbital process; this is the
     result of infestation of the frontal sinuses by parasites. The
     skeleton is complete down to the distal ends of the tibiae; the
     more distal bones are in the skin. The first, right, upper incisor
     is missing. Otherwise the teeth all are present and entire.

     The skin is in the white, winter pelage but the new under fur is
     visible along the back and on the head although mostly covered
     with white hair.

     _Range._--Queen Charlotte Islands. See figure 25, page 95.

     _Characters for ready recognition._--Differs from _M. e. celenda_
     in chest white (not mostly covered by brown patch), proximal
     two-thirds of under side of tail colored like underparts instead
     of upper parts, in males basilar length less than 38.2; from _M.
     e. seclusa_, in male, in zygomatic breadth less than distance
     between last upper molar and jugular foramen; from _M. e.
     richardsonii_ and _alascensis_, in both sexes, in proximal
     two-thirds of under side of tail colored like underparts instead
     of upper parts, interorbital breadth not less than distance from
     glenoid fossa to posterior margin of external auditory meatus;
     from _M. e. anguinae_ and _fallenda_, in both sexes, in
     light-colored underparts more than half the width of dark-colored
     upper parts, proximal two-thirds of under surface of tail colored
     like underparts instead of upper parts, interorbital breadth equal
     to or more than distance between glenoid fossa and posterior
     margin of external auditory meatus.

     _Description.--Size._--Male: Two adults, U.S.N.M., no. 100622,
     from Cumsheva Inlet, and Amer. Mus. N. H., no. 37411, and the
     type, measure, respectively, as follows: Total length, 283, 290,
     275; length of tail, 70, 75, 60; length of hind foot, 39, 40, 37.

     Female: Corresponding measurements of an adult, no. 100624, and a
     young individual, no. 100623, each from Cumsheva Inlet, are: 252,
     250; 63, 61; 31, 32.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that underparts not Sulphur Yellow but ranging from near (_e_)
     Colonial Buff through Marguerite Yellow to almost pure white;
     color of underparts extends distally on posterior sides of
     forelegs and onto toes but in many specimens interrupted at wrist
     by color of upper parts; color of underparts extends onto proximal
     three-fourths of under side of tail as length of tail is measured
     along tail-vertebrae; least width of color of underparts
     averaging, in 5 males, 79 (66-130) per cent of greatest width of
     color of upper parts. Black tip of tail in same males averaging 62
     (60-70) mm. which is 92 (83-115) per cent of length of
     tail-vertebrae.

     The close correspondence in color-pattern of this weasel with the
     Arctic races, _arctica_, _polaris_, _semplei_ and _kadiacensis_ is
     noteworthy, and distinguishes it from weasels on the adjacent
     mainland and adjoining islands to the north and south. The color
     of the upper parts is darker than in the four Arctic races named.

     _Skull._--Male (7 adults): See measurements and plates 5-7. As
     described in _Mustela erminea richardsonii_ except that: Weight,
     1.9 (1.7-2.0) grams; basilar length, 36.7 (35.6-37.5); length of
     tooth-rows more than length of tympanic bullae; breadth of rostrum
     measured across lacrimal processes more than a third of basilar
     length; interorbital breadth more than distance between glenoid
     fossa and posterior margin of external auditory meatus; zygomatic
     breadth barely less than distance between last upper molar and
     jugular foramen.

     Female (2 adults): See measurements and plates 11-13. As described
     in _Mustela erminea richardsonii_ except that: Weight, 1.3 and 1.4
     grams; basilar length, 34.2; length of tooth-rows more or less
     than (about equal to) length of tympanic bulla; breadth of rostrum
     more than 30 per cent of basilar length; interorbital breadth not
     less than distance between glenoid fossa and posterior margin of
     external auditory meatus.

From _richardsonii_, _haidarum_ differs in that skull of the male is
actually larger in its anterior part (breadth of rostrum, interorbital
breadth and orbitonasal length) but all measurements of other parts
average less. In relation to the basilar length, the tympanic bulla is
shorter but all other measurements are more. In the skull of the
female, which is 23 per cent heavier, the width of the tympanic bulla
and anteroposterior extent of the inner lobe of M1 are the same; in all
other measurements the female of _haidarum_ is larger, and in relation
to the basilar length all measurements are more except the depth of the
skull at the anterior margin of the basioccipital and the width of the
tympanic bulla, which are less. By actual weight the skull of the male
is 25 per cent lighter and the skull of the female 24 per cent heavier
than in _richardsonii_. From _fallenda_ and _anguinae_, _haidarum_
differs in that measurements of the skulls of both sexes either average
more, or are uniformly more, with two exceptions. These are the lesser
length and breadth of the tympanic bulla, in comparison with males of
_fallenda_, and the dimensions of M1 which are about the same in all
three races concerned. The pre-and interorbital parts are larger in
relation to the remainder of the skull. The postorbital breadth is
actually a third more than in _fallenda_. In relation to the basilar
length, the tympanic bulla is shorter and the braincase deeper than in
males of _anguinae_. The skull of the male is 27 per cent heavier than
that of _fallenda_ and 58 per cent heavier than that of _anguinae_. The
skull of the female is 59 and 50 per cent heavier than those of
_fallenda_ and _anguinae_, respectively. Comparison of the skull with
those of _alascensis_, _celenda_ and _seclusa_ has been made in the
accounts of those subspecies.

_Remarks._--The available specimens of this ermine were obtained by J.
H. Keen in 1898, Wilfred H. Osgood and E. A. Lewis in 1900, W. W. Brown
in 1914, J. A. Munro in 1917 and 1918, and Allan Brooks in 1920. _M. e.
haidarum_ has more claim to full specific status than any other race of
ermine because the diagnostic structural features are numerous and
individually of relatively great degree. Indeed, individual variation
appears not to bridge the gap between any population of _haidarum_ and
other subspecies and strong reasons could be advanced for according
_haidarum_ the status of a full species. It differs from the subspecies
of _erminea_ on the adjoining mainland and adjoining islands to the
north and south and agrees with the Arctic races (_arctica_, _polaris_,
_semplei_ and _kadiacensis_) in great extent of the color of the
underparts, extension of this color onto the underneath side of the
tail, long black tip of the tail and general form of the skull
including the relatively heavy preorbital region. The color although
darker than in the Arctic subspecies, is lighter than in the insular
races immediately to the north and south. In combination, the features
mentioned could be taken as indication that _haidarum_ is a relict
population from a former glacial period. Assuming that it is a relict
population, the color may have become slightly darker since that period
but the main response appears to have been a decrease in size for this
is a much smaller animal than the Arctic ermines. The size is about
what would be expected if one were to judge by the slightly larger
ermines on the islands of southeastern Alaska to the north and the
smaller ermine on Vancouver Island to the south.

The ermines of the islands of southeastern Alaska, excepting possibly
the incompletely known _seclusa_, have fewer characters of the Arctic
races and more characters of the races of the adjoining mainland.
Therefore, a possible inference is that the distinctive characters of
ermines of the Alaskan islands developed with the aid of isolation from
stocks which reached the islands after the glacial period. _M. e.
haidarum_ may have found its way to the Queen Charlotte Islands in the
glacial period.

     _Specimens examined._--Total number, 17, as follows. Arranged by
     locality from north to south. Unless otherwise indicated,
     specimens are in the U. S. National Museum.

     =British Columbia.= Queen Charlotte Islands. Masset, 7 (4[74],
     1[2], 1[59]); Skidegate, 1; Graham Island, 5 (2[94], 1[77], 1[2]);
     Cumsheva Inlet, 3; no locality more definite than Queen Charlotte
     Islands, 1[2].


=Mustela erminea anguinae= Hall

Ermine

Plates 5, 6, 7, 11, 12 and 13

    _Mustela cicognanii anguinae_ Hall, Univ. California Publ. Zoöl.,
      38:417, November 8, 1932.

    _Putorius cicognanii_, Baird, Mamm. N. Amer., p. 161, 1858 (part).

    _Putorius streatori_, Swarth, Univ. California Publ. Zoöl., 10:102,
      February 13, 1912.

    _Mustela erminea anguinae_ Hall, Journ. Mamm., 26:79, February 27,
      1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

     _Type._--Male, adult, complete skeleton (no skin); no. 12482, Mus.
     Vert. Zoöl., French Creek, Vancouver Island, British Columbia;
     found as a desiccated carcass on May 1, 1910; obtained by Harry S.
     Swarth.

     _Range._--Vancouver Island, British Columbia. See figures 25, 27
     pages 95, 149.

     _Characters for ready recognition._--Differs from _M. e.
     haidarum_, in both sexes, in light-colored underparts less than
     half the width of dark-colored upper parts, proximal two-thirds of
     under surface of tail colored like upper parts instead of
     underparts, interorbital breadth less than distance between
     glenoid fossa and posterior margin of external auditory meatus;
     from _M. e. fallenda_, in both sexes, anterior margin of tympanic
     bullae flush with squamosal rather than projecting from floor of
     braincase, in males by sagittal crest absent, in females by total
     length more than 238 and tooth-rows about same length as, instead
     of longer than, tympanic bulla; from _M. e. streatori_, in male,
     by sagittal crest absent and hind foot ordinarily more than 33.5,
     in female by hind foot more than 27.5, basilar length more than
     30.2; from _M. e. olympica_, in males, by greater average size,
     hind foot ordinarily more than 33.4 and interorbital breadth
     ordinarily more than 8.5, in females by larger size, total length
     more than 235, tail more than 65, hind foot more than 27.5,
     basilar length more than 30.2.

     _Description._--_Size._--Male: Sixteen adults and subadults yield
     average and extreme measurements as follows: Total length, 272
     (261-284) mm.; length of tail, 81 (74-86); length of hind foot,
     35.0 (33.5-36).

     Female: Five adults and subadults have corresponding measurements
     as follows: 247 (241-257); 69 (66-73); 30.0 (28.0-32.0).

     _Color._--As described in _Mustela erminea streatori_ except that:
     occasionally white in winter; upper parts about tone 2 of Dark
     Chocolate of Oberthür and Dauthenay; least width of color of
     underparts averaging, in 7 adult males, 6 (0-15) per cent of
     greatest width of color of upper parts. Black tip of tail in same
     series averaging 37 (26-46) mm. which is 46 (32-54) per cent of
     length of tail-vertebrae.

     _Skull._--Male (based on 13 adults): See measurements and plates
     5-7. As described in _Mustela erminea richardsonii_ except that:
     Weight, 1.2 (1.0-1.3) grams; basilar length, 34.0 (32.5-35.6);
     length of tooth-rows more or less (usually less) than length of
     tympanic bulla.

     Female (based on 5 adults): See measurements and plates 11-13. As
     described in _Mustela erminea richardsonii_ except that: Weight
     0.9 (0.77-1.06) grams; basilar length, 31.5 (30.9-31.8) grams;
     length of tooth-rows more or less than (approximately same as)
     length of tympanic bulla; breadth of rostrum more than 30 per cent
     of basilar length.

The sexual dimorphism in the skull is slight, the skull of the male
being only a third heavier than that of the female. In _fallenda_ of
the adjacent mainland to the east the male is three-fourths heavier
than the female. In comparison with _fallenda_, males are smaller,
averaging less in every cranial and dental measurement taken and by
weight are a fifth lighter; sagittal crest absent rather than present;
tympanic bullae flush with squamosal rather than projecting below floor
of braincase; in relation to basilar length, tympanic bullae smaller,
braincase deeper and broader, skull wider interorbitally and across
zygomata. Females are larger than in _fallenda_, and with one exception
average larger in every cranial and dental measurement taken, being 6
per cent heavier. The one exception mentioned is the lesser actual
length of the tympanic bulla in _anguinae_, in which the length of the
tooth-rows is about the same as, rather than less than, the length of
the tympanic bulla. The postorbital breadth is greater than in
_fallenda_ and the anterior edges of the tympanic bullae are flush with
the squamosals rather than projecting below the floor of braincase. In
relation to the skull as a whole the preorbital and interorbital parts
are larger.

In comparison with _streatori_, skulls of males are of about the same
size, _anguinae_ being only 9 per cent heavier. The length of the
tooth-rows is ordinarily less than, rather than about equal to, the
length of the tympanic bulla; sagittal crest wanting rather than
present since in _anguinae_ the temporal muscles meet usually only at
the posterior end of the braincase instead of all along the midline on
its top; tympanic bullae narrower and more nearly flush with squamosal
(less protruded from braincase). Relative to the basilar length, the
zygomatic breadth is more, the tympanic bullae are narrower, and the
braincase is deeper at the anterior end of the basioccipital. The
female is 41 per cent heavier than _streatori_, there being no overlap
in most cranial and dental measurements. M1, however, is approximately
the same size in each subspecies. The tooth-rows and tympanic bulla are
of almost equal length whereas in _streatori_ the length of the
tooth-rows is less than that of the bulla.

Differences from _olympica_, in males, are: M1 shorter; all other
measurements of teeth and parts of skull averaging larger; skull 20 per
cent heavier; tooth-rows averaging shorter than tympanic bulla rather
than about the same; relative to basilar length, braincase deeper at
anterior end of basioccipital and tooth-rows shorter. The skull of the
female is 64 per cent heavier, larger in every measurement taken
without overlap; temporal ridges meeting, rather than separated, at
lambdoidal crest; length of tooth-rows about equal to, rather than
shorter than, tympanic bulla; in relation to basilar length, skull
deeper, orbitonasal length more, mastoid and zygomatic breadths more,
and tympanic bullae shorter.

_Remarks._--References in the literature to this insular race mostly
were under the name _streatori_ until 1932 when in the course of the
present study the name _anguinae_ was proposed. A few specimens have
been taken by nearly every student of small mammals who has collected
on Vancouver Island. Arthur Peake and Herbert Laing have probably
collected more specimens than any other two zoölogists.

_M. c. anguinae_ is noteworthy for the slight secondary sexual
variation in size; the disparity between the two sexes is less than in
any other American subspecies of _erminea_. By linear measurement the
body of the female is only 7 per cent shorter than in the male (178
versus 191 mm.). Linear measurements and weights of the skulls of the
two sexes are further indicative of this approximation in size. By
weight the skull of the female is only a fourth lighter than that of
the male, or, stated in another way, the male's skull is only a third
heavier (1.2 versus 0.9 grams).

No geographic variation has been detected between lots of specimens
from different parts of Vancouver Island. The one specimen available
from Salt Spring Island presents no obvious differences from selected
individuals from Vancouver Island.

The winter pelage is more often brown than white. Of 17 specimens seen
in winter pelage or in transition pelage, only 6 are white. These 6 are
from Comox, Stamp River, Hilliers, Jeune Landing and Port Alice. Of the
34 specimens in brown pelage, 7 have the dark color of the upper parts
meeting on the abdomen. Six of the 34 have brown color on the pectoral
region. In two, this is a separate patch but in the other four the dark
color is a continuation of the upper parts and extends in front of each
foreleg over part of the pectoral region, but the two extensions, one
from either side, do not meet on the underparts. The color of the lips
was recorded in 22 individuals: one had both the upper and lower-lips
white; 7 had the upper lips brown and the lower lips white; in 14 both
the upper and lower-lips were brown.

     _Specimens examined._--Total number, 40, listed by localities from
     north to south as follows. Unless otherwise indicated, specimens
     are in the National Museum of Canada.

     =British Columbia.= Vancouver Island: Cape Scott, 4; Shushartie,
     1; Quatsino, 1[74]; Jeune Landing, 1[74]; Port Alice, 5[15];
     Marble Creek, Quatsino Sound, 1[22]; Port Hardy, 5; Sayward, 2;
     Bear Lake, 4; Bear River, 1; Comox, 4(3[85]); Stamp River,
     Alberni, 1[31]; Errington, 1[74]; French Creek, 1[74]; Hilliers,
     1[74]; Craigs Crossing, 1[74]; Nanaimo, 2[22]; Cowichan Lake,
     1[22]; Duncan, 2[85]; Salt Spring Island, 1[85].


=Mustela erminea fallenda= Hall

Ermine

Plates 5, 6, 7, 11, 12 and 13

    _Mustela erminea fallenda_ Hall, Journ. Mamm., 26:79, February 27,
      1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

    _Putorius streatori_ Merriam, N. Amer. Fauna, 11:13, June 30, 1896
      (part-Sumas).

[Illustration: FIG. 27. Map showing known occurrences and probable
geographic ranges of the subspecies of _Mustela erminea_ in Washington
and parts of British Columbia and Oregon.]

     _Type._--Male, adult, skull and skin; no. 7096, Nat. Mus. Canada;
     Huntingdon, British Columbia; May 21, 1927; obtained by C. H.
     Young, original no. 317.

     The brown summer skin is well made. The skull (plates 5-7) is
     complete. Right p2 has the crown broken away; otherwise the teeth
     all are present and entire.

     _Range._--On mainland in immediate vicinity of coast from probably
     opposite Texada Island, British Columbia, south to Lake Whatcom,
     Washington, and east to Mount Baker Range on International
     boundary. See figures 25, 27 on pages 95, 149.

     _Characters for ready recognition._--Differs from _M. e.
     haidarum_, in both sexes, in light-colored underparts less than
     half the width of dark-colored upper parts, proximal two-thirds of
     under surface of tail colored like upper parts instead of
     underparts, interorbital breadth less than distance between
     glenoid fossa and posterior margin of external auditory meatus;
     from _M. e. richardsonii_ in both sexes, by upper lips brown
     rather than white, in males hind foot less than 41 and basilar
     length less than 38.3, in females hind foot less than 29, basilar
     length less than 31.4 and breadth of rostrum more, instead of
     less, than 30 per cent of basilar length; from _M. e. invicta_, in
     both sexes, by upper lips brown (not white); in males by skull
     averaging shorter (basilar length 35.7 versus 37.0); in females by
     breadth of rostrum more, instead of less, than 30 per cent of
     basilar length; from _M. e. anguinae_, in both sexes, by anterior
     margin of tympanic bulla projecting from floor of braincase rather
     than flush with squamosal (the difference is slight in females),
     in males by sagittal crest present, in females by total length
     less than 238 and tooth-rows longer than, instead of about same
     length as, tympanic bulla; from _M. e. streatori_, in both sexes,
     by black tip of tail more than half of length of tail-vertebrae,
     in males hind foot more than 33.7, tympanic bulla longer than,
     instead of about same length as, upper tooth-rows; weight of skull
     more than 1-1/4 grams, in females weight of skull more than 0.7
     grams, length of lateral side of P4, 4 mm. or more; from _M. e.
     olympica_, in males, length of hind foot more than 33, black tip
     of tail more than 36.5 mm., weight of skull more than 1.2 grams,
     basilar length more than 33.5, in females length of hind foot more
     than 25.5, weight of skull more than 0.66 grams, basilar length
     more than 28.4; from _M. e. gulosa_, in both sexes, by anterior
     margin of tympanic bulla projecting below floor of braincase
     rather than flush with squamosal (the difference is slight in
     females), in males hind foot more than 33.5, weight of skull more
     than 1-1/4 grams, basilar length more than 33.9, in females by
     total length more than 222, hind foot longer than 26, weight of
     skull more than 0.7 grams, basilar length more than 29.

     _Description.--Size._--Male: Seven adult topotypes yield average
     and extreme measurements as follows: Total length, 278 (249-305);
     length of tail, 77 (69-81); length of hind foot, 36.5 (34-40). A
     male topotype of unknown age weighed 113 grams.

     Female: Two adult topotypes, with actual measurements in
     parentheses, average as follows: Total length, 232 (228-236);
     length of tail, 60 (57-62); length of hind foot, 27 (27-27). An
     adult from Morovitz Guard Station, Wash., weighed 54 grams.

     _Color._--Winter pelage rarely white, brown pelage
     indistinguishable from summer pelage except for slightly more
     smoky tinge in winter in specimens from some localities; otherwise
     as described in _Mustela erminea streatori_ except that least
     width of color of underparts averaging, in seven adult topotypes,
     18 (0-37) per cent of greatest width of color of upper parts.
     Black tip of tail averaging, in same series, 45 (38-52) mm. which
     is 58 (53-65) per cent of length of tail-vertebrae.

     In comparison with _richardsonii_ and _invicta_, _fallenda_
     differs in darker color of upper parts and their extension at the
     expense of the light-colored underparts which are narrower by a
     half. In correlation with this restriction in area of the
     light-colored underparts, the upper lips are brown instead of
     white. In comparison with _anguinae_, _olympica_ and _streatori_,
     the longer black tip on the tail is the principal difference in
     color. From _gulosa_, _fallenda_ differs in slightly darker color
     of upper parts and in narrow underparts, the width of the same
     being only about a fifth instead of a third of the width of the
     dark-colored upper parts.

     _Skull._--Male (based on 7 adults): See measurements and plates
     5-7. As described in _Mustela erminea richardsonii_ except that:
     Weight, 1.5 (1.3-1.7) grams; basilar length, 35.7 (34.3-38.2).

     Female (based on 6 ads.): See measurements and plates 11-13. As
     described in _Mustela erminea richardsonii_ except that: Weight,
     0.85 (0.73-1.0) grams; basilar length, 30.6 (29.4-31.7); breadth
     of rostrum more than 30 per cent of basilar length.

In comparison with _richardsonii_, skulls of males differ as follows:
averaging smaller in every measurement taken with no overlap in several
dimensions; 40 per cent lighter; in relation to basilar length, rostrum
(orbitonasal length) longer and skull slightly broader interorbitally.
Females average smaller in every cranial and dental measurement taken
with no overlap in basilar length, length of tooth-rows and length of
tympanic bulla; 22 per cent lighter; breadth of rostrum more, rather
than less, than 30 per cent of basilar length; in relation to basilar
length, pre-and interorbital parts of skull larger, and mastoid breadth
more.

Differences from males of _olympica_ are: size larger with no overlap
in most measurements; 50 per cent heavier; tympanic bullae longer than
upper tooth-rows rather than of about equal length; in relation to
basilar length, rostrum shorter, braincase wider and deeper, zygomata
more expanded. Females are larger with no overlap in most measurements;
35 per cent heavier; in relation to basilar length, pre-and
interorbital regions narrower, braincase deeper and wider across
mastoids.

Differences from _streatori_, in males, are: skull averaging larger in
every cranial and dental measurement taken; 36 per cent heavier;
tympanic bulla longer than, instead of about same length as,
upper tooth-rows. In females the inner lobe of M1 is shorter
anteroposteriorly; otherwise all measurements of _fallenda_ average
larger and it is 33 per cent heavier; rostrum and interorbital region
broader in relation to remainder of skull.

In comparison with _gulosa_, skulls of males differ as follows:
averaging larger in every measurement taken with no overlap in several
dimensions; 50 per cent heavier; tympanic bullae with anterior margins
projecting slightly below squamosals rather than flush with same;
length of bulla more than, rather than about same as, that of upper
tooth-rows. Considering the great difference in size, the relative
proportions are remarkably alike. In females, length of inner lobe of
M1 about the same; otherwise averaging larger in every measurement
taken; 44 per cent lighter; relative to basilar length, tooth-rows
longer, skull wider across zygomata and mastoids, rostrum and
interorbital regions slightly narrower, skull shallower in plane of
last upper molars.

Comparisons with _haidarum_, _invicta_ and _anguinae_ are made in
accounts of those subspecies.

_Remarks._--Until the name _fallenda_ was proposed in the course of the
present study, most of the specimens of this race were assigned to
_streatori_.

Intergradation with _streatori_ is complete as it is also with
_invicta_ and _richardsonii_, in other words with each of the
subspecies whose ranges meet that of _fallenda_. In color and in size
the difference is least between _streatori_ and _fallenda_. As between
_fallenda_ and _invicta_ the size is not greatly different and the
intergradation in color is gradual. Between _fallenda_ and
_richardsonii_ intergradation is somewhat different and to fully
appreciate its nature we should remember that the color of _fallenda_
resembles that of the saturate coastal races, _streatori_, _anguinae_
and _olympica_ although the black tip of the tail is longer. In this
latter feature and in several cranial details, as well as in greater
degree of secondary sexual variation in size, _fallenda_ resembles
_richardsonii_. Because the two differ more than do most subspecies of
ermine whose ranges meet, some of the intergrades at first inspection
appear to be widely different from either parent stock. For example,
specimens from Alta Lake, British Columbia, may give this impression
because the combination of large size and dark color suggests a kind of
ermine different from either _fallenda_ or _richardsonii_. In no
instance, however, has there been found in these intergrades any
character other than those occurring in one or the other of the two
parent races.

Along the coast in the north part of the geographic range assigned to
_fallenda_, some specimens nearly typical of _richardsonii_ have been
taken so near to the place where fairly typical _fallenda_ was
obtained that I have doubted whether there is intergradation in the
usual fashion in this area; more specimens will have to be obtained
from this coastal area to resolve the doubt one way or the other.

The winter pelage is brown in all specimens at most localities. The
only white pelage seen was in each of three specimens from Glacier,
Whatcom County, Washington. A fourth specimen from there is in brown
winter pelage. At any one locality there is much variation in the
degree to which the dark color of the upper parts encroaches on the
area that in most other races is light-colored. An extreme degree of
encroachment is shown by a specimen taken on December 1, 1935, by R. A.
Cummings, at Vancouver, British Columbia, in which the light color
occurs only in three restricted areas, the chin, the throat and the
lower breast; otherwise the coat is brown. There are other specimens,
for instance from the type locality, which differ mainly in having an
additional white spot in the inguinal region. The opposite extreme, in
a specimen also from the type locality, is where the least width of the
light-colored underparts on the abdominal region is a third of the
circumference of the body. The two extremes are connected by a dozen
intermediate stages. Of 64 specimens in which the color of the lips was
carefully examined, one, from Vancouver, has both the upper and
lower-lips brown; 9 have both the upper and lower-lips white; and 54
have the upper lips brown and the lower lips white.

     _Specimens examined._--Total number, 72, arranged by localities
     from north to south. Unless otherwise indicated, specimens are in
     the National Museum of Canada.

     =British Columbia.= Horseshoe Lake, Stillwater, 2; Vancouver,
     1[74]; Point Grey, 1[31]; Port Moody, 5[91]; Chilliwack, 8 (2[75],
     4[91], 1[60]); Sumas, 19 (18[75], 1[60]); Thurstons Ranch, 2;
     Cultus Lake, 2; Mt. Baker Range, 5[75]; Lihumption Park, 1;
     Huntingdon, 14; Tami Hy Creek, 1.

     =Washington.= _Whatcom County_: Semiahmoo, 1[91]; New Whatcom,
     1[68]; Lake Whatcom, 2[91]; 5 mi. W Glacier, 1[51]; Glacier (3 at
     900 ft.), 4[91]; E Side Easton Glacier, Mt. Baker, 1[55]; Morovitz
     Guard Station, 831 ft., 1[55].


=Mustela erminea olympica= Hall

Ermine

Plates 5, 6, 7, 12, 13 and 14

    _Mustela erminea olympica_ Hall, Journ. Mamm., 26:81, February 27,
      1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

    _Mustela rixosa_, Svihla and Svihla, Murrelet, 13:24, January,
      1932.

    _Mustela rixosa rixosa_, Svihla and Svihla, Murrelet, 14:39, May,
      1933.

     _Type._--Male, adult, skull and skin; no. 90738, U. S. Nat. Mus.,
     Biol. Surv. Coll.; near head of Soleduc River, 4500 ft., Olympic
     Mountains, Clallam County, Washington; April 28, 1897; obtained by
     Vernon Bailey, original no. 6213.

     The skin is well prepared and in good condition. The skull (plates
     5-7) is unbroken and the teeth all are present and entire.

     _Range._--Olympic Peninsula, Washington, south to Olympia. See
     figures 25, 27 on pages 95, 149.

     _Characters for ready recognition._--Differs from _M. e.
     anguinae_, in males, by lesser average size, hind foot ordinarily
     less than 33.4, and interorbital breadth ordinarily less than 8.5,
     in females by smaller size, total length less than 235, tail less
     than 65, hind foot less than 27.5, basilar length less than 30.2;
     from _M. e. fallenda_, in males, by length of hind foot less than
     33, black tip of tail less than 36.5, weight of skull less than
     1.2 grams, basilar length less than 33.5, in females length of
     hind foot less than 25.5, weight of skull less than 0.6 grams,
     basilar length less than 28.4; from _M. e. streatori_ by smaller
     size, in males hind foot less than 33.0, basilar length ordinarily
     less than 32.5, in females by hind foot ordinarily not longer than
     24, by breadth of rostrum less than 8.6, depth of braincase at
     posterior border of upper molars less than 7.6.

     _Description._--_Size._--Male: Twelve individuals of adult
     proportions yield average and extreme measurements as follows:
     Total length, 243 (205-269); length of tail, 65 (60-74); length of
     hind foot, 31 (29-32).

     Female: Corresponding measurements of six females are: 196
     (188-208), 52 (45-60?), 23.4 (22.7-24.0). An adult weighs 30
     grams.

     _Color._--As described in _Mustela erminea streatori_ except that
     least width of color of underparts averaging, in 12 males of adult
     proportions, 5 (0-11) per cent of greatest width of color of upper
     parts. Black tip of tail averaging, in same series, 26 (20-35)
     mm., which is 40 (31-58) per cent (average the same as in
     _streatori_) of length of tail-vertebrae.

     _Skull._--Male (based on 5 adults): See measurements and plates
     5-7. As described in _Mustela erminea richardsonii_ except that:
     Weight, 1.0 (0.9-1.1) grams; basilar length, 31.8 (30.6-32.5);
     length of tooth-rows more or less than (about equal to) length of
     tympanic bulla.

     Female (illustrated by 3 adults): See measurements and plates
     12-14. As described in _Mustela erminea richardsonii_ except that:
     Weight, 0.55 (0.52-0.58) grams; basilar length, 27.1 (26.7-27.5);
     breadth of rostrum more than 30 per cent of basilar length.

In comparison with _streatori_, skulls of corresponding sex average
smaller in every measurement taken with no overlap in most of those of
females. Exception is to be made for the inner lobe of M1 in males
where the size is the same. By weight males are smaller by 10 per cent
and females by 14 per cent. In relation to other parts of the skull the
tympanic bullae are narrower and in females they are shorter as well.
Comparison with _anguinae_ and _fallenda_ has been made in the accounts
of those subspecies.

_Remarks._--The smaller size, especially of females, is the principal
feature distinguishing this race from _streatori_. On the basis of
available data the female of _olympica_ is smaller than that of any
other race and hence is the smallest adult weasel of the species
_erminea_, in either the Old World or in America.

Intergradation with _streatori_ is indicated by specimens from the
southern end of Puget Sound. These specimens are intermediate in size
between typical examples of the two races concerned.

The color of the upper parts is uniform and the color pattern varies
less than in geographically adjoining races. The white color of the
underparts is restricted to a thin line on the abdominal region, but
widens out posteriorly in the inguinal region and anteriorly over the
pectoral region, throat, chin and lower lips. The upper lips are brown.
The brown of the upper parts extends around in front of each foreleg,
the two brown areas not quite meeting on the lower throat. The above
description applies to each of the 19 specimens examined with regard to
these details. Every specimen seen in the winter coat was brown, not
white.

     _Specimens examined._--Total number, 20, arranged by counties from
     north to south. Unless otherwise indicated, specimens are in the
     U. S. National Museum.

     =Washington.= _Clallam County_: Clallam Bay, 2 (1[74], 1[94]);
     Elwha, 2[10]; Johnsons Ranch, 1[60]; Happy Lake, 1[60]; Boulder
     Lake, 2[60]; near head of Soleduc River, 4500 ft., 1; 12 mi. S
     Port Angeles, 1[10]. _Jefferson County_: Hayes Cr., 2000 ft.,
     Elwha River, 2; head N Fork Quinault River, 4000 ft., 1;
     Duckabush, 3; N Fork Skokomish River, 1. _Mason County_: Lake
     Cushman, 2[76]; 4 mi. S Olympia, 1.


=Mustela erminea streatori= (Merriam)

Ermine

Plates 5, 6, 7, 12, 13 and 14

    _Putorius streatori Merriam_, N. Amer. Fauna, 11:13, pl. 2, figs.
      5, 5a, 6, 6a, June 30, 1896.

    _Putorius cicognanii_, Baird, Mamm. N. Amer., p. 161, 1858 (part
      unless no. 2395 was a female of _M. frenata_).

    _Putorius pusillus_, Baird, Mamm. N. Amer., p. 159, 1858 (part).

    _Putorius (Gale) vulgaris_, Coues, Fur-bearing animals, p. 102,
      1877 (part).

    _Mustela streatori streatori_, Miller, U. S. Nat. Mus. Bull.,
      79:96, December 31, 1912; Grinnell, Univ. California Publ. Zoöl.,
      40:101, September 26, 1933.

    _Mustela cicognanii streatori_, Hall, Murrelet, 12:22, January,
      1931; Hall, Univ. California Publ. Zoöl., 38:417, November 8,
      1932.

    _Mustela erminea streatori_, Hall, Journ. Mamm., 26:77, February
      27, 1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

    _Mustela rixosa_, Beer, Journ. Mamm., 29:296, August 31, 1948.

     _Type._--Male, adult, skull and skin; no. 76646, U. S. Nat. Mus.,
     Biol. Surv. Coll.; Mount Vernon, Skagit Valley, Skagit County,
     Washington; February 29, 1896; obtained by D. R. Luckey, original
     no. 3.

     The skull is unbroken and the teeth all are present and entire.
     The skin, in brown winter pelage, is stuffed and in good
     condition.

     _Range._--Western Washington along eastern side of Puget Sound,
     western Oregon from the Cascades to the coast, and northwestern
     California south in the humid coastal district nearly to the
     Golden Gate. See figures 25, 27 on pages 95, 149.

     _Characters for ready recognition._--Differs from _M. e.
     anguinae_, in male, by sagittal crest present and hind foot
     ordinarily less than 33.5, in female by hind foot less than 27.5,
     basilar length less than 30.2; from _M. e. fallenda_, in both
     sexes, by black tip of tail less than half of length of
     tail-vertebrae, in males hind foot less than 33.7, tympanic bulla
     about same length as, instead of longer than, upper tooth-rows;
     weight of skull less than 1-1/4 grams, in female weight of skull
     less than 0.7 grams, length of lateral side of P4 less than 4 mm.;
     from _M. e. olympica_, by larger size, in males hind foot more
     than 33.0, basilar length ordinarily more than 32.5, in females by
     hind foot ordinarily longer than 24, by breadth of rostrum more
     than 8.6, depth of braincase at posterior border of upper molars
     more than 7.6; from _M. e. gulosa_ and _muricus_, in both sexes,
     by upper lips brown (not white), light color of underparts
     extending down hind leg no farther than knee, depth of skull at
     posterior border of upper molars more than 7.7 in females and
     ordinarily more than 9.6 in males, further from _muricus_ by tail
     more than 62 in males and more than 49 in females; from _M. e.
     invicta_ by upper lips white (not brown), in males hind foot more
     than 36 and basilar length more than 35, in females hind foot more
     than 29.5 and basilar length more than 30.5.

     _Description._--_Size._--Male: Twelve adults from Blaine and
     Tillamook, Oregon, yield average and extreme measurements as
     follows: Total length, 255 (245-275); length of tail, 72 (64-80);
     length of hind foot, 31.5 (30.0-33.5).

     Female: Seven adults from Blaine and Tillamook, Oregon, yield
     average and extreme measurements as follows: Total length, 214
     (193-230); length of tail, 55 (50-63); length of hind foot, 25
     (24-27).

     _Color._--Winter and summer pelages indistinguishable; upper parts
     uniform and ranging from Raw Umber to slightly darker (16_n_), and
     about tones 1 to 3 of Dark Chocolate of Oberthür and Dauthenay,
     pl. 342; underparts white, in summer rarely with a faint buffy
     suffusion in pectoral region; color of underparts extends from
     chin, and often lower lips, posteriorly to inguinal region,
     distally on posterior sides of forelegs onto antipalmar faces of
     toes (sometimes interrupted at and above wrist) and on medial
     sides of hind legs hardly to knee. Least width of color of
     underparts averaging, in twelve adults from Blaine and Tillamook,
     10 (0-47) per cent of greatest width of color of upper parts.
     Black tip of tail, in same series, averaging 28 (24-33) mm. which
     is 40 (34-47) per cent of length of tail-vertebrae.

     _Skull._--Male (based on 12 adults): See measurements and plates
     5-7. As described in _Mustela erminea richardsonii_ except that:
     Weight, 1.1 (1.0-1.2) grams; basilar length, 33.2 (32.5-33.8);
     length of tooth-rows more or less than (about same as) length of
     tympanic bulla.

     Female (based on 7 adults): See measurements and plates 12-14. As
     described in _Mustela erminea richardsonii_ except that: Weight,
     0.64 (0.60-0.67) grams; basilar length, 28.5 (27.6-29.5); breadth
     of rostrum more than 30 per cent of basilar length.

Comparison with _anguinae_, _fallenda_, _olympica_, _gulosa_ and
_muricus_ is made in accounts of those subspecies.

_Remarks._--This weasel is rare in collections and the best material of
it was obtained by Alex Walker in Tillamook County, Oregon, where he
resides. The almost ideal series of 30 specimens showed the range of
secondary sexual, age, and individual variation expectable in the small
ermines of the Pacific Coast of the United States and was the means of
allowing satisfactory decision on questions of classification in the
related subspecies in which individuals are of comparable size.

Intergradation with each of the geographically adjoining subspecies,
_olympica_, _fallenda_, _invicta_, _gulosa_ and _muricus_ is shown by
specimens examined. With the last mentioned subspecies, intergradation
is shown by two specimens from as far south as Siskiyou County,
California, assigned to _muricus_.

The application of the name _streatori_ is difficult because it was
based on a specimen from a place where two clines cross. The
north-south cline is one of size which decreases to the south. The
east-west cline is one of intensity of color, the westernmost (coastal)
population being the most intensely colored. The type locality of
_streatori_ is at the place where two lines perpendicular to one
another, and representing the two clines, cross. This intersection is
near the place where the ranges of several subspecies meet. The
nomenclatural question is, to which one of 6 subspecies should the name
_streatori_ apply. Specimens from barely within the geographic
boundaries of four of these subspecies so closely resemble topotypes of
_streatori_ that a student with material at his disposal from only the
area about Puget Sound naturally would apply the name _streatori_ to
all of his specimens, and knowing even of the arrangement adopted in
the present account the student will have difficulty in identifying his
specimens according to it. Not only will the student find the
arrangement difficult, but probably unsatisfactory if he thinks of
_streatori_ as being the kind of animal represented by topotypes. I
conceive of topotypes of _streatori_ as being nontypical of the
subspecies; they are intergrades with _fallenda_. My aim was initially
to work out the geographic ranges of subspecies and only subsequently
to apply names, according to which type localities fell within the
previously determined geographic ranges. By this procedure no greater
weight was given to a holotype and to topotypes than to specimens from
any other locality.

Of the 40 specimens seen in winter pelage, only one is white. It is
from Darrington in the Cascade Mountains of Washington. The 39 others
are brown and I doubt that the white pelage ever occurs in the low
coastal territory included within the geographic range of _streatori_.
This subspecies resembles _anguinae_ and _olympica_ in the great
extension of area of the dark-colored upper parts at the expense of the
area of the light-colored underparts. The usual arrangement is one
where the brown of the two sides nearly meets on the midventral line
leaving a sizable, inguinal area of light color connected by a thin
line to the sizable area of light color on the pectoral region. The
light color of the pectoral area ordinarily is continuous with the
light-colored area of the throat and chin but the dark color of the
upper parts extends around in front of each foreleg. These extensions
of dark color meet on the chest in only 2 of the 56 specimens examined
in this regard. Across the abdomen the dark color is continuous in 4 of
the 56 specimens. The lower lips are brown instead of white in only 3
individuals and in 2 of these the lip of one side is brown and its
opposite is white. The variation in color-pattern is less than in
_anguinae_ or than in _fallenda_.

     _Specimens examined._--Total number, 63, arranged alphabetically
     by states, then by counties from north to south in each state.
     Unless otherwise indicated, specimens are in the U. S. National
     Museum.

     =California.= _Humboldt County_: 10 mi. NE Carlotta, 1[74].
     _Mendocino County_: Russian Gulch State Park, 1[74]. _Sonoma
     County_: Mouth of Gualala River, 1[74].

     =Oregon.= _Clatsop County_: Astoria, 1. _Tillamook County_:
     Tillamook, 16 (14[14], 1[59]); Blaine, 12 (7[14], 2[59], 1[93],
     2[76]). _Washington County_: Beaverton, 1[60]; Forest Grove,
     1[36]. _Clackamas County_: Oregon City, 1[46]. _Lincoln County_:
     Newport, 1. _Linn County_: Sico, 1[46]. _Lane County_: Vida Fish
     Hatchery, 2[101]; McKenzie Bridge, 1[101]; Mercer, 1[75]. _Klamath
     County_: Deschutes River, 6 mi. E Crescent Lake, 1[101]. _Douglas
     County_: Gardiner, 1[60]. _Curry County_: Port Orford, 1; Gold
     Beach, 2[60].

     =Washington.= _Skagit County_: N end Whidby Island opposite
     Deception Pass, 1; Hamilton, 4; Mt. Vernon, 3. _Snohomish County_:
     Oso, 550 ft., 1; Darrington, 600 ft., 1. _Pacific County_:
     Wallicut River, 2 mi. E Ilwaco, 1[74]. _Wahkiakum County_: 4 mi.
     E. Skamokawa, 3[74]. _Cowlitz County_: 4 mi. E mouth Kalama River,
     2[74]; 6 mi. E mouth Kalama River, 1[74]. _Skamania County_: 15
     mi. N Govt. Springs, 1300 ft., 1.


=Mustela erminea gulosa= Hall

Ermine

Plates 5, 6, 7, 12, 13 and 14

    _Mustela erminea gulosa_ Hall, Journ. Mamm., 26:84, February 27,
      1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

    _Putorius streatori_ Merriam, N. Amer. Fauna, 11:14, June 30, 1896.

     _Type._--Male, subadult, skull and skin; no. 81998, U. S. Nat.
     Mus., Biol. Surv. Coll.; Trout Lake, Klickitat County, Washington;
     February 3, 1897; obtained by P. Schmid, original no. 147.

     The skin is in brown winter pelage, and appears to have been made
     up from a skin split along the midventral line from the anus to
     the forelegs. It probably was dried by a trapper, is well made,
     and lacks a patch of hair on the left flank but otherwise is in
     good condition. The skull lacks the central part of the left
     zygomatic arch and the posterior two-thirds of the right one. The
     right m2 is represented only by an abortive stump or the broken
     root, and i1 and i2 on each side are absent; otherwise, the teeth
     all are present and entire.

     _Range._--Cascades of Washington from northeastern King County
     south to Mount Adams. See figures 25, 27 on pages 95, 149.

     _Characters for ready recognition._--Differs from _M. e. invicta_
     and _fallenda_, in both sexes, by anterior margin of tympanic
     bulla flush with squamosal rather than projecting below floor of
     braincase (difference slight in females), in males hind foot less
     than 33.5, weight of skull less than 1-1/4 grams, basilar length
     less than 33.9, in females by total length less than 222, hind
     foot shorter than 26, weight of skull less than 0.7 grams, basilar
     length less than 29; from _M. e. muricus_, in both sexes, by upper
     parts darker, tone 4 of Chocolate or darker (see description of
     color) least width of light-colored underparts averaging one-third
     instead of approximately two-thirds of greatest width of
     dark-colored upper parts, in males, on the average, tail more than
     65, weight of skull more than 0.90 grams, basilar length more than
     30.8 mm.; from _M. e. streatori_, in both sexes, by upper lips
     white (not brown), light color of underparts extending down hind
     legs below knee, depth of skull at posterior border of upper
     molars less than 7.7 in females and ordinarily less than 9.6 in
     males.

     _Description._--_Size._--Male: One adult and four subadults from
     Mount Rainier yield average and extreme measurements as follows:
     Total length, 253 (238-266); length of tail, 75 (70-83); length of
     hind foot, 31.5 (30-33). Corresponding measurements of 9 subadults
     from Trout Lake are: 257 (233-282); length of tail, 76 (56-83);
     length of hind foot, 30.2 (26-33).

     Female: Of adults, 2 from Mount Rainier and 2 from Trout Lake
     measure as follows: Total length, 202, 203, 216, 210; length of
     tail, 54, 52, 57, 51; length of hind foot, 24, 24, 25, 24. The
     averages for these females are 208, 54, 24.3.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that color sometimes brown in winter (with more smoky tinge than
     summer coat); upper parts ranging from tone 2 through tones 3 and
     4 of Dark Chocolate (pl. 342) into tone 4 of Chocolate (pl. 343)
     of Oberthür and Dauthenay; underparts (always white in winter) in
     summer Sulphur Yellow or more whitish; least width of color of
     underparts averaging, in 5 males from Mount Rainier, 31 (18-45)
     per cent of greatest width of color of upper parts. Black tip of
     tail, in same series, averaging 34 (29-40) mm., which is 45
     (41-50) per cent of length of tail-vertebrae.

     _Skull._--Male (based on 2 ad. and 13 sad.): See measurements and
     plates 5-7. As described in _Mustela erminea richardsonii_ except
     that: Weight, 1.0 (0.95-1.16) grams; basilar length, 32.3
     (30.9-33.4); length of tooth-rows more or less than (about equal
     to) length of tympanic bulla.

     Female (illustrated by 5 adults): See measurements and plates
     12-14. As described in _Mustela erminea richardsonii_ except that:
     Weight, 0.59 (0.53-0.65) grams; basilar length, 28.1 (27.8-28.4);
     breadth of rostrum ordinarily more than 30 per cent of basilar
     length.

In comparison with _streatori_, skulls of males and females average
smaller in every cranial measurement taken. Teeth of about same size
and males 9 per cent, and females 8 per cent, lighter. In relation to
basilar length, skull of female shallower, tympanic bullae slightly
shorter and, on the average, zygomata less expanded.

In comparison with _muricus_, males average larger in every measurement
taken; 23 per cent heavier; in relation to other dimensions, braincase
shallower at anterior end of basioccipital. Females are of about equal
size; in relation to other dimensions, braincase shallower and mastoid
and zygomatic breadths less.

Comparisons with _invicta_ and _fallenda_ have been made in the
accounts of those subspecies.

_Remarks._--This is not a strongly marked race and in most of the
characters used for differentiating it from other races it resembles
either _streatori_ to the west or _muricus_ to the southeast.
Nevertheless, there is a geographic area, the southern Cascades of
Washington, throughout which individual characters are combined in
essentially the same way and there are a few features, for instance,
smaller skull of the female, in which _gulosa_ differs from either of
its close relatives. In view of these circumstances and because the
animals can not well be included in the subspecies _streatori_ or
_muricus_, _gulosa_ is recognized as distinct. The races _gulosa_ and
_olympica_ are what might be termed weakly differentiated subspecies in
contrast to the strongly differentiated subspecies _streatori_ and
_muricus_.

Of the 21 specimens in winter pelage, 17 are white and four are brown.
The brown winter coat is distinctly paler, with more of a smoky tinge,
than the brown summer pelage. The light-colored underparts are narrower
than in the subspecies immediately to the east but are wider than in
the coastal forms to the west. The dark color of the upper parts
extends onto the chest in front of the forelegs, as in the coastal
forms, in only one of the 13 specimens in summer pelage and in it on
one side only. The black tip of the tail is short as in the coastal
forms. One specimen is in transitional pelage. It has acquired
approximately half of the white winter pelage and was taken on October
12, 1897, at Keechelus Lake.

     _Specimens examined._--Total number, 38, arranged by counties from
     north to south. Unless otherwise indicated, specimens are in the
     U. S. National Museum.

     =Washington.= _King County_: 2 mi. E Skykomish, 2[51]. _Kittitas
     County_: Keechelus Lake, 3 (1[1]); Martin, 1[1]; Easton, 3.
     _Pierce County_: James Lake, 4370 ft., Mt. Rainier, 1; Glacier
     Basin, 5935 ft., Mt. Rainier, 1; Meslers Ranch, 2000 ft., 1 mi. W
     Rainier Park, 1. _Lewis County_: Mt. Rainier Nat'l Park, 5 (1 each
     from: Paradise Park, 5400 ft.; Reflection Lakes, 4900 ft.;
     Ohanapecosh [Hot] Springs, 2000 ft.; Tahoma Creek, 1[72]; Bear
     Prairie); also in Mt. Rainier Nat'l Park, Longmire, 3 (1[72],
     1[94]). _Skamania County_: Mt. St. Helens, 6000 ft., 1. _Klickitat
     County_: Trout Lake, 18.


=Mustela erminea muricus= (Bangs)

Ermine

Plates 7, 8, 12, 13, 14 and 41

    _Putorius (Arctogale) muricus_ Bangs, Proc. New England Zoöl. Club,
      1:71, July 31, 1899.

    _Putorius streatori leptus_ Merriam, Proc. Biol. Soc. Washington,
      16:76, May 29, 1903. Type from Silverton, San Juan County,
      Colorado.

    _Putorius muricus_, Stephens, California Mammals, p. 248, 1906.

    _Putorius cicognani_, Taylor, Univ. California Publ. Zoöl., 7:298,
      June 24, 1911.

    _Mustela streatori leptus_, Miller, U. S. Nat. Mus. Bull., 79:96,
      December 31, 1912; Bailey, N. Amer. Fauna, 35:48, September 5,
      1913; Dixon, Journ. Mamm., 12:72, February 12, 1931; Whitlow and
      Hall, Univ. California Publ. Zoöl., 40:246, September 30, 1933.

    _Mustela muricus_, Miller, U. S. Nat. Mus. Bull., 79:96, December
      31, 1912; Kellogg, Univ. California Publ. Zoöl., 12:358, January
      27, 1916.

    _Mustela cicognanii lepta_, Dice, Journ. Mamm., 1:12, November 28,
      1919; Hall, Mamm. Nevada, p. 184, July 1, 1946.

    _Mustela rixosa_, Seton, Journ. Mamm., 14:70, February 14, 1933.

    _Mustela cicognanii leptus_, Miller, Journ. Mamm., 14:368, November
      13, 1933; Bailey, N. Amer. Fauna, 55:293, August 29, 1936.

    _Mustela erminea murica_, Hall, Journ. Mamm., 26:84, February 27,
      1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

     _Type._--Male, young, skull and skin; no. 9146, collection of E.
     A. and O. Bangs in Mus. Comp. Zoöl.; Echo, 7500 ft., El Dorado
     County, California; July 15, 1897; obtained by W. W. Price and E.
     M. Nutting.

     The skull has a fracture along the sagittal suture and fractures
     on the left side of the braincase but these have been glued, and
     no part of the skull is missing except in the region of the right
     P4 which part has been shot away. On the left side m2 never
     developed. Excepting this tooth and the right P4, all the teeth
     are present and entire. The skin is well made but has the soles of
     the hind feet turned up.

     _Range._--Near 5300 feet (Denver) to 11000 feet (Santa Fe Baldy);
     typically boreal but taken in Upper Sonoran Life-zone in winter at
     Denver; from central and southwestern Montana, southern Idaho, and
     Blue Mountains of southeastern Washington southward east of the
     Cascade Divide through the Salmon River Mountains and Sierra
     Nevada at least into Fresno County of California, in the Great
     Basin to central Nevada, in the Rocky Mountains into northern New
     Mexico; eastward to the Black Hills. See figure 25 on page 95.

     _Characters for ready recognition._--Differs from _M. e. invicta_
     by hind foot less than 36 and basilar length less than 35 in males
     and by hind foot less than 29.5 and basilar length less than 30.5
     in females; from _M. e. gulosa_, in both sexes, by upper parts
     lighter, tone 2 of Chocolate or lighter (see description of
     color), least width of light-colored underparts averaging about
     two-thirds instead of one-third of greatest width of dark-colored
     upper parts, in males, on the average, tail less than 65, weight
     of skull less than 0.90 grams, basilar length less than 30.8
     grams; from _M. e. streatori_, in both sexes, by upper lips white
     (not brown), light color of underparts extending down hind leg
     below knee, depth of skull at posterior border of upper molars
     less than 7.7 in females and ordinarily less than 9.6 in males,
     tail less than 62 in males and less than 49 in females.

     _Description._--_Size._--Male: An adult from Black Butte,
     California, measures: Total length, 227; length of tail, 55;
     length of hind foot, 27. Corresponding measurements of another
     from Wheeler Peak, Nevada, are: 220, 56, 26. Two subadults from
     Colorado, one from Crested Butte and another from Coventry,
     measure, respectively, as follows: 238, 227; 66, 60; 30, 30. An
     adult from Wheeler Peak, Nevada, weighs 57.7 grams and another
     from 2 mi. W Black Butte, Calif., 54.5 grams.

     Female: Two adults from Teton County, Wyoming, measure: Total
     length, 205, 200; length of tail 52,--; length of hind foot, 23,
     23.7. A subadult from 9-1/2 mi. E Pocatello, Idaho, measures: 197,
     50, 25. An adult from Wheeler Peak, Nevada, has corresponding
     measurements of 190, 42, 23, and weighs 33.8 grams.

     _Color._--As described in _Mustela erminea richardsonii_ except
     that upper parts tone 2 or lighter of Chocolate of plate 343 of
     Oberthür and Dauthenay; underparts white, Pale Buff or with faint
     wash of Sulphur Yellow; least width of color of underparts in male
     from Black Butte and one from Wheeler Peak, amounting to 65 and 59
     per cent of greatest width of color of upper parts. Black tip of
     tail, respectively, 28 and 33 mm., which amounts to 51 and 59 per
     cent of length of tail-vertebrae. In two adult females, one from
     Teton County, Wyoming, and one from Wheeler Peak, Nevada, the
     least width of the underparts amounts to 55 and 60 per cent of the
     greatest width of color of upper parts. Black tip of tail,
     respectively, 23 and 19 mm., which amounts to 44 and 45 per cent
     of length of tail-vertebrae.

     From the other subspecies of small-sized weasels of more
     northwestern occurrence, namely _anguinae_, _fallenda_,
     _olympica_, _streatori_ and _gulosa_, _muricus_ differs in lighter
     color of upper parts, wider light-colored underparts and
     relatively longer black tip of tail.

     _Skull._--Male (illustrated by 5 adults in table of measurements,
     which see): See plate 7. As described in _Mustela erminea
     richardsonii_ except that: Weight, 0.78 (Wheeler Peak) and 0.85
     (Black Butte) grams; basilar length, 30.6 (29.8-31.2); length of
     tooth-rows more or less than (approximately equal to) length of
     tympanic bulla.

     Female (illustrated by 6 adults in table of measurements, which
     see): See plates 12-14. As described in _Mustela erminea
     richardsonii_ except that: Weight, 0.60 (0.575-0.645); basilar
     length, 28.0 (27.3-29.4); breadth of rostrum approximately 30 per
     cent of basilar length.

In comparison with _streatori_, males average smaller in every
measurement taken with no overlap in most dimensions; 25 per cent
lighter; anterior margin of tympanic bulla more nearly flush with
squamosal, that is to say less protruded from braincase; in relation to
other dimensions of skull, braincase shallower anteriorly (at plane of
last molars) and deeper posteriorly (at anterior end of basioccipital).
Females average smaller in every measurement taken except mastoid and
zygomatic breadths which are actually more; 6 per cent lighter; in
relation to other parts of skull, preorbital and interorbital parts
slightly smaller; in relation to length of skull, braincase shallower.
Comparison with _invicta_ and _gulosa_ is made in the accounts of those
subspecies.

_Remarks._--The smallest males of the entire species are of this
subspecies and the females of it are barely larger than those of
_olympica_ and _gulosa_ and hence are among the three smallest. The
material now available consists only of one or a few specimens from
each of several widely separated localities. If as many specimens per
unit area were available as there are of the species _M. erminea_ from
southern British Columbia, geographic variation warranting the division
of _muricus_ into more than one subspecies might be revealed. Evidence
pointing in this direction is comprised in the pale color and small
size of the pair of adults from Wheeler Peak on the eastern border of
Nevada; the suggestion is that there is a distinct pale race of small
individuals in the isolated spots of boreal life-zone in the mountains
of the desert. The color and size of the specimens from the Toyabe
Mountains, and that from the Pine Forest Mountains, both places also in
Nevada, nevertheless, lend no support to this suggestion. Comparison of
specimens from the Rocky Mountains of Colorado with those from the
Sierra Nevada of California gives no basis for recognizing more than
one subspecies. Therefore, _Putorius streatori leptus_ Merriam with
type locality at Silverton, San Juan County, Colorado, falls as a
synonym of the earlier named _Putorius (Arctogale) muricus_ Bangs with
type locality at Echo, El Dorado County, California. Furthermore,
specimens from northern New Mexico, the southernmost known area of
occurrence for the subspecies (and for the species), are as large as
specimens from far north in the range of the subspecies, say, in
northwestern Wyoming; there is therefore no evidence of progressive
decrease in size to the southward as in advance of study I supposed
existed in _muricus_. This erroneous supposition was held because I
knew that there was a decrease in size to the southward in the species
as a whole and also in each of the subspecies _richardsonii_ and
_invicta_ directly to the north of _muricus_.

Intergradation with _invicta_ is shown by specimens from southwestern
Montana. Where the margins of the geographic ranges of _invicta_ and
_muricus_ approach one another elsewhere, low-lying territory, zonally
unsuited to the existence of the species, occurs along the Snake and
Columbia rivers, and precludes any chance of intergradation except
around the head of the Snake River Plains. Two specimens, here referred
to _muricus_, from Siskiyou County, California, in both color and
cranial characters, are intergrades with _streatori_ and might be
referred with almost equal propriety to _streatori_.

     _Specimens examined._--Total number, 52, arranged alphabetically
     by states, then by counties from north to south within each state.
     Unless otherwise indicated, specimens are in the Museum of
     Vertebrate Zoölogy, University of California at Berkeley.

     =California.= _Siskiyou County_: head of Rush Creek, 6400 ft., 1;
     Castle Lake, 5434 ft., 1. _Tehama County_: 2 mi. W Black Butte,
     6800 ft., 1. _Placer County_: ridge W of Tahoe Pines, Lake Tahoe,
     1; Blackwood Creek, 6250 ft., near Tahoe Pines, 1. _El Dorado
     County_: Fallen Leaf Lake, 6500 ft., 1[33]; Echo, 1[75]. _Tuolumne
     County_: Ten Lakes, 9200 ft., Yosemite Park, 1. _Mariposa County_:
     Vogelsang Lake, 10350 ft., Yosemite Park, 1. _Mono County_:
     Mammoth, 1[59].

     =Colorado.= _Rio Blanco County_: Marvine, 1. _Boulder County_:
     Camp Albion, 10600 ft., 1[60]; Boulder, 1[91]. _Denver County_:
     Denver, 1[57]. _Park County_: Jefferson, 1[57]. _Gunnison County_:
     near Placita in Gunnison County, 1[26]; Crested Butte, 9000 ft., 3
     (1[91], 2[19]). _El Paso County_: Turkey Creek, SW Colorado
     Springs, 6000 ft., 1[19]. _Chaffee County_: Arbourville, 1[91];
     Hancock, 1. _Montrose County_: Coventry, 6800 ft., 1[19]. _San
     Juan County_: Silverton, 1[91]; in San Juan County above
     timberline, 1[87].

     =Idaho.= _Bannock County_: West Fork of Rapid Creek, 9-1/2 mi. E
     Pocatello, 1.

     =Montana.= _Meagher County_: Camas Creek, Big Belt Mts., 4 mi. S
     Ft. Logan, 1[91]. _Beaverhead County_: Donovan, 1[91]. _County_ in
     question: Yellowstone Park, 1[75].

     =Nevada.= _Humboldt County_: Alder Creek, 6000 ft., Pine Forest
     Mts., 1. _Ormsby County_: 1/2 mi. S Marlette Lake, 8150 ft., 1.
     _Nye County_: South Twin River, Toyabe Mts., 1[91]. _White Pine
     County_: Baker Creek (8500 ft., 8675 ft., 11100 ft.), 3.

     =New Mexico.= _Taos County_: Twining, 10700 ft., 1[91]. _Sandoval
     County_: 9 mi. E Cuba, 9000 ft., 1. _Santa Fe County_: Saddle S of
     Santa Fe Baldy, 11000 ft., Santa Fe Range, 1[1].

     =Oregon.= _Wasco County_: Mill Creek, 20 mi. W Warmsprings, 1[91].
     _Klamath County_: Fort Klamath, 1[91].

     =South Dakota.= _Pennington County_: 4 mi. SE Hill City, 5300 ft,
     2[76]; Pfander's Ranch, 3 mi. SSE Hill City, 5300 ft., 1[76];
     Palmer Gulch, 3 mi. SE Hill City, 5300 ft., 1[76]; Spring Creek, 2
     mi. W Oreville, 5500 ft., 1[76]. _Custer County_: 1/2 mi. E Sylvan
     Lake, 6250 ft., 1[76].

     =Washington.= _Columbia County_: Butte Creek, 1; Stayawhile
     Spring, 5150 ft., 1:

     =Wyoming.= _Crook County_: 5 mi. NW Sundance, 5900 ft., 1[93].
     _Teton County_: Whetstone Creek, 2[76]; 1/4 mi. E Moran, 6700 ft.,
     1[93]. _Sublette County_: 1/2 mi. NE Pinedale, 7500 ft., 1[93].
     _Albany County_: 30 mi. N and 10 mi. E Laramie, 6560 ft, 1[93]; 26
     mi. N and 4-1/2 mi. E Laramie, 6960 ft., 1[93]. _Carbon County_: 8
     mi. N and 19-1/2 mi. E Savery, 8800 ft., 2[93].


=Mustela erminea? angustidens= (Brown)

Plates 7, 12, 13 and 14

    _Putorius cicognanii angustidens_ Brown, Mem. Amer. Mus. Nat.
      Hist., 9 (pt 4):181, pl. 17, 1908:

    _Mustela cicognanii angustidens_, Hay, Iowa Geol. Surv. Bull.,
      23:32, 1914; Hay, Carnegie Inst. Washington, Pub. no. 322A:252,
      October 15, 1924; Hay, _ibid_., Pub. no. 390 (vol. 2): 528, 1930;
      Hall, _ibid_., Pub. no. 473:111, 112, November 20, 1936:

    _Type._--Female, adult, skull and lower jaws lacking zygomata,
      right P2 and incisors, no. 12432, Amer. Mus. Nat. Hist.; from
      Conard Fissure, four miles west of Willcockson, Newton County,
      Arkansas; obtained sometime in the period 1903 to 1905 inclusive
      (see plates 8, 14).

    _Range._--Known only from the Pleistocene deposit in Conard
      Fissure, at the type locality in northern Arkansas.

    _Description._--_Skull._--Male (based on nos. 12437, 12441 and
      12444): See measurements and plates 7 and 8; weight, unknown;
      basilar length, 38:1 (36:6-39:2); length of tooth-rows more than
      length of tympanic bulla; breadth of rostrum measured across
      lacrimal processes less than a third of basilar length;
      interorbital breadth ordinarily equal to distance between glenoid
      fossa and posterior border of external auditory meatus; zygomatic
      breadth probably averaging approximately the same as distance
      between last upper molar and jugular foramen.

    Female (based on nos. 11766 and 12435): See measurements and plates
      8, 12-14; weight, unknown; basilar length, 34:0 (32:5-35:1);
      length of tooth-rows more than length of tympanic bulla; breadth
      of rostrum about equal to (more or less than) 30 per cent of
      basilar length; interorbital breadth less than distance between
      glenoid fossa and posterior border of external auditory meatus;
      zygomatic breadth probably less than distance between last upper
      molar and jugular foramen.

    Comparison of the cranial description given above with those of the
      American races of _erminea_ from the far north will show that
      many characters are held in common--more than with more southern
      subspecies of _erminea_.

_Remarks._--The ten specimens studied by the writer fall into two
groups of six larger individuals and four smaller. Upon comparing these
with each sex of the three species of American Recent weasels,
_frenata_, _erminea_ and _rixosa_, it is seen that size, and to some
degree shape, rule out of consideration both sexes of _rixosa_ and also
males of _frenata_. Thus we are left with females of _frenata_ and
males and females of _erminea_. So far as size is concerned, it can be
assumed that the larger specimens are females of _frenata_ and that the
smaller are males of _erminea_. This assumption has in its favor also,
the fact that the postglenoidal length of the skull accords with that
in Recent specimens. The difference in this regard in Recent animals is
that the postglenoidal length of the skull, expressed as a percentage
of the total (condylobasal) length of the skull, amounts to:

          in _frenata_             in _erminea_
  [M] ordinarily less than 46   [M] ordinarily more than 46
  [F] less than 47              [F] more than 48

In the fossils the percentage for the larger skulls is 46; for the
smaller skulls it is 48.

It may be that the ten fossil skulls are six female _frenata_ and four
male _erminea_ but I think not. In the first place a skull of different
shape, seemingly of the _frenata_ stock, is known from the deposit and
it is almost certain that two subspecies of the same species would not
occur at the same place at the same time. It is possible, of course,
that parts of the deposits were laid down at times so far apart that a
shift in geographic range of two subspecies had occurred. This one
skull, seemingly of the _frenata_ stock, is the type of _Putorius
gracilis_ Brown (see p. 404) and was regarded as the only known
specimen of _gracilis_. Regardless of the specific identity of this one
specimen named _gracilis_, the chances of obtaining otherwise from a
deposit, like that in Conard Fissure, six females of frenata and four
males of _erminea_ without a male _frenata_ or a female of _erminea_
coming to light are so slight as strongly to incline me to the view
that the six larger specimens are males of the same species to which
the 4 smaller specimens belong. By either this interpretation, or the
one initially considered (of female _frenata_ and male _erminea_), the
animals from the fissure are at least subspecifically distinct from any
American Recent weasel. Furthermore, by this latter interpretation each
sex of this weasel, _angustidens_, is intermediate between the
_frenata_ and _erminea_ stocks in the feature of postglenoidal length
which feature, at any place where the two Recent species occur
together, serves to distinguish one from the other. In the northernmost
subspecies of _erminea_ (_arctica_ for example) the postglenoidal
length in some males is no longer than in males of _frenata_.
Considering general size, _angustidens_ agrees better with _erminea_
than with frenata and this circumstance has influenced me to place
_angustidens_ as a subspecies of _erminea_.

Today, _erminea_ is not known to occur nearer Conard Fissure than
northern Iowa, more than 400 miles to the northward. In comparison with
the race there, _bangsi_, males of _angustidens_ are of approximately
the same size but in the shorter distance between the glenoid fossa and
anterior margin of the tympanic bulla, and also in the lesser
postglenoidal length of the skull, _angustidens_ resembles the
northernmost American subspecies of _erminea_. Females of _angustidens_
differ more from any living weasel than the males do. The females are
much larger than those of _bangsi_, and among living American races of
_erminea_ most closely resemble intergrades between _arctica_ and
_richardsonii_ which intergrades are found approximately 1700 miles to
the north of Conard Fissure. In females, the preorbital part of the
skull in _M. e. arctica_ is broader and in _M. e. richardsonii_
narrower than in _angustidens_. If it seems strange that females of
_angustidens_ resemble one subspecies whereas males, in size, resemble
another subspecies almost a thousand miles distant, it should be
remembered that the degree of sexual dimorphism varies much from one
subspecies to another in the Recent animals. An example is furnished by
_Mustela erminea fallenda_ and _Mustela erminea invicta_.

The assemblage of mammals from Conard Fissure includes several species
of boreal predilections which, like _Mustela erminea_, now occur only
much farther north than Arkansas. At one time the edge of the sheet of
ice was only about 200 miles north of Arkansas. It may be significant
that the cranial characters of the female ermine from the Fissure, and
qualitative cranial characters of males from there, are most nearly
approximated among Recent weasels by those which live along the
southern edge of the frozen tundra.

In view of what has been said, the possibility should be considered
that the distinctive cranial features of _angustidens_ may be the
result of evolutionary change in time as well as of geographic
variation resulting from horizontal placement.


=MUSTELA RIXOSA= (Bangs)

Least Weasel

(Synonymy under subspecies)


     _Type._--_Putorius rixosus_ Bangs, Proc. Biol. Soc. Washington,
     10:21, February 25, 1896.

     _Range._--From Norway and Switzerland eastward through Siberia and
     all the way across North America, but unknown from Iceland,
     Greenland and the Arctic islands west of Greenland; in North
     America, from the Arctic Life-zone south to Central British
     Columbia, Montana and into parts of the Upper Austral Life-zone as
     in the eastern half of the continent.

     The southern extension of range in the Appalachians (to North
     Carolina) is not duplicated in the Rocky Mountains of western
     North America probably because the region there suitable for
     _rixosa_ south of Central British Columbia and Montana is occupied
     by the almost equally small _Mustela erminea muricus_ and related
     subspecies which seem to fill the ecological role that _rixosa_
     plays where it occurs. The small size of females of _M. erminea
     cicognanii_ in New England may similarly account for the absence
     of _rixosa_ there.

_Characters for ready recognition._--Differs from both _Mustela
erminea_ and _Mustela frenata_ by tail a fourth or less of length of
head and body and without a black tip (at most a few black hairs at
extreme tip in rixosa), and from _M. frenata_ and from _M. erminea_ in
regions where it and _rixosa_ occur together, by basilar length of
skull less than 32.5 in males and less than 31.0 in females.

_Characters of the species._--Size small: Total length less than 250 in
males and 225 in females; tail a fourth or less of length of head and
body, and without a black pencil and at most with a few black hairs at
extreme tip; caudal vertebrae 11 to 16, normally 15 in _M. r. rixosa_,
and 11 in one _M. r. eskimo_ examined; skull with long braincase and
short precranial portion, thus essentially same shape as in _M.
erminea_ but the largest males of _M. rixosa_ always with a lesser
basilar length that even the smallest females of _M. erminea_ or _M.
frenata_ of the same geographic area. In fact no specimens of _M.
frenata_ have skulls so small as the largest _M. rixosa_, and skulls of
equal size of _M. erminea_ and _M. rixosa_, for example, _M. erminea
muricus_ of Colorado and _M. rixosa eskimo_ of Alaska, differ in that
when the skulls are viewed from directly above those of _rixosa_ have
the mastoid processes more prominent, or the braincase is higher in
relation to its width or both differences together prevail. Stated in
another way, comparison of skulls of equal size of _rixosa_ and
_erminea_ shows that in the latter the braincase is more nearly flat
and is wider above and in front of the mastoid processes; therefore,
the greatest breadth of the braincase equals or exceeds the mastoid
breadth, whereas the reverse is ordinarily true of _rixosa_.

_Geographic variation._--In the Old World four subspecies are currently
recognized (see Allen, 1933:316) and the same number is here recognized
in North America. Length of the tail, length of head and body and hind
foot, breadth of the rostral part of the skull in relation to its
length, and position on the side of the head of the line of demarcation
between the dark color of the upper parts and the white underparts, are
the features in which geographic variation has been detected. The
general impression is that the amount of geographic variation is much
less than in _Mustela frenata_ and only slightly less than in _Mustela
erminea_ of the same geographic area.

_Nomenclature._--It is exceptional for a species which occurs in both
the Old-and New-World to take its specific name from New World
material, especially if the name was proposed as recently as 1896; most
circumboreal species take their names from descriptions of European
specimens. Although the least weasel, _Mustela rixosa_ (Bangs) 1896,
seems now to be an exception, it may yet turn out that the first
available name was based on European material. Zimmermann (1943) shows
that the least weasel actually was named on the basis of European
material long before 1896 and concludes that the name _Putorius
minutus_ Pomel, 1853, based on a specimen from France, is the first
available name.

Because _Putorius_ nowadays is relegated to subgeneric rank under the
generic name _Mustela_, we have for consideration the name-combination
_Mustela minuta_ (Pomel). Unfortunately for Zimmermann's conclusion,
_Mustela minuta_ Pomel is not available because it is preoccupied by
_Mustela minuta_ Gervais [= _Palaeogale minuta_ (Gervais),
1848-1852--see Simpson, 1946: 2, 12], a name applied to another species
of small mustelid from the Oligocene or lower Miocene deposits of
Europe.

Some other early names thought by Zimmermann (1943:290) to have been
based on the dwarf weasel of Europe are judged to be _nomina nuda_ and
therefore are to be ignored.

The name _Mustela minor_ Nilsson 1820 was thought by Miller (1912:402)
to be a renaming, and hence a synonym, of _Mustela nivalis_ Linnaeus.
If that is the case the name does not apply to the dwarf weasel. If the
name _Mustela minor_ Nilsson was instead based on the dwarf weasel, the
name might still be unavailable, depending on rulings on secondary
homonyms, because the name might be preoccupied by _[Lutra] minor_
Erxleben 1777 which is a synonym of _[Mustela] lutreola_ Linnaeus 1766.
Two names seemingly available for weasels, and in use for them today,
which might replace _rixosa_ as the name of the species, are, first,
_Mustela boccamela_ Bechstein, 1801, of Sardinia [= _Mustela nivalis
boccamela_ of Miller, 1912, 405] and second, _Putorius numidicus_
Pucheran, 1855, of Morocco and Algeria [= _Mustela numidica_ of Allen,
G. M., 1939, 183]. As they stand in the current literature, _Mustela
numidica_ is a species distinct from the dwarf weasel and the other
name, _Mustela nivalis boccamela_, is an insular subspecies of the
mouse weasel. Zimmermann (1943:292), however, implies that _M.
numidica_ may belong to the dwarf weasel group when he says "Ob auch
_iberica_ BARR.-HAM. als Unterart zu _minuta_ POM. zu stellen ist, soll
hier nicht untersucht werden, ebensowenig die von CABRERA vermutete
Zugehörigkeit der grossen nordafrikanischen _M. numidica_ PUCH. zur
'_iberica_-Gruppe'." The answer to this problem requires a taxonomic,
rather than a nomenclatural, decision. Whether either _M. numidica_ or
_M. boccamela_ are conspecific with the dwarf weasel I cannot at this
time ascertain for want of adequate specimens. Because these two names,
_M. boccamela_, and _M. numidica_, are assigned to kinds of weasels
which are currently regarded as specifically distinct from the dwarf
weasel, and because all the other names which certainly have been
assigned to Old World populations of the dwarf weasel before 1896, so
far as I know, are _nomina nuda_ or are preoccupied, the next available
name, _Mustela rixosa_ (Bangs, 1896), is here employed.

_Remarks._--This species may have a wider geographic range in
northeastern North America than is now known. Strong (1930:7) writes
that the Naskapi Indians of the interior country of Labrador between
Hamilton Inlet and Ungava Bay "have only one name for weasel,
_mé-tah-kwut_, but they say there are three kinds in their territory, a
large, an intermediate, and a very small weasel. The latter suggests
the least weasel . . . which has not been recorded from northern
Labrador."

In the northern part of the range of the species, the winter pelage is
white and the summer pelage is brown. In the southern part of the
range, that is in the range of the subspecies _allegheniensis_, the
winter pelage is either brown or white and the time of the molt into
winter pelage is irregular; each of eleven individuals from
Pennsylvania, Michigan and Ohio, taken in December, January, February
and March is mostly white but retains some considerable part of the
brown pelage of the previous coat on top of the head and usually also
along the midline of the entire dorsum. These eleven animals include
individuals of each sex. Of each sex, some are adults and some are
subadults. Therefore, the delayed or incomplete fall molt, at present,
cannot be correlated with either sex or with any particular age. No
wild-taken specimens of _M. erminea_ or of _M. frenata_ of the same
region show this delayed or incomplete molt.

Possibly this delay or incompleteness of molt is the result of the same
cause that lies behind the birth of some _M. rixosa_ in midwinter. As
listed below, several litters of young have been found in midwinter. In
fact it appears that in the United States, young may be born in every
month of the year although, according to existing information, more
litters are produced in spring and in winter than in summer and autumn.
Many juveniles and young of _allegheniensis_ examined in study
collections clearly were born in spring but about as many seem to have
been born in midwinter as at any other time (in the light of present
knowledge) and this is in contrast to what we know of the two other
species of American weasels since their young, so far as known, are
born in spring.

One instance is worthy of detailed comment. An adult female, no. 783
Ohio State Museum, taken on January 31, 1931, at Vinton, Meigs County,
Ohio, bears the following notation on the attached label "nest plowed
out of ground. Very small young escaped--marked like parent. [F] was
nursing." The enlarged mammae on the dried skin substantiate the
statement that the female was nursing young. She has a brown mask
continuous from one ear through the eye, across the forehead and
through the other eye to the opposite ear. On each side of the body a
stripe of brown 5 to 10 mm. wide extends from the upper part of the
foreleg back to the thigh and base of the tail, uniting there with its
opposite and covering the tail. There are a few spots of brown on the
shoulders, and rump and one on the middle of the back. Otherwise the
specimen is white. One implication of the statement on the label that
the young which escaped were marked like the parent (presumably this
female parent) is that this female is a partial albino. I am more
inclined, however, to the view that there was an unseasonable activity
of the particular glands of internal secretion the hormones of which
promote embryonic growth and that these glands, or others controlled
by them, were in some way responsible for an abnormal progress of molt,
or for a reversal of molt in that one molt began before the previous
molt had been completed.

Excepting this one specimen, no. 783 from Vinton, Ohio, all of those in
transitional pelage indicate that the direction of the molt pattern is
the same as in _M. frenata_ and _M. erminea_. That is to say, the
autumnal molt begins on the midventral line and the molt in spring
begins on the mid-dorsal line. Furthermore, the normal progress of each
molt appears to follow the same pattern that has been described above
for _Mustela frenata_.

A possible explanation of unseasonal molt in the southeastern area of
occurrence of the species _Mustela rixosa_, and a possible explanation
of the abnormal molt of the female from Vinton, Ohio, is that the
species has only relatively recently invaded the area, and has had
insufficient time to adjust the physiology of its molting mechanism to
the longer periods of daylight that obtain later in autumn and earlier
in spring than farther north. In the other two species of American
weasels, the change in length of periods of light, it will be recalled,
is known to indirectly control both molt and some changes in the sexual
cycle. Wright (1942B:109) has shown that molt in spring precedes by one
or two months the birth of young in _M. frenata_, that the two
phenomena are correlated in a way that is statistically significant,
and recognizes that progressively longer periods of daylight may be the
causal stimulus. The suggestion made above that _M. rixosa_ does not
live in New England or in the Rocky Mountains of the western United
States because each of the two areas already is inhabited by weasels of
almost equally small size, is in line with the idea that _rixosa_ is a
recent immigrant to America, or more precisely that _rixosa_ arrived
later than _erminea_.

_Natural History._--Habitat and Numbers.--Soper (1946:136) recounts
that near the junction of the Antler and Souris rivers, Manitoba, this
species occurs "both in the river valleys and on the upper prairies,"
and later (1948:55), with reference to the Grand Prairie of the Peace
River region of Alberta, writes that the least weasel "inhabits both
parklands and mixed wood forest environments."

At most times, wherever found, the least weasel is regarded as rare.
Not only mammalogists regard it as rare and as a desirable catch, but
Indians likewise value it, probably because of its rarity. For example,
Osgood (1901:69-70), who caught a female least weasel at Tyonek,
Alaska, writes that: "The natives regard the capture of one of these
rare animals as a piece of great good fortune. One old Indian who
frequently visited our cabin told us that his brother who had caught
one when a small boy had in consequence become a 'big chief'; and he
assured me that since I had caught one I must surely be destined to
become a man of great wealth and power."

Swenk's (1926:313-330) account of the species in Clay County, Nebraska,
shows, however, that the animal was far more abundant in 1916 and 1917
than subsequently and inferentially than it was before 1916. Clearest
proof of multiannual fluctuation is provided by P. O. Fryklund's
(Swanson and Fryklund, 1935:120-126) receipt of weasels from Roseau
County, Minnesota. From 1895 to 1932 he had approximately equal
opportunity to receive least weasels each year. Those which came to his
attention were distributed by years as follows: 1895-1927, 7
individuals in all; winter of 1927-28, 3 individuals; winter of
1928-29, 59 individuals; 1929-1930, 84 individuals; 1930-1935, 3
individuals. "These records indicate a very definite increase in the
abundance of least weasels in the Roseau region [in] the two years from
the autumn of 1928 to the spring of 1930. Mr. Fryklund has handled 166
least weasels in his 40 years in Roseau County, and of these, 143 were
taken in the two years mentioned."

The maximum home range of the least weasel is two acres and a weasel
seldom travels farther than ten rods from its burrow according to
Polderboer (1942:146) who, in the period December 20, 1939, to January
2, 1940, studied four least weasels and one long-tailed weasel on a 144
acre farm in Butler County, Iowa.


Behavior

Of the voice, Llewellyn (1942:441) records that his captive specimen
taken in Virginia uttered a shrill shriek when seizing prey or when
teased. When excessively annoyed the weasel also emitted musk.

The sense of smell is used in hunting as was witnessed by George L.
Fordyce; he observed a least weasel following the scent of a
_Peromyscus_ and saw the least weasel overtake and kill the mouse
(Seton, 1929 (2):637).

At a nest in a clover stack, in Manitoba, Criddle (1947:69), on
December 27, 1946, found the least weasel "to have been rather remiss
in its sanitary habits as its pile of dung was almost, or quite,
touching the nest and only just to the side of its entrance." There
were 117 voids.


Enemies

The great-horned owl, barn owl and long-tailed weasel are to be counted
as enemies since Nelson (1934:252) found the fur, skull and other
fragments of the skeleton of a least weasel in one of 26 pellets of the
great-horned owl in Wisconsin; Handley (1949:431) found the skull and
other skeletal remains of a least weasel in one of 22 pellets of the
barn owl in Virginia; and Polderboer, Kuhn and Hendrickson (1941), in
Iowa, found the remains of a least weasel in the den and scats of a
_Mustela frenata_. A domestic cat in Michigan killed a least weasel
(Dearborn, 1932B:277).


Food

Mice are killed by the least weasel biting into the back of the head
and neck according to Allen (1940:460) who reported upon the growth of
five young, from Michigan, that he had in captivity. He further states
that a weasel was able to kill a mouse in 30 seconds. One large
_Microtus_ introduced into the cage slept with a weasel for several
days and ate parts of the mice that the weasel killed but then the
weasel killed this mouse! Llewellyn (1942:440-441), in writing of a
captive from Virginia, says: "When a live mouse was placed in the cage,
the weasel sprang upon it almost instantly. Grasping the mouse by the
back of the head, the weasel bit its victim through the skull several
times in rapid succession and held on with its sharp teeth. The sound
of the teeth piercing the bone was distinctly audible at a distance of
several feet. During this interval the weasel hugged the mouse closely
with its fore legs and pressed it firmly to its belly through a kicking
motion of the hind legs. The hold on the back of the head was not
relinquished until the mouse was dead. The killing took only a few
seconds. Upon releasing the mouse the weasel usually came to the front
of the cage and inspected the observer for an interval of several
seconds after which it returned to its prey and began its meal at once.
Sometimes the blood would be licked from the wound in the back of the
head or perhaps an ear would be chewed a bit and the blood licked off,
but never did the weasel 'cut the throat' of its prey and 'suck the
blood.'

"The weasel ate the head and brain first, beginning at the back of the
head and working forward. Just before reaching the nose the process was
reversed and eating then proceeded from the base of the skull toward
the tail of the mouse. The tip of the nose, maxilla with teeth, and the
tail seemed to be the parts least preferred; they were not eaten when
an abundance of food was present. At no time did the weasel place its
front feet on the mouse in an attempt to hold it. A second or third
mouse was killed immediately upon being placed in the cage even though
the first one had not been consumed. The weasel, however, usually
returned to the partially eaten mouse and finished it before starting
on a new one. Upon completing a meal, especially if the meal had been
particularly bloody, the weasel rubbed its chin on the bottom of the
cage, scooting along and appearing more snakelike than normal. Whenever
I attempted to remove a mouse, or partially eaten one, from the cage,
the weasel hung to the mouse tenaciously, and often allowed itself to
be lifted up in this manner.

"In the six days that the weasel was kept in captivity it was fed 10
house mice having a total weight of 118 grams. As no food was given on
one day, the amount of food eaten is probably slightly below the actual
capacity of the animal. Since the weasel weighed only about 32 grams,
the average amount of food eaten a day was slightly in excess of
one-half the weight of the animal."

Polderboer (1942:146-147) found in three dens, in Iowa, bits of
_Reithrodontomys_ (harvest mice) and _Peromyscus maniculatus_ (deer
mouse), and in the digestive tract of one least weasel there was a bone
fragment and a few hairs of a deer mouse. In the account, given beyond,
of a nest, Criddle (1947:69) records the Pennsylvania meadow mouse
(_Microtus pennsylvanicus drummondi_) and the Gapper red-backed vole
(_Clethrionomys gapperi_) as prey at Treesbank, Manitoba. The same
author, concerning the same place, earlier (1926:199-200) wrote that in
1922 the meadow mouse, _Microtus minor_, "went into winter quarters in
great numbers and its homes were well stocked with provisions . . . all
went well until the middle of February, 1923. Then, within a few days,
each was taken possession of by a least weasel (_Mustela rixosa_) and
the inhabitants were quickly destroyed. One dwelling was occupied by
one of these weasels for about two weeks during which time I observed
that it had dragged several mice over the snow to its temporary home.
This residence was examined in April, and in it were discovered six
dead _Microtus minor_, one _Evotomys_, the head of another, and at
least six or eight remnants of small rodents including _Microtus
drummondi_, these last remains being chiefly indicated by the
hair-lined nest of the weasel.

"The homes of 27 other vole communities examined at this time were all
found to have been entered by weasels, the inhabitants having been
killed and partly eaten. Moreover, the weasels had made the homes
temporary centers from which they raided other rodent habitations in
the vicinity. Thus from being an abundant animal this vole was reduced
to insignificance in the course of a few weeks, while all other kinds
of mice had suffered severely from the same enemy."

An instance of predation on _Peromyscus_, revealing some of the methods
of capturing prey, is recounted by Seton (1929 (2):636-637) who quotes
a letter to him from George L. Fordyce, of Youngstown, Ohio, as
follows: "While out in the field this morning (Dec. 26), walking along
the bank of a ravine at the edge of our golf course, I saw a
Field-mouse run out of the bushes into the rough grass that is just
outside of the fair-green of the course. In another instant, what I
thought at first to be a white Mouse came out at the same place. The
Mouse ran into a wheel track, and disappeared under the grass, coming
out about 6 feet from where it went in. The white animal followed
through the same course, and when it came out, I saw that it was a
small Weasel, very little larger than the Mouse, and that it was
following the trail of the Mouse by scent.

"For a time the Mouse ran in circles, and zigzagged about, often . . .
within 4 or 5 feet of the Weasel; but the latter seemed so intent on
the trail, that it did not notice the Mouse to one side. After a time
the latter started toward the open golf course; and when the Weasel
reached the point where the trail was straight, it sighted the prey,
made a sudden dash forward, and, although 25 feet behind, overtook the
Mouse while it was going 3 or 4 feet.

"For a few seconds, they seemed to fight, until the Weasel got the
Mouse by the throat, and started for the bushes, dragging the body.
When it came to within about three feet of me, I moved a little to see
what it would do. It dropped its victim, and ran into the ravine. The
Mouse had a drop of bright red blood in the center of its white throat.
I waited near by for 15 or 20 minutes, thinking the Weasel might come
back, but it did not show up again; even an hour later, the Mouse had
not been disturbed."

There are two suggestions, but no proof that I know of, in the
literature that the least weasel eats insects. Abbott (1884:27-32--1st
ed., 1884) gives considerable information on the food (some insects
included) of the "little weasel" which he describes (_op. cit._; 27) as
having "a little pointed tail of a uniform brown color." Although this
suggests _Mustela rixosa_, Abbott mentions on the next page (page 28)
that a specimen of the smaller weasel measured six and a half inches
from the tip of the snout to the base of the tail and that the tail
itself measured two and a fourth inches to the tip of the last caudal
vertebra. These measurements indicate that _Mustela erminea_ was
involved. Because of the uncertainty as to the species of _Mustela_
involved, Abbott's interesting data on food, nest and behavior are not
recorded in the present work. Seton (1929 (2):636) says that of several
least weasels brought to D. Nicholson at Morden, Manitoba, most of them
decayed so quickly that they could not be saved as specimens. To Seton
this indicated that insects were an important part of the food of the
weasels.

In summary: Least weasels are known to eat harvest mice, deer mice,
meadow mice and red-backed mice; it is suspected that they eat also
insects.


Reproduction

Polderboer (1948:296) has taken six specimens in "northeastern Iowa
[in] . . . January and December--all males in winter pelage. None of
these males showed signs of sexual activity; in all, the testes were
retracted and diminutive in size. . . . A male least weasel in brown
pelage was taken November 17, 1945, at Marion, Iowa. This specimen had
large testes that had descended into the scrotum. The testes, when
removed, were about the size of medium-sized garden peas. Microscopic
examination of the testes and the vasa deferentia showed mature sperms
to be present. . . ."

On July 1, 1917, in Clay County, Nebraska, a nest with four young was
found (Swenk, 1926:321). On July 29, 1939, an adult and five young were
plowed out of the ground in Allegan County, Michigan; one of the two
young males weighed 40.5 grams two days after capture (Allen,
1940:459-460). On August 12, 1932, ten young with the mother, were
found in Roseau County, Minnesota (Swanson and Fryklund, 1935:125).
September appears to have been the month of birth of a specimen, no.
8472 in the Carnegie Museum, taken on November 24 in Pittsburgh,
Pennsylvania. In October, a young least weasel is recorded from
Pennsylvania (Winecoff, 1930:313). Early December was the time of birth
of a specimen, approximately 10 weeks old, no. 88077, University of
Michigan, taken on February 21 in Allegan County. On December 25, 1927,
in Washington County, Pennsylvania, "five full-sized, though
young . . . animals were caught under the same pile of corn fodder"
(Sutton, 1929:253). The first week of January seems to have been the
time of birth of a juvenile, no. 88080, University of Michigan, taken
in Livingston County, Michigan, on March 27, 1943, since the specimen
is approximately seven weeks old. On January 15, 1929, in Washington
County, Pennsylvania, four young with the eyes yet unopened were
obtained from a nest (Sutton, 1929:254). On January 25, 1928, young,
the eyes of which may not yet have been open, were taken from a den in
Washington County, Pennsylvania, by Winecoff (1930:313), who records
other young having been taken in the same month as well as in February.
On March 10, a female from North Portal, Saskatchewan, gave birth to
four young (Dunk, 1946:392). On April 18, 1916, four young, half grown,
were taken in Nebraska (Swenk, 1926:317). On April 2, 1929, three young
were found in Roseau County, Minnesota, according to Swanson and
Fryklund (1935:125) who remark that: "The Pennsylvania and Minnesota
records show that least weasels may be born any time from July to early
February in the northern states." Now, with all of the above records
available, it turns out that November, May and June are the only months
in which young least weasels have not been reported. Of course some of
the young, for which the ages were not specified, were born in
preceding months. Even so, the data now available suggests that, in the
United States, young least weasels may be born in every month of the
year. The number per litter is 3, 4, 4, 4, 5, 5, and 10, yielding an
average of 5.

The rate of growth of the young has not been studied enough to allow of
judging if it differs significantly from that of other species of the
genus. Allen (1940:459-460), however, tells us that of the three young
females and two young males captured on July 29, 1939, in Allegan
County, Michigan, one male that was killed on July 31, 1939, weighed
40.5 grams. The male remaining alive increased from 46 grams (August 5)
to 62.5 grams on September 20, having eaten 63 mice while in captivity.
The females in the period of August 5 to September 4 increased in
weight as follows: 41 up to 49 grams; 44 to 50 grams; and 47 to 58
grams, having eaten, by September 26, 60, 64 and 65 mice.

Concerning a nest in which young were found, Sutton (1929:254) writes
that on January 15, 1929, near Burgettstown, Washington County,
Pennsylvania, an animal was seen to enter a small hole in a creek bank.
After the observer dug in a distance of approximately six inches an
adult, female least weasel was seen and obtained. Back of the animal,
the hole, which turned sharply downward, was full of water. The weasel
first seen was a female nursing young. A chamber, to the side of the
hole, filled with dead grass, comprised a nest containing four young
with the eyes yet unopened. Several nests occupied by adult least
weasels or by least weasels that were old enough to shift for
themselves have been found. Polderboer (1942:145-147) in the winter of
1939-40, on a 144 acre farm in Butler County, Iowa, found four least
weasels living, singly, in burrows dug by moles and pocket gophers. The
nests therein made by mice were used by the least weasels. Winecoff
(1930:312-313) mentions one den in Pennsylvania that contained the
remains of only mice, "and not a hint of a feather." Above, in the
account of food of the least weasel, Criddle's (1926:199-200) account
of the havoc wrought by least weasels among the meadow mice (_Microtus
ochrogaster minor_) has been given. In this account he mentions the
fur-lined nests of the weasels that had appropriated the homes of the
_Microtus_. Criddle's (1947:69) later account of a nest at Treesbank,
Manitoba, is as follows: "A Nest of the Least Weasel.--When a least
weasel finds its way into a locality that has a large number of mice in
it, it selects for its home one of their nests that has been made in a
well concealed place. This it immediately starts to improve by lining
it with hair plucked from its victims before eating them; and as long
as sufficient numbers of mice remain in the district the weasel
continues adding their hair to the nest, so that the thickness of its
walls give one a good idea of the length of time it has been in use.
The nest is not only used for sleeping in, as most of the food is
consumed in it. Frozen mice are taken in to be thawed out and the
weasel carries those it has recently killed in to prevent them getting
frozen, or perhaps to have them warm for its next meal.

"On January 27, 1946, my son Percy called my attention to a nest that
he had just uncovered in a clover stack that we were using. This nest
had originally been made by a Drummond's vole, _Microtus pennsylvanicus
drummondii_, and taken from it by the least weasel, _Mustela rixosa_,
the tracks of which had been noticed about the stack yard since the
first snow in early November.

"The nest had evidently been in use for at least three months and the
continual additions made to its walls had been so great that they were
nearly an inch thick of hair matted together so closely that it
appeared to be felt. The hair alone weighed nearly 22 gm., so that with
this for protection the weasel must have been warm and comfortable
through the severest winter weather.

[Illustration: FIG. 28. Map showing occurrences and probable geographic
ranges of the subspecies of _Mustela rixosa_ in North America.]

"In the nest were two red-backed mice, _Clethrionomys gapperi_, one of
which had the base of its skull eaten out. No hair had been removed
from either of them, but a _Microtus_ lying in a side tunnel some feet
away had the long hair plucked from its back and sides. In and close
about the nest were found forty-three front parts of mice skulls which
had evidently been discarded because of the sharp teeth in the
maxillaries. Seven full stomachs and eleven hind feet of adult
_Microtus_ with parts of leg bones were disclosed in, or under, the
weasel's bed and a few small bits of skin with hair attached were
scattered among the plucked hair of the nest.

"This weasel seems to have been rather remiss in its sanitary habits as
its pile of dung was almost, or quite, touching the nest and only just
to the side of its entrance. It was composed of 117 voids all of which
contained much hair and broken bone.

"Six other mouse nests found in the same stack, or others adjoining it,
had been thinly lined with hair. One of these had two mice in it, a
red-backed with its brain eaten out and a _Microtus_ with some hair
plucked from its neck. Another nest contained the front part of a skull
with teeth and the hind feet and tail of a red-back. Besides the mice
found in the nests seven others were discovered tucked away in side
tunnels. One of these mice had most of the hair plucked from its back.
Whether all these mice and nests belonged to the same weasel or not I
am unable to say, but it is usual for them to have several nests in the
area surrounding the one that is used as their headquarters or home."


=Mustela rixosa eskimo= (Stone)

Least Weasel

Plates 14 and 15

    _Putorius rixosus eskimo_ Stone, Proc. Acad. Nat. Sci.
      Philadelphia, 1900:44, March 24, 1900.

    _Putorius (Gale) vulgaris_, Coues, Fur-bearing animals, p. 102,
      1877 (part).

    _Putorius rixosus Bangs_, Proc. Biol. Soc. Washington, 10:21,
      February 25, 1896 (part); Merriam, N. Amer. Fauna, 11:14, June
      30, 1896 (part).

    _Mustela rixosa eskimo_, Miller, U. S. Nat. Mus. Bull., 79:96,
      December 31, 1912; Swenk, Journ. Mamm., 7:327, November 23, 1926;
      Hall, Univ. California Publ. Zoöl., 30:421, March 19, 1929.

     _Type._--Female, age in question, no. 848 in Acad. Nat. Sci.
     Philadelphia; Point Barrow, Alaska; July 25, 1898; obtained by E.
     A. McIlhenny. Type not seen by me.

     _Range._--Alaska and Yukon Territory. See figure 28 on page 180.

     _Characters for ready recognition._--Differs from _M. r. pygmaea_
     of eastern Asia in longer tail, averaging 11 rather than 16 per
     cent of length of head and body, and in study skins reaching only
     to heel instead of to point between heel and toes; from _M. r.
     rixosa_ in shorter tail averaging 16 rather than 19 per cent of
     length of head and body and not extending beyond outstretched hind
     feet in study skins; white of underparts extending dorsally as a
     reëntrant angle from upper lip to behind eye, rather than
     delimited dorsally by a boundary between white and brown color
     that extends straight across cheeks from upper lip to side of body
     well below eye and ear; breadth of rostrum measured across
     lacrimal processes more, instead of less, than 85.5 per cent of
     orbitonasal length; from _M. erminea_ of same region by basilar
     length of skull less than 32; tail less than 50 and lacking black
     pencil.

     _Description._--_Size._--Male: The original describer lists
     measurements of topotypes as follows: Total length, 204, 230;
     length of tail, 28, 31; length of hind foot, 20, 22. Allowing 5
     per cent for shrinkage, the hind feet of 5 topotypes yield an
     average measurement of 23 for the hind foot.

     Female: Measurements of two topotypes are: Total length, 184, 180;
     length of tail, 25, 25; length of hind foot, 24, 18. In four other
     topotypes the hind feet, allowing 5 per cent for shrinkage, yield
     an average of 21.

     _Color._--Winter pelage all white, rarely with few white hairs in
     tip of tail but no black pencil; summer pelage with upper parts
     about Raw Umber and tone 3 of Chocolate pl. 343 of Oberthür and
     Dauthenay; underparts white, extending over upper lip, insides of
     limbs and over all four feet. Line of demarcation between
     underparts and upper parts extends from upper lip posterodorsally
     to behind eye down to base of ear, up behind ear for a third or
     more of its height, and back along side of body. Tail unicolor all
     around and same color as upper parts. Least width of color of
     underparts averaging 83 per cent of greatest width of color of
     upper parts.

     _Skull._--Based on topotypes; see measurements and plates 14 and
     15; weight, 0.82 (0.74-0.93) grams in males, and 0.80 and 0.84 in
     two females; basilar length, 29.5 (27.6-30.1) in males and 27.8
     (27.1-28.8) in females; otherwise as described in _M. e.
     richardsonii_.

_Remarks._--Among the earliest specimens preserved was one by Edward W.
Nelson in the course of his explorations of the Upper Yukon, and one in
1874 by L. T. Turner from St. Michaels, Alaska. Bangs, in 1896 (p. 22)
mentioned the occurrence of the species in Alaska, but it was not until
1900 (p. 44) that Stone named the subspecies, and then principally on
the basis of specimens obtained two years before by E. A. McIlhenny.

The large size, broad skull, light color and short tail are the
distinguishing subspecific characters of the race _eskimo_, and the
three characters first mentioned are distinguishing features also of
the subspecies of _Mustela erminea_, namely _arctica_, which inhabits
the same region. Possibly _eskimo_ also will be found on Banks Island
and the other Arctic islands between Alaska and Greenland, as is _M. e.
arctica_; at the present time no specimens of _Mustela rixosa_ are
known from these islands although some race of rixosa would be expected
to occur there.

Animals from southern Alaska average slightly smaller than those from
northern Alaska, and this decrease in size toward the south probably
represents intergradation with _M. r. rixosa_. Further evidence of
intergradation is furnished by the short tail of the specimen from 15
miles east of Atlin; in other particulars this specimen agrees with the
subspecies _rixosa_ to which it is here referred. Nevertheless, the
short tail, and color pattern, namely reëntrant angle of white behind
the eye, is to be seen in all Alaskan specimens examined in the brown
pelage, even in no. 107591, from Tyonek on Cook Inlet, which Osgood
(1901:69) and Swenk (1926:323) thought might not differ from the
subspecies _M. r. rixosa_.

Each of four male topotypes, hardly subadult in age, probably of a
single litter, is much larger than any other specimen seen from Point
Barrow. The basilar length, for example, is 31.9 as against 29.5, and
the weight of the skull (with lower jaws) is as much as 1.5 grams, as
against 0.93 in the heaviest of the other males. Initial examination of
materials from Point Barrow raised the suspicion that two distinct
species were represented--_rixosa_ and a larger one possibly allied to
_M. nivalis_ of the Old World. Nevertheless, further study almost
completely allayed the suspicion because the only difference
discernible is one of size, and it is supposed that additional
specimens will bridge the gap in size and show that _M. r. eskimo_ at
Point Barrow averages larger than the adult specimens now available
indicate. The four large males of subadult age are nos. 42814-42816 and
42818 of the American Museum of Natural History.

Of the fourteen adult and subadult skulls examined, two display lesions
resulting from infestation of the frontal sinuses by nematode
parasites. None of the young skulls show such infestation.

     _Specimens examined._--Total number, 42 as follows. Arranged
     alphabetically by Territory and District and unless otherwise
     indicated in the United States National Museum.

     =Alaska.= Barrow and Point Barrow, 19 (8[2] 7[74], 2[1], 1[50]);
     Wainwright, 1[57]; Mts. back of Icy Cape, 1[77]; west of Beechey
     Point, 1[2]; west edge of Colville River Delta, 1[2]; Koyukuk
     River, 16 mi. above Beetles, 1; upper Yukon, 1; Fort Yukon, 1;
     Stephens Village, 1; Wales, 1[57]; McDonald Creek, tributary of
     Salcha Slough, 1; near head of Toklat River, 1; head of Kantishna
     River, 1; St. Michael, 4 (2[74]); Tyonek [= Tyonek], 1; Bethel, 3;
     vic. Bristol Bay, 1.

     =Yukon.= La Pierre's House, 1; Klotassin River, tributary of White
     River, 1.


=Mustela rixosa rixosa= (Bangs)

Least Weasel

Plates 14 and 15

    _Putorius rixosus_ Bangs, Proc. Biol. Soc. Washington, 10:21, pl.
      1, fig. 6, pl. 2, fig. 6, pl. 3, fig. 4, February 25, 1896;
      Merriam, N. Amer. Fauna, 11:14, pl. 2, figs. 7, 7a, June 30,
      1896.

    _Putorius pusillus_, Baird, Mamm. N. Amer., p. 159, 1858.

    _Putorius (Gale) vulgaris_, Coues, Fur-bearing animals, p. 102,
      1877.

    _Mustela rixosa_, Thomas, Proc. Zoöl. Soc. London, p. 168, March,
      1911.

    _Mustela rixosa rixosa_, Miller, U. S. Nat. Mus. Bull., 79:96,
      December 31, 1912; Swenk, Journ. Mamm., 7:327, November 23, 1926.

     _Type._--Female, adult, skin and skull; no. 642 Bangs Coll. in
     Mus. Comp. Zoöl.; Osler, Saskatchewan; July 15, 1893; obtained by
     W. C. Colt; original no. 79 according to describer.

     The skull lacks the basioccipital, basisphenoid, and left
     zygomatic arch. The "crowns" of the lower canines are missing;
     otherwise the teeth are present and entire. The skin is fairly
     well made, with soles of hind feet up, in good condition and in
     summer pelage.

     _Range._--From northern British Columbia and Great Slave Lake
     south on the west side of the Rocky Mountains to Ootsa Lake,
     British Columbia, and on the east side of the Rocky Mountains,
     south to central Montana, North Dakota and Minnesota; eastward in
     Canada, entirely north of St. Lawrence River, to Atlantic Ocean.
     See figure 28 on page 180.

     _Characters for ready recognition._--Differs from _M. r. eskimo_
     in longer tail averaging 19 rather than 16 per cent of length of
     head and body and extending beyond outstretched hind feet in study
     skins, rather than to a point short of tips of toes; boundary
     between brown upper parts and white underparts extending straight
     across cheeks from upper lip to side of body well below eye and
     ear, rather than with reëntrant angle from upper lip carrying
     white upward to point behind eye, and with breadth of rostrum
     less, instead of more, than 85.5 per cent of orbitonasal length;
     from _M. r. campestris_ by smaller size: hind foot less than 25 in
     males and ordinarily less than 22 in females; in males total
     length less than 216 and tail averaging less than 34, and in
     females total length averaging less than 182 and tail averaging
     less than 29; color said to average darker; from _M. r.
     allegheniensis_ by three average differences, namely lighter
     color, longer tympanic bullae and larger size of males; from _M.
     frenata_ and _M. erminea_ of same region by basilar length of
     skull less than 32; tail less than 50, and lacking black pencil.

     _Description._--_Size._--Male: Six adults and subadults from
     Shaunavon, Saskatchewan, yield average and extreme measurements as
     follows: Total length, 202 (188-208); length of tail, 32.5
     (31.5-34.0); length of hind foot, 22.8 (21-24).

     Female: One adult and 3 subadults from the same area yield average
     and extreme measurements as follows: Total length, 172
     (162-190.5); length of tail, 27.4 (24-34); length of hind foot,
     19.6 (17.5-22).

     _Color._--Winter pelage all white, rarely brown; as described in
     _M. r. eskimo_ except that line of demarcation on side of head
     between upper parts and underparts passes almost straight back
     without the dorsally directed reëntrant area of white behind the
     eye and ear; least width of color of underparts averaging 52 per
     cent of greatest width of color of upper parts.

     _Skull_ (Based on those from Shaunavon, Sask.)--See measurements
     and plates 14 and 15; weight, 0.88 (0.70-0.98) grams in males and
     0.55 (0.54-0.56) in females; basilar length, 29.5 (28.4-30.4) in
     males and 26.1 (24.7-27.0) in females; otherwise as described in
     _M. e. richardsonii_.

_Remarks._--As early as 1858 (p. 159) Baird recognized an individual of
this race from Pembina, Minnesota, as pertaining to a distinct species.
Although he used for it the specific name _pusillus_ originally
proposed by DeKay for a small weasel from the state of New York, Baird
wisely noted that the specimen he described "may be different from the
New York species. . . ." After preparing this account, Baird included a
second specimen, from Fort Steilacoom, Washington Territory, which he
thought might be the same, but the differences that he was careful to
point out, in the light of later knowledge, show it to be of the
species _Mustela erminea_. Only a few other naturalists followed Baird
in distinguishing the least weasel as a separate species until Bangs in
1896 (p. 21) clearly differentiated it and proposed for it the name
_Putorius rixosus_, which continues in use today and applies to the
species.

The accumulation at the National Museum of Canada, through the energy
of Dr. R. M. Anderson, of a good series of specimens from Saskatchewan
in the general vicinity of the type locality allows for the first time
an adequate conception of the amount of secondary sexual variation and
individual variation and permits recognition of subspecific characters
to differentiate between _M. r. rixosa_ and the subspecies _eskimo_ and
_campestris_. In comparison with the subspecies _allegheniensis_ the
basis for segregation is less clear and will remain somewhat in doubt
until additional adults of _allegheniensis_ from, say, Pennsylvania,
become available with accurate external measurements taken in the flesh
and especially with complete skulls.

Intergradation with the subspecies _eskimo_ is suggested by the short
tail of the specimen from fifteen miles east of Atlin, British
Columbia; in other particulars that specimen, a skin-alone, agrees with
the subspecies _rixosa_. Intergradation with _campestris_ is indicated
by increased size of some specimens from North Dakota, and is suggested
with _allegheniensis_ by the color of specimens from Wisconsin and
Illinois. Three specimens from Winona County, in southeastern
Minnesota, unfortunately are skulls-alone without external
measurements. Also, two of these skulls are of young animals. The one
adult, unsexed, is from Crystal Springs. Selected cranial measurements
are: basilar length, 28.5; length of tympanic bulla, 10.9. These
measurements accord with those of males of the subspecies _rixosa_ to
which the specimens from Winona County, therefore, are here assigned.
The possibilities have not been excluded, however, that the adult is an
unusually large female of the subspecies _campestris_ or a male of
_allegheniensis_ that has tympanic bullae longer than average for that
subspecies.

Some hesitation is felt in assigning the specimens, 8 in all, from
eastern Canada to the subspecies _rixosa_. The skin-alone from Eagle
River and the skin, with part of the skull, from St. Michael Bay, are
in transitional pelage and are of no help in appraising subspecific
characters. The one adult specimen which does have a complete skull is
from an island south of the Comb Hills. This animal in all respects
agrees with selected individuals of _M. r. rixosa_ from Saskatchewan,
but each of the five other skins in summer pelage has spots of dark
brown color on the breast. Only about one specimen in three of _rixosa_
from Saskatchewan is similarly marked. Furthermore, on some of the
specimens from eastern Canada the spots are larger than on any of the
animals from farther west. The greater frequency of brown spots on the
breast, the larger average size of these spots, and the darker average
coloration of the upper parts are suggestive of geographic variation,
the existence of which has to be proved by additional and more complete
specimens from eastern Canada. For the time being, specimens from there
are tentatively assigned to the race _rixosa_.

Of 56 subadult and adult skulls only 3 (1 North Dakota; 1 Calgary,
Alberta; and 1 Island S Comb Hills, Queb.) display lesions resulting
from infestation of the frontal sinuses by nematode parasites. None of
the young skulls shows such infestation.

     _Specimens examined._--Total number, 87 as follows. Arranged
     alphabetically by provinces and states and within each from north
     to south. Unless otherwise indicated, specimens are in the United
     States National Museum.

     =Alberta.= Miette River, 1[77]; 5 mi. NW Camrose, 1[77]; Camrose,
     2 (1[77], 1[31]); "near Camrose," 2[77]; Forks Blindman and Red
     Deer rivers, 1[60]; Innisfail, 1[86]; Veteran, 1[93]; Diddsbury [=
     Didsbury], 1; Calgary, 2 (1[93], 1[2]); Shepard, 1[86].

     =British Columbia.= Clarks Ranch, Halfway River, Peace River Dist,
     1[85]; 15 mi. E Atlin, 1[8]; Wistaria, P. O., 3 (2[77], 1[85]);
     Ootsa Lake, 1[85].

     =Labrador.= Davis Inlet, 1[60]; 30 mi. upriver and 20 mi. toward
     Groswater Mts., Eagle River, 1; St. Michael Bay, 1.

     =Mackenzie.= Old Fort Reliance, 1[2]; Fort Resolution, 2; Fort
     Smith, 1.

     =Manitoba.= Gypsumville, 1[86]; Lake St. Martin Reserve, 1[86].

     =Minnesota.= _Roseau County_: Cedarbend, 2[14]; Grimstad, 1[14];
     America, 2 (1[14], 1[74]); Malung, 1[74]; Norland, 1[41]; Falun, 3
     (1[14], 1[74], 1[41]); Palmville, 1[41]; Spruce, 1[74]; Stokes,
     1[74]. No locality more definite than Marshall County, 1[14].
     _Clay County_: Moorhead, 1[36]. _Winona County_: "near" Whitman,
     1[34]; Altura, 1[98]; Crystal Springs, 1[98].

     =Montana.= Sun River Valley, 1; Wibaux in Wibaux County, 1.

     =North Dakota.= _Walsh County_: Grafton, 15 (3[60], 1[93], 5[2],
     2[14], 1[74], 1[1], 1[76]). _McHenry County_: 4 and 4-1/2 mi. N
     Upham, 2. _Wells County_: 1[36]. _Morton County_: Mandan, 1[60].

     =Ontario.= Algoma Dist: Tatnall, near Oba, 1[86]. Moose Factory,
     1[75].

     =Quebec.= Island S of Comb Hills, James Bay, 1[9]. _Saguenay
     County_: Natashkwan, 1.

     =Saskatchewan.= Osler, 1[75]; "near Regina," 1[77]; Dollard,
     2[31]; Shaunavon (and "near" and 1 mi. NE), 9[77]; Klintowel P. O.
     (about 15 mi. N of Eastend), 1[77]; Eastend and "near" Eastend,
     2[77].


=Mustela rixosa allegheniensis= (Rhoads)

Least Weasel

Plates 14, 15 and 41

    _Putorius allegheniensis_ Rhoads, Proc. Acad. Nat. Sci.
      Philadelphia, 1900:751, March 25, 1901.

    _Putorius rixosus allegheniensis_, Cory, Mamm. Illinois and
      Wisconsin, p. 378, 1912.

    _Mustela allegheniensis_, Miller, U. S. Nat. Mus. Bull., 79:96,
      December 31, 1912.

    _Mustela rixosa allegheniensis_, Swenk, Journ. Mamm., 7:328,
      November 23, 1926.

     _Type._--Probably male adult, skin and skull, no. 6195, Acad. Nat.
     Sci. Philadelphia; near Beallsville, Washington Co., Pa.; about
     1885 or 1886; obtained by Robert Hawkins.

     Type not seen by me.

     _Range._--Wisconsin, northern Illinois, northern Indiana,
     Michigan, Ohio, Pennsylvania east to Dauphin County and south in
     the mountains to northwestern North Carolina. See figure 28 on
     page 180.

     _Characters for ready recognition._--Distinguished from _M. r.
     rixosa_ by three average differences, namely, darker color,
     shorter tympanic bullae, and smaller size of males; from _M. r.
     campestris_ in smaller size: hind foot less than 25 in males and
     less than 22 in females; in males total length less than 216 and
     tail averaging less than 34, color averaging darker; from _M.
     frenata_ and _M. erminea_ of same region by basilar length less
     than 31, tail less than 45, and lacking black pencil.

     _Description._--_Size._--Male: An adult or subadult from Fair
     Oaks, Pa., a subadult from Finleyville, Pa., and an adult from
     Huttonsville, W. Va., measure, respectively as follows: Total
     length, 206, 194, 191 (average 197); length of tail, 37, 32, 28
     (32); length of hind foot, 23 in each. An adult from Roanoke,
     Indiana, weighs 40.6 grams.

     Female: Two young from Leasuresville, Pa., and Middle Paxton
     Twp., Pa., measure, respectively, as follows: Total length, 188,
     172; length of tail, 33, 30; length of hind foot, 20.5, 21. An
     adult from Monroeville, Ohio, weighs 40.5 grams and a young
     individual from Middle Paxton Twp., Pa., 39.3 grams, and a
     subadult from Swan Creek Exp. Station, Allegan Co., Mich., weighs
     49 grams.

     _Color._--Winter pelage either all white, or brown as in summer;
     upper parts about Raw Umber, or tone 2 of Carbo Brown of pl. 342
     of Oberthür and Dauthenay. Underparts white at least on thoracic
     region; approximately three-fourths of specimens with brown rictal
     spot at angle of mouth or with this area covered by brown upper
     parts which extend down on each side and meet on the underparts in
     about one specimen out of three; upper lips and hind feet
     ordinarily brown; toes of forefeet ordinarily white (see under
     remarks for details of color pattern). Least width of color of
     underparts in the specimens in which the dark color of the upper
     parts does not encircle the body averages 60 per cent of greatest
     width of color of upper parts, or including all specimens the
     percentage is 42.

     _Skull_ (based on specimens from Pa. listed in table of cranial
     measurements, which see and plates 14 and 15).--Basilar length
     29.7 and 28.6 in male and 28.0 in female; weights unavailable;
     otherwise as described in _M. e. richardsonii_. The length of the
     tympanic bullae seems to be actually less, and less in relation to
     the basilar length, than in other American subspecies of _M.
     rixosa_.

_Remarks._--Robert Kennicott's mention in 1859 (p. 245) of what seems
to be this subspecies is the earliest reference to it that I can
identify in the literature. He used the specific name _pusillus_ and it
was not until 1900 that Samuel N. Rhoads proposed the name _Putorius
allegheniensis_. Since 1900, several records of occurrence have been
published which have made the geographic range of this race better
known.

An adequate number of specimens has been gathered only from Ohio and
from western Pennsylvania. Many from Ohio are without accurate external
measurements taken in the flesh. The majority of the specimens from
Pennsylvania owe their preservation to the willingness of local
officials, who pay bounties on weasels, to save the skins of _Mustela
rixosa_. These specimens ordinarily comprise the skin with locality but
because the feet, external measurements in the flesh, and skulls are
unavailable, the material is far from adequate and to give an accurate
notion of the usual or average cranial characters of _allegheniensis_
in Pennsylvania, skulls from there are especially desirable.

A smaller percentage of the specimens from Ohio than from Pennsylvania
have the brown color of the upper parts meeting on the underparts.
Also, more of the specimens from Ohio are lighter colored and this
suggests intergradation with the subspecies _campestris_ and _rixosa_
to the westward.

From Pennsylvania 23 animals in brown pelage are available. In 5 there
is a rictal spot at the angle of the mouth; in 5 the area is white and
in 13 the brown color of the upper parts is continuous over the area in
question. Only 2 of 23 have the upper lips white. Eight have the color
of the upper parts meeting on the venter thus restricting the white of
the underparts to the chin, throat, and pectoral region, and 6 of these
have a white area in the inguinal region as well. The toes of the
forefeet are white in 3 of 4 animals suitable for examination in this
regard and the hind feet are marked with white in 3 of the 8 animals
which have the hind feet preserved. _Mustela rixosa_ in Pennsylvania
parallels the species _Mustela frenata_ in that in this relatively
humid area of the northeastern United States the color of the upper
parts is darker and the area of the dark-colored upper parts is
increased at the expense of the area of the light-colored underparts.
Also _Mustela erminea_ in this same region (range of the subspecies
_Mustela cicognanii_) shows the same tendency to darker color of upper
parts and their extension in area at the expense of the area of the
light-colored underparts, or was mentioned above.

It is difficult to account for the seeming absence of the species from
New England and all that part of Canada and the United States south of
the St. Lawrence River and northeastward from Pennsylvania. The size of
females of _M. erminea cicognanii_ in that territory is so little more
than in _rixosa_ that the latter possibly cannot successfully compete
with the _erminea_ stock which may already occupy the ecologic niche to
which _rixosa_ is adapted. It will be remembered that in western North
America in territory seemingly climatically suitable for _rixosa_ it
occurs no farther southward than the line below which _M. erminea_ has
become reduced to a size comparable with that of _M. rixosa_.

Of 41 subadult and adult skulls assigned to this subspecies 24 have
obvious lesions in the frontal sinuses evidently resulting from
infestation by nematodes. More in detail, none of the specimens from
Illinois (3 individuals), Pennsylvania (3 barely subadult), or West
Virginia (2) displays lesions. From Wisconsin, Indiana, Virginia and
North Carolina there is one specimen each and each specimen displays
lesions. From Ohio, 17 of 23 specimens display lesions. From Michigan 3
of 8 specimens display lesions; 2 adults and one subadult have lesions
and 5 subadults do not have lesions.

     _Specimens examined._--Total number, 102 as follows: Arranged
     alphabetically by states and within each state by counties from
     north to south. Unless otherwise indicated, specimens are in the
     United States National Museum.

     =Indiana.= _Huntington County_: Roanoke, 1. _Wells County_:
     Harrison Township, 1[76].

     =Illinois.= _Lake County_: Deerfield, 3[60]; no locality more
     definite than county, 1[60] _Cook County_: Northfield, 1[60]; La
     Grange, 1[18].

     =Michigan.= _Tuscola County_: 8 mi. N Caro, 1[76]. _Santilac
     County_: Deckerville, 1[76]. _Allegan County_: Swan Creek Exp.
     Station, 1[76]; Swan Creek Farm, 1[76]; T. 2N, R. 14W, 1[76];
     Allegan, 1[76]. _Livingston County_: George Reserve, 1[76]; 1/2
     mi. N Unadilla, 1. _Oakland County_: Rochester, 1[76]. _Macomb
     County_: Romeo, 1[76]. _Washtenaw County_: 5 mi. SW Ann Arbor,
     1[76]. _Branch County_: vic. Coldwater, 1[76].

     =North Carolina.= "near Marshall," 1.

     =Ohio.= Northern part of state, 1[81]. _Williams County_: Stryker,
     1[60]. _Lucas County_: Monclova, 1[60]. _Erie County_: Sandusky,
     2[76]; marsh near Sandusky, 1[76]; Berlin Heights, 1[76]; no
     locality more definite than county, 1[2]. _Wood County_: 10 mi. NE
     Bowling Green, 1[76]; Bowling Green, 4[76]; 3 mi. E Bowling Green
     1[76]; Plain Township, 1[2]; Portage Township, 1[60]. _Loraine
     County_: Wellington, 1[81]. _Huron County_: west of Monroeville,
     1[76]. _Summit County_: Ira, 3[81]. _Portage County_: Suffield,
     1[81]. _Hancock County_: Vanburen, 1[76]; Findlay, 1[81]; 9 mi. S
     Findlay, 1[76]; no locality more definite than county, 7 (2[76],
     2[81], 3[2]). _Mahoning County_: Ellsworth, 1. _Crawford County_:
     "near Crestline," 1[81]. _Delaware County_: Sunbury, 1[2]; Lewis
     Center, 1[81]; no locality more definite than county, 1[81].
     _Licking County_: Johnstown, 1[2]. _Fairfield County_: Baltimore,
     1[81]; Violet Township, 1[81]. _Meigs [= Gallia?] County_: Vinton,
     1[81].

     =Pennsylvania.= _Erie County_: McKeen Twp. 1. _Crawford County_:
     Springboro, 1[1]; Pymatuning Swamp, between Hartstown and
     Shermansville, Sadsbury Twp., 3[9]. _Mercer County_: Shenango
     Twp., 1. _Lawrence County_: Little Beaver Twp., 1. _Butler
     County_: Leasuresville, 1[9]; Clearfield Twp., 1; Valencia, 1[9].
     _Armstrong County_: Ford City, Burrell Twp., 1. _Indiana County_:
     Smicksburg, 1; N. Mahoning Twp., 2; White Twp., 1. _Allegheny
     County_: South Hills, Pittsburgh, 1[9]; "near Pittsburgh," 1[9];
     Fair Oaks, 1[9]. _Westmoreland County_: Bolivar, 1. _Dauphin
     County_: Middle Paxton Twp., 1. _Washington County_: Finleyville,
     1; Rea, 5; Beallsville, 1[1]; Claysville, 1. _Green County_: Deep
     Valley, 1; Waynesburg, 1; Jefferson, 1; Cumberland Twp., 1.
     _Fayette County_: Acme, 1[9]; _Somerset County_, 1. _Lancaster
     County_, 1.

     =West Virginia.= _Randolph County_: Huttonsville, 1.

     =Wisconsin.= _Sauk County_: Sumpter Twp., 1[60]. _Dodge County_:
     Beaver Dam, 1[50]. _Dane County_: Madison, 1; McFarland (=
     MacFarland), 1.


=Mustela rixosa campestris= Jackson

Least Weasel

Plates 14 and 15

    _Mustela campestris_ Jackson, Proc. Biol. Soc. Washington, 26:124,
      May 21, 1913.

    _Putorius pusillus_, Aughey, Sketches of the physical geography and
      geology of Nebraska, p. 119, 1880, Omaha.

    _Mustela rixosa campestris_, Swenk, Journ. Mamm., 7:329, Nov. 23,
      1926.

     _Type._--Female, adult, skin and skull; no. 171490, U. S. Nat.
     Mus., Biol. Surv. Coll.; Beemer, Cuming County, Nebraska; April
     18, 1911; obtained by G. Sharp; x catalogue no. 8440.

     The skull is unbroken. On the left side, C1 and P2 are missing;
     the other teeth are present and entire. The skin is excellently
     made and in a good state of preservation.

     _Range._--South Dakota, Nebraska and Iowa. See figure 28 on page
     180.

     _Characters for ready recognition._--Differs from _M. r. rixosa_
     and _M. r. allegheniensis_ in larger size: Hind foot more than 25
     in males and ordinarily more than 22 in females; in males total
     length more than 216 and tail averaging more than 34; color
     possibly slightly paler than in _M. r. rixosa_ and averaging paler
     than in _M. r. allegheniensis_; from _M. frenata_ and _M. erminea_
     of the same region by basilar length less than 32; tail less than
     50, and lacking black pencil.

     _Description._--_Size._--Male: Four adults from Nebraska yield
     average and extreme measurements as follows: Total length, 231
     (225-237); length of tail, 36 (32-39); length of hind foot, 29
     (28-31).

     Female: Six adults from Nebraska yield average and extreme
     measurements as follows: Total length, 192 (184-225); length of
     tail, 35 (28-40); length of hind foot, 23 (20.5-26).

     _Color._--Winter pelage ordinarily white; as described in _M. r.
     eskimo_ except possibly paler and certainly with line of
     demarcation on side of head between upper parts and underparts
     passing almost straight back without the dorsally directed
     reëntrant angles of white behind the eye and ear; least width of
     color of underparts in four specimens from Nebraska averaging 80
     (49-89) per cent of greatest width of color of upper parts, but in
     a fifth animal in summer pelage the brown color of the upper parts
     encircles the body.

     _Skull._--See measurements in table and plate 15; weight 1.1 grams
     (male from Brown Co., S. D.); basilar length, 30.7 in male from
     Clay Co., Neb., and 28.8 in female from same county; otherwise as
     described in _M. e. richardsonii_.

_Remarks._--In his revisionary treatment of the American races of
_Mustela rixosa_, Myron H. Swenk (1926:313) credits Samuel Aughey with
recording this animal, _M. r. campestris_, from Nebraska, as early as
1880, under the name _Putorius pusillus_. In 1908, Swenk recorded the
animal from the same state under the name _rixosus_ and in 1913 the
race _campestris_ was formally named by H. H. T. Jackson.

On the testimony of a friend who had previously obtained several
specimens for him, Swenk (1926:321) records the least weasel from
Oshkosh, Garden County, Nebraska, which is a marginal record of
occurrence to the southwest for _M. r. campestris_.

At an early stage in the study of American weasels the writer examined
the specimens from Nebraska saved by Mr. Myron H. Swenk and recorded
measurements of them. However, at the time of writing this account the
specimens were not available for examination and the account of
coloration is accordingly incomplete.

The large size, particularly the large external measurements, comprises
the principal distinguishing character of this subspecies of the least
weasel.

Of the four adults examined from Iowa and South Dakota one exhibits
lesions such as result from infestation of the frontal sinuses by
nematodes.

     _Specimens examined._--Total number, 21 as follows. Arranged
     alphabetically by states and by counties, from north to south in
     each state. Unless otherwise indicated, specimens are in the
     United States National Museum.

     =Iowa.= _Howard County_: Chester, 1[12]. _Palo Alto County_:
     Emmetsburg, 1[65]. _Kassuth County_; Algona, 1[65]. _Clayton
     County_: National, 1. _Storey County_: Nevada, 1[65]. _Wapello
     County_: Ottumwa, 1[65]. _Henry County_: Mount Pleasant, 1[66].

     =Nebraska.= _Holt County_: Page, 1[35]. _Madison County_: Norfolk
     1[35]. _Cuming County_: Beemer, 1. _Hamilton County_: Chapman,
     1[35]. _Clay County_: Inland to 1 mi. east thereof, 7[35].

     =South Dakota.= _Brown County_: shore of Sand Lake, S. 15 T. 126N,
     R. 62W, 1. _Day County_: Waubay Migratory Waterfowl Refuge, 1.
     _McCook County_: Salem, 1[102].


=MUSTELA FRENATA= Lichtenstein

Long-tailed Weasel

(Synonymy under subspecies)


     _Type._--_Mustela frenata_ Lichtenstein, Darstellung neuer oder
     wenig bekannter Säugethiere, pl. 42 and corresponding text
     unpaged. 1832.

     _Range._--From southern Canada southward over all of the United
     States, México, Central America, Venezuela, and the republics of
     western South America to southern Perú and extreme northern
     Bolivia. All the life-zones from Alpine Arctic to Tropical are
     inhabited. In the extremely desert region of southeastern
     California and western Arizona the species is scarce or possibly
     absent although recovery of a skull (see under account of _M. f.
     neomexicana_) from near the center of this region at Potholes on
     the Colorado River, and a reported occurrence in the mountains of
     Baja California, México, indicate that a few individuals of the
     species live in favorable habitat even in this desert region.

_Characters for ready recognition._--Differs from _Mustela erminea_, in
regions where the two species occur together, by tail more than 44 per
cent of length of head and body and by postglenoidal length of skull
less than 46 per cent of condylobasal length in males and less than 48
per cent in females (see under characters of the species); from
_Mustela rixosa_ by presence of black pencil on tail, caudal vertebrae
more than a fourth (2/5-3/4) of length of head and body, basilar length
of skull more than 34 mm.; from _Mustela africana_ by absence of thenar
pad on forefoot, underparts without longitudinal, median, abdominal
stripe of same color as upper parts, upper lips narrowly (rather than
broadly) edged with color of underparts, longest facial vibrissae
extending to or behind posterior margin of ear; presence of p2; more
inflated (see pls. 23 and 30) tympanic bullae.

_Characters of the species._--Size large: Total length 300 to 550 mm.;
tail two-fifths to seven-tenths of length of head and body, with
distinct black pencil at end; caudal vertebrae 19 to 23; skull with
long precranial portion; postglenoidal length, expressed as a
percentage of the condylobasal length, less than 47 in females and
ordinarily less than 46 in males; upper parts brown; light-colored
underparts, in summer pelage, tinged with buffy or yellowish and
continuous from chin to inguinal region; some subspecies (southwestern
United States, México, Central America, and Florida) with white or
yellowish facial markings which do not occur in any other American
species of the genus _Mustela_.

_Geographic variation._--Forty-two subspecies are recognized, and the
species is geographically more variable than any of the other 3
American species. Color, color-pattern especially on the head, relative
proportions of the tail, hind feet, body including the head, and shape
and size of the skull are the principal features in which geographic
variation has been noted. The variation in the skull extends to the
basicranial region (shape and size of tympanic bullae and related
structures), interorbital region and preorbital region.

_Natural History._--Habitat and Numbers.--As has already been remarked,
the long-tailed weasel is absent from the extreme desert of the
southwestern United States and northwestern México. Possibly the
absence of water to drink is the limiting factor. In southern Nevada
the finding of weasels only in places that were well watered, even
though small rodents suitable as food for weasels were even more
abundant in the surrounding desert, supports this possibility that the
absence of water to drink is the limiting factor. Also at Berkeley,
California, in early December of 1927 in the canyon at the head of
Dwight Way and in the autumn and winter of 1928 in Strawberry Canyon on
the campus of the University of California, I trapped extensively for
this species in different habitats and obtained, in all, four
individuals no one of which was farther than 10 feet from water. The
lesser cruising range of the individual weasel than of, say, the
coyote, probably explains why, in an arid region, for example
Pahranagat Valley, Nevada, only the meadow mice and their riparian
associates are preyed upon by the long-tailed weasel whereas the coyote
preys upon these riparian rodents and also upon the kangaroo rats and
other rodents which are so abundant in adjoining habitats that are
devoid of water.

In areas where water is available every few hundred yards, no
particular habitat seems to be avoided in summer providing there is
food for the long-tailed weasel. In winter (January and March) there
obviously was a choice of habitat, possibly occasioned by more abundant
food or more satisfactory shelter, or both, in Centre County,
Pennsylvania, where Glover (1943B) found the population density in the
chestnut-oak habitat to be one weasel per 6.5 acres in areas of tree
cuttings and slash and one weasel per 13.3 acres in the open forest. In
the scrub oak-pitch pine forest type the population was one weasel per
26.4 acres in tree cuttings and slash and one weasel per 38.2 acres in
the open forest. No weasel was found in an area of 9.6 acres comprising
a wood lot, the edge of the forest, abandoned fence rows and an
abandoned orchard. The two types of forest in which he did find
weasels, 25 in all, comprised 381.6 acres. Glover's (_op. cit._) data
is the only precise information known to me on actual numbers of
long-tailed weasels in a given area of any considerable size.

Fluctuations which I elsewhere (1946:57) have designated as multiannual
fluctuations occur in this species but seemingly not in the degree that
they do in _Mustela erminea_. This difference between the two species
is to be expected because _M. frenata_ does not range so far northward
toward the polar regions as does _M. erminea_ and populations of most
kinds of animals in the polar, at least in the arctic, regions are
subject to more extreme and more regular fluctuations than are kinds of
animals in temperate or tropical regions. Indication of the means by
which decrease in the weasel population is brought about is afforded by
Osgood's (1935:156) observations around Rutland, Vermont. In the late
winter of 1934, tracks indicated that weasels left their usual haunts
and hunted cross lots, vainly trying to find food. Testing of the small
mammal population in the spring and summer of 1934 showed that it was
at low ebb. In the fall of 1934 mice and shrews were abundant again but
weasels seemed to be entirely absent. The decrease in the population of
weasels lagged behind the decrease in the population of the herbivorous
prey as did the subsequent increase; this, of course, is the normal
relation of carnivorous species of mammals and their prey, at least in
and above the Transition Life-zone.

The average distance away from the central den which four weasels (sex
unspecified) traveled in a single night at Ames, Iowa, was 312 feet;
the maximum distance was 642 feet. These data were obtained in the
winter of 1939 by Polderboer, Kuhn and Hendrickson (1941:115) who
studied the tracks in the snow. In Manitoba, Criddle and Criddle
(1925:143) noted that a female which lived in their basement often
wandered more than half a mile away in search of food. In Michigan,
Quick (1944:75) found the maximum distance traveled in one day (=
night?) by a large male to be 3.43 miles although two miles was the
average distance traveled by this individual. In 1942, from January 4
to March 4, in Centre County, Pennsylvania, Glover (1943B) studied
tracks of 11 males and 10 females, in newly fallen snow, and
ascertained that the distance traveled in a single night averaged 704
(60-2535) feet for the male and 346 (20-1420) feet for the female. The
weasels in the open timber traveled farther per trip than those in the
brushland and dense stands of trees.


Behavior

An adult female (now the holotype of _Mustela frenata nevadensis_) seen
running across a field, and, I think, unaware of my presence, at every
bound bent her back up so far that she reminded me of a measuring worm.
For part of the time when running, the tail was held off the ground
straight out behind, and then, for a while, inclined upward at an angle
of about 45°. Another weasel that I saw in the daytime, and that I
think was unaware of my presence, was bounding along among the
_Baccharis_ bushes on the south-facing slope of Dwight Way Canyon,
Berkeley, California. This individual, at each bound, arched the back
up so high as to remind me, again, of a measuring worm.

The long-tailed weasel is a land mammal and unlike its close relative,
the mink, is seldom seen in the water. That it can swim, however, is
attested by the capture of one while it was swimming across the Río
Ramos in México (Davis, 1944:381). Also, Green (1936), in May, in
Gratiot County, Michigan, saw a weasel, running with a _Peromyscus_ in
its mouth. The weasel dropped the mouse, entered the water and swam to
a hole among stones.

More instances of climbing, than of swimming, have been reported in the
literature for the long-tailed weasel. Seton (1929 (2):625) quotes
William M. Graffius of Pennsylvania as having seen a weasel closely
pursue a red squirrel nearly to the topmost branch of a large hemlock.
When the squirrel loosed its hold and dropped into a stream, the weasel
descended to the ground and caught and killed the squirrel when it
emerged from the water. Pearce (1937:483), in central New York State,
on July 29, 1931, watched a weasel chase a chipmunk up a black cherry
tree ten inches in diameter, and noted that the first rush carried the
weasel "straight up the trunk for approximately 10 feet, where it
hesitated momentarily before continuing. Then, instead of climbing
vertically, it made progress by traveling in short ascending spirals
around the trunk, scarcely making 3 feet in height for each circuit of
the tree. Upon reaching the limb by which the chipmunk escaped, the
weasel followed out along this in the same spiral manner. This limb had
a diameter of about 4 inches at its base and extended upward at an
angle of perhaps 20 degrees above the horizontal . . . it made its way
head first almost down to the ground, using the same spiral mode of
progress, but at a leisurely pace. . . . While traveling down the side
limb it appeared practically to wrap its sinuous body around the limb."

A male long-tailed weasel, from Colorado, which I kept captive was
often fed freshly killed mice. These I thrust through one of the small
openings in the wire mesh. The weasel quickly learned to seize any part
of a mouse thus introduced and his tugging aided in getting the mouse
into the cage. Occasionally a mouse too large to be got through the
mesh had to be withdrawn. In such an instance, if the weasel had
already had hold of the mouse, he would screech frightfully. I have
heard no other vocal sounds from a weasel except a kind of purring.

The sense of smell apparently is well developed; at any rate it is keen
enough to allow the weasel to follow the trail of an intended victim by
the scent left by the latter. Murie's (1935:321-322) account, for
example, of a weasel pursuing a snowshoe rabbit gives clear evidence
that the weasel relied on scent in following the rabbit.

A captive male weasel obtained at Gainesville, Florida, stamped his
hind feet when annoyed (Moore, 1945:259).

A male from Colorado that I kept for months in a cage at Lafayette,
California, was several times found in a sleep so deep that he was
awakened with difficulty. Seton (1929 (2):629-630) writes: "In my small
menagerie, I have had half-a-dozen Weasels of the New York species.
Their sleeping dens are arranged so as to be easily and silently
opened. Several times I have lifted the lid to find the weasel in a
deep sleep--a sleep so profound that I had to poke him vigorously with
a stick before he awoke, looked up, and rushed forth with a little puff
of wrath, and a little puff of smell."

Feces and urine were ordinarily deposited in one particular place by
each of the captive weasels that I have observed. Hamilton (1933:294)
records that a large male _M. f. noveboracensis_, in a week, averaged
10 evacuations every twenty-four hours, that urination immediately
precedes defecation, and describes the feces as black or brown, long
and narrow and often spiral-shaped owing "to the matted fur of some
rodent that had been eaten." Quick (1944:77) writes, concerning four
winter dens in Michigan, that "The latrines of weasels were in the
entries of used dens and scats could be collected there by the
handful." Polderboer, Kuhn and Hendrickson (1941:116) in the spring of
1939 at Ames, Iowa, gathered scats "from latrines found at the
entrances of burrows and from latrine chambers found within burrows."
Scats were found by them in the linings of some nests.

Courage of a high order might be credited to the long-tailed weasel
because individuals have attacked animals much larger than the weasels.
Actually, however, in few if any of these instances was the motive for
attack known. That a hawk was attacked is suggested by Soper's
(1919:45) account of _Mustela frenata noveboracensis_ wherein he
repeats a story told to him of a hawk observed in unsteady flight, and
obviously in distress, which when it plummeted to earth was with a
weasel which escaped from the observer. Charles Tatham, Jr., of
Cambridge, Massachusetts, according to Seton (1929 (2): 630, 631)
observed one that attacked his dog.

Persons and long-tailed weasels have figured in some rather strange
encounters. For example, Oehler (1944:198) recounts that in the autumn
of 1940 at Cincinnati, Ohio, an animal, mistakenly thought to be a
chipmunk, was seen to dash into a hollow log whereupon pounding on the
log brought out the weasel which bit and clung to the hand of one man
whose companion was bitten when he attempted to free the man that was
bitten first.

Seton (1929 (2): 631) writes that on the night of September 5, 1897, on
Roosevelt's old ranch, near Medora, North Dakota, a man turned over his
saddle (which was lying on the ground) to dislodge what was thought to
be a pack-rat. The animal was a long-tailed weasel which attacked him.
It ran up his legs a number of times aiming at his throat before being
killed by a dog.

Criddle and Criddle (1925:146) wrote: "August 20, 1919.--A _longicauda_
in the Insectary ran at me this morning apparently with a view to
intimidating. It uttered a shrill cry while making the attack, but
retreated after advancing within two feet." The same authors (_op.
cit._: 147) further write that a "Long-tailed Weasel was caught in a
trap set for gophers, and, on being released by Miss M. Criddle, at
once turned upon its liberator and bit savagely at her boot. It then
moved a short distance away to a tub of water, where it drank
thirstily, merely glancing at the observer from time to time while
doing so, and then ran off out of sight.

"Mr. T. Criddle records a similar experience. After liberating a large
weasel from a trap, it immediately rushed at him and persisted in its
attack with such ferocity that it was three times picked up and thrown,
on each occasion to a greater distance, before it finally abandoned its
offensive.

"We have no record of a weasel making an unprovoked attack upon
anyone."

Wight (1932: 164) in Michigan, detected a weasel attacking a hen. The
weasel fled at Wight's approach but returned and attacked him several
times. Finally the weasel went around Wight to reach the hen. In
Wight's words "There was no evidence of infuriation, but rather a well
directed offense at the one object, regardless of its size, which stood
between the weasel and an opportunity to satisfy its desire to kill,
which was probably based upon the uncontrollable urge of hunger pangs."

Weasels of each of the three North American species have been
successfully kept in captivity. A type of cage satisfactory for keeping
the animals in the laboratory is described by Bissonnette and Bailey
(1940:761-763). Some of the captives used their teeth to break glass
water-containers and to gnaw slivers of wood from the cages. Ingested
slivers of wood and bits of broken glass caused the deaths of some of
the captives. Weasels kept by me all were of the species _Mustela
frenata_. They thrived on a meat diet but I was always careful to give
them, every few days, if not each day, some small rodents entire,
thinking that the bits of bone and fur ingested might, in some way
unknown to me, keep the digestive tract in better condition than would
flesh devoid of hair and bone.

Three young weasels approximately the size of mice, in the Okefinokee
Swamp of Georgia, were obtained by a hunter who, according to Harper
(1927:303), raised them by feeding "milk for a few days, and then fresh
meat." Litters of young born in captivity have been successfully raised
by the mothers (Hamilton, 1933) and success in getting the animals to
breed in captivity and to rear their young is recorded by Wright
(1948A). He has found, however, that the majority of his captive adult
males show no interest in mating when placed with females in heat. He,
therefore, uses only selected males and when a female in heat is to be
bred, he places one of his responsive males with her one day, another
of his responsive males with her the second day and thus alternates a
couple of males for three or four days. Even so, slightly fewer than
half of the females which were thus bred produced young.

A weasel in the white winter coat was used by Audubon and Bachman
(1856:177, Quarto edit.) to drive rabbits out of their burrows in the
same fashion that ferrets commonly are used. Although these naturalists
refer to their animal as an ermine it probably was _Mustela frenata
noveboracensis_, the long-tailed weasel. The animal's teeth (probably
canines) were blunted and a long cord tied on its neck. With the aid of
this weasel 12 rabbits were caught in one morning and more than 50 in
four weeks.


Enemies

Little is recorded concerning enemies of weasels and it may be that
other vertebrates are not an important factor in removing the annual
increase. Errington (1935:195-198), in Iowa, found four, putrid
weasels about dens of red foxes, _Vulpes fulvus_. No remains of weasels
were found in the feces of the foxes and it appears that the foxes do
not eat the weasels. The label on an adult female specimen of _M. f.
spadix_ from Boone County, Iowa, bears the date May 10, 1938, and the
annotation, by T. G. Scott, "fox-killed." Bailey (1931:328) recounts
that "Weller saw a coyote carrying one in its mouth" at an elevation of
11,500 feet in the Pecos Mountains of New Mexico. The type specimen, a
young female, of _M. f. peninsulae_ from Hudsons, Florida, according to
Rhoads (1894:155) ". . . was caught in the woods by a cat." Barber and
Cockerell (1898:189) mention one that was killed by a dog in Mesilla
Park, New Mexico. Moore (1945:258) records the death of a weasel in
Florida. Circumstantial evidence indicated that it was killed by the
bite of a water moccasin. In the Biological Surveys Collection of
mammals in the United States National Museum, the label with the skull
of an adult male weasel, No. 160663, from Banning, California, carries
the information that the skull was taken from the stomach of a
_Crotalus_ (rattlesnake).

In reporting on a study of owl predation in Delaware County,
Pennsylvania, Pearson and Pearson (1947:143) mention that "weasels are
found throughout the county but . . . were never eaten by the owls."

The Uinta spermophile at some places and times probably is a prey
sought by the long-tailed weasel but Warren (1924:265) records
_Citellus armatus_ repeatedly chasing weasels in August, at Camp
Roosevelt, Yellowstone National Park, and how the ground squirrels at
one time ignored the weasel even when it came within a few inches of a
squirrel.

Warren (1932:71), on August 2, 1931, at Grand Mesa, Colorado, obtained
a large male weasel with two porcupine quills in it; one was near the
mouth and another "in the skull." Osgood (1935:156) writes that near
Rutland, Vermont, a male weasel "taken in April, was heavily
parasitized and had several short porcupine quills embedded in its
neck, head, and shoulders." The remainder of Osgood's account implies
that the weasel may have turned to porcupine because the normal food
for weasels was scarce at the time. Porcupine quills, then, are a
hazard for weasels although it is unlikely that the porcupine is ever
to be classed as an enemy of the weasel.

An accident of another sort, which must at the very least have been
annoying to the weasel that suffered it, was recorded by Soper
(1921:37). The animal had a stick lodged crosswise between the fourth
upper premolar teeth.

The recorded actions of several kinds of animals which are too small to
be dangerous to the weasel suggest that they recognize that the weasel
is a danger to them. Borell and Ellis (1934:21) mention that a weasel
in Nevada caused a great disturbance among the chipmunks. Long
(1938:250) heard pikas give evidence of terror by a peculiar cry when a
weasel was in a rock slide occupied by the pikas. Seton (1929 (2):629)
writes "On June 14, 1915, as I prowled around the south side of the
lake on my homeland at Greenwich, Conn., my attention was called to a
pair of song sparrows and a male towhee that were noisily mobbing a
Weasel, twittering around and darting at him, as though they knew full
well his evil ways. The weasel paid little heed, but soon dived from
sight in a stone wall."

No account has been found of an American weasel or ermine rolling,
tumbling and frolicking in a manner that aroused the curiosity of birds
to a degree which permitted the weasel to come within leaping distance
of the birds. Accounts of such behavior are on record for the English
stoat (ermine).


Food and Hunting

Weasels are active both in the daytime and at night. Whether the time
of activity varies with the season, with the locality, with the sex or
with other conditions, I do not know. Adult, live, free-living,
actively moving weasels that I recall having seen all were observed in
the daytime: two were in Alameda County, California, two were in White
Pine County, Nevada, one was in Scotts Bluff County, Nebraska, and one
was in Laramie County, Wyoming. I recall ten adults, from the same
three states, and one from Washington State, that got into my traps;
two of these certainly got in the traps in the night; one certainly got
in the trap in the daytime; the other eight were found in traps which
may have caught the weasels either in the night or in the daytime.
Soper (1946:136) in speaking of _M. f. longicauda_ north of the
International Boundary in Canada remarks that it has the "habit to some
extent of hunting at all times of day." Criddle and Criddle (1925:144)
in writing of _Mustela frenata longicauda_ in Manitoba record that "The
shrill cry of a rabbit [_Lepus americanus_] in the dark is nearly
always due to the weasel's attack. Indeed, we have often watched the
latter at work during the twilight hours. First would come the almost
noiseless run of the small rabbit with its characteristic dodging and
this would be followed by the appearance of the agile foe which, at
times, would leap high over obstacles and at others move swiftly
beneath them. Then there would follow intermittent cries of the rabbit
as the weasel secured a temporary hold of its quarry, for be it noted
that this hunter apparently bites anywhere to begin with and it is
probable that the blood made to flow acts as an aid to tracking as well
as weakening the prey. Several similar close encounters might occur
before the rabbit would be finally overcome, but weasels are very
persistent when they once get into contact with their victims and it is
therefore very seldom that the latter escape. In killing, they either
penetrate the brain with their teeth, or dislodge the vertebrae behind
the head." These and more than two score other observations which
record the time when weasels were seen make it clear that some were
active at night and that some were active in the daytime.

As to the routes traveled while the weasels are hunting, Quick
(1944:77) says of four individuals that he studied in Washtenaw County,
Michigan: "The weasels appeared to prefer hunting certain coverts with
noticeable regularity, but rarely cruised the same area on two
consecutive nights."

The killing technique of fifteen captive _Mustela frenata
noveboracensis_ was studied by Glover (1943A). For the weasels he
released 19 mice, 3 brown rats, 6 cottontails and 4 ring-necked
pheasants. Most of the mice were killed by a bite on the back of the
head, with the body and legs of the weasel hugging the back of the
victim. "The weasel shoved the prey in close to the stomach with the
hind legs, and the kill was made in a reclining semi-curled-up
position." On each of the rats (_Rattus_) an initial grip was secured
at the base of the ear. When the rat rested, a new hold was taken by
the weasel. Finally the weasel secured a hold at the base of the skull
and near the ear, and a light crushing sound followed. Four of the six
cottontails were killed by bites on top of the head and ear; two
cottontails succumbed from neck wounds. In three instances, neither of
two weasels could be induced to make a determined attack on the
cottontails or to kill them. At times the cottontails proved to be able
opponents for weasels by striking out with their front feet and by
kicking with their strong hind legs. In killing the pheasants the teeth
of the upper jaw of the weasel pierced the top of the braincase and the
teeth of the lower jaw entered the region of the auditory process. The
forelegs hugged the neck of the pheasant, the body of the weasel was
extended in a riding position on the back of the bird and no amount of
kicking or rolling dislodged the weasel.

Polderboer, Kuhn and Hendrickson (1941) describe a cottontail cached by
a weasel as having the muscles of the neck severed from the region
behind the right mastoid process and noted "that hemorrhage in the
region of the right jugular vein had occurred."

Concerning the methods of killing mammals smaller than cottontails, the
accounts by Nichols and Nichols (1935:297-299) and that by Svihla
(1931) corroborate Glover's (1943A) account, as do also the accounts of
Miller (1931B:164) and Moore (1945:257). The latter says that his
captive male, from Gainesville, Florida, customarily bit its rodent
prey at the base of the skull and used the feet to manipulate the live
prey. Miller (_loc. cit._) emphasized that his male weasel (_M. f.
longicauda_) grasped where it could, used its snakelike body to coil
over the prey and shifted the grip of its teeth to the nape of the neck
or back of the skull. The captives that I have had [one from Salt Lake
City, Utah; three from Contra Costa County, California; and the same
individual reported upon by Miller (1931:150)] customarily employed the
techniques of killing small rodents that were described by Glover and
Miller (_loc. cit._).

Allen (1938:225-229) experimented with the ability of four different
males of _M. f. noveboracensis_ from Michigan to kill adult
cottontails. The method used was to place the weasel in a cage of
quarter-inch hardware cloth approximately three feet long, two feet
wide, and two feet high. The bottom of the box was covered with several
inches of straw. One cottontail was offered to each weasel. In two
instances the weasel attacked and bit the cottontail, was struck by the
hind feet of the cottontail, retired from the attack and died a few
hours later as a result of the blows of the cottontail's hind feet. In
the other two instances the weasel rendered the cottontail helpless by
severing the neck muscles from the skull. Subsequently an incision made
by the weasel, in each of the two instances gave access to blood on
which the weasel fed until it was full, in one instance by licking
"blood as a cat laps milk." One rabbit was subdued in 10 minutes and
the other in 15 minutes. Allen (_op. cit._) points out that cottontails
form a considerable portion of the weasel's food and thinks that they
are killed in burrows more easily than they were in the cage.

In writing of the three species of weasels, including _Mustela
frenata_, found at Treesbank and vicinity, Manitoba, Norman Criddle and
Stuart Criddle (1925:143, 144), in my opinion, correctly explain the
killing of more prey than weasels need. "The fact that weasels
frequently kill many more animals than they require for immediate use
has been universally interpreted as a lust for killing--a supposition
which we believe to be quite erroneous. It is true that weasels often
kill more than they need, but the surplus is not necessarily wasted
because the animals always store it for future use, in much the same
way as do badgers, minks or skunks, and with the same object in view as
squirrels have in gathering nuts. We have observed many such stores,
but as far as our observations go, the habit of killing in excess
occurs much more prominently in the late summer and autumn months than
in the spring. Indeed, we have no records of excessive spring slaughter
and this indicates that the supposedly blood-thirsty habit of weasels
is no more a lust for killing than is the woodsman's foresight in
providing his larder with meat for the winter months. It should be
noted in this connection that members of the weasel family, when
undisturbed, do not leave their victims scattered about, but carefully
store them away, and in many instances the bodies are buried with earth
or taken under ground to preserve them. We suspect that this instinct
for preserving food for future use accounts for most of the excessive
killing by carnivorous animals instead of this latter indicating an
aimless desire for slaughter which would unnecessarily deplete the food
supply of the future. This instinct, however, does not seem to be as
definite as that of some rodents, and there is no doubt that much of
the stored meat decays before it can be utilized."

Criddle and Criddle (1925:146) note that a weasel in the vicinity of
Treesbank was carrying a rat [_Rattus_] and that "Two small punctures
in the throat were the only evidence of the manner in which its death
had been brought about."

Considerable information has been recorded concerning the food of
_Mustela frenata_ and a little information is on record as to kinds of
foods not taken that could have been taken. For example, Ingles
(1939:253, 254) on May 14, 1938, near Shasta City, California, noted
that nestlings of russet-backed thrushes were ignored by an adult
weasel and four young weasels which were feeding instead on meadow mice
and a mole. Howard (1935:322, 323) records that a weasel in Michigan
which carried bits of meat from beef bones on a porch ignored a red
squirrel which drew on the same food supply but which retreated to the
end of the porch when the weasel appeared. Quick (1944) records that in
the winter of 1940 on a 640 acre area in Washtenaw County, Michigan,
four resident weasels did not kill any of the 10 rabbits or several
pheasants but subsisted on smaller animals. Glover (1943A) thought that
_M. frenata_ kills only a few adult cottontails in the wild. To judge
from these observations, _M. frenata_ chooses small mammals as prey in
greater measure than it does birds or larger mammals.

Records of prey taken, attacked or pursued by _Mustela frenata_ include
the following:

Broad-footed mole (_Scapanus latimanus_).--One was fed on by an adult
_M. frenata_ and four young, on May 14, 1939, "near Shasta City,"
California (Ingles, 1939:253, 254).

Dusky shrew (_Sorex cinereus_).--A female weasel, at Majestic, Long
Island, N. Y., was shot when carrying a _Sorex cinereus_ that had a
small hole in the top of its head (Nichols and Nichols, 1935:297-299).

Big short-tailed shrew (_Blarina brevicauda_).--One was taken from the
stomach of a weasel (Hamilton, 1928:249).

Townsend ground squirrel (_Citellus townsendii_).--Alcorn saw a weasel
five miles west of Fallon, Nevada, carrying a squirrel (Hall,
1946:192).

Richardson ground squirrel (_Citellus richardsonii_).--The attempted
capture of one of these squirrels in Saskatchewan is recorded by Seton
(1929 (2):625).

Belding ground squirrel (_Citellus beldingi_).--Grinnell, Dixon and
Linsdale (1937:233) recount that at Tuolumne Meadows, California, a
weasel killed a ground squirrel of this species.

Thirteen-lined ground squirrel (_Citellus
tridecemlineatus_).--Errington (1936:406, 407) found a den in Palo Alto
County, Iowa, on June 22, 1934, where he collected 32 fecal pellets.
Sixteen samples contained thirteen-lined ground squirrels, 9 contained
rabbits, 9 contained mice (7 _Microtus_, 1 _Peromyscus_ and 1
unidentified); red-winged blackbirds and unidentified fringillids were
represented as also were ground beetles, grasshoppers and other
insects. One red-winged blackbird lay near the entrance of the den.

Franklin ground squirrel (_Citellus franklinii_).--Sowls (1948:126)
records that at Delta, Manitoba, a weasel was observed killing one of
these squirrels and that "the weasel had taken the squirrel from its
hibernating burrow as evidenced by tracks in the snow." On July 19,
1917, in the vicinity of Treesbank, Manitoba, T. Criddle saw a weasel
attacking one of these ground squirrels which was in mortal terror and
squeaking continuously. Eventually the squirrel was thrown on its back
"and would have been speedily killed but for an interruption" (Criddle
and Criddle, 1925:146).

Golden-mantled ground squirrel (_Citellus lateralis_).--On August 15,
1941, along the Kaweah River in Sequoia National Park, Boyer (1943:99,
100) saw a weasel chasing a _Citellus lateralis_; three or four times
the weasel grasped the back of the neck of the squirrel which each time
threw off the weasel until the two, weasel after the squirrel, plunged
into the river. The squirrel, bleeding at the base of the skull, was
rescued and entered a hole; the weasel got out of the water and under a
rotting log. Follett (1937:365) at 2 p.m. in Plumas County, California,
saw a weasel have hold of the lower jaw of a golden-mantled ground
squirrel near its throat. Alcorn watched a weasel chase a
golden-mantled ground squirrel in Nevada (Hall, 1946:192) and Grinnell
and Dixon (1919:681) record that on August 4, 1911, near Monache
Meadows in eastern Tulare County, California, a weasel pursued,
captured and killed a golden-mantled ground squirrel.

Eastern chipmunk (_Tamias striatus_).--Pearce (1937:483) in central New
York State, on July 29, 1931, saw a chipmunk scamper up a tree pursued
by a weasel.

Chipmunk (subgenus _Neotamias_).--Stanford (1931:363) on November 11,
1931, at Fish Lake, Utah, saw a weasel pursuing a chipmunk. On August
5, 1910, "near Independence Lake," Nevada County, California, Louise
Kellogg recorded that a weasel seized and ran off with a chipmunk
(Grinnell, Dixon and Linsdale, 1937:233). Allen (1938:228) observed
that a chipmunk (whether _Tamias striatus_ or _T. minimus_ not
specified) was killed in 30 seconds whereas 10 to 15 minutes were
required by the caged, male _Mustela frenata noveboracensis_ to kill a
cottontail.

Red squirrel (_Tamiasciurus_).--Seton (1929 (2):625) records the
capture of one in Pennsylvania, and Grinnell, Dixon and Linsdale
(1937:232), at Cisco, California, saw one closely pursued by a weasel.

Flying squirrel (_Glaucomys_).--Burroughs (1900:77, 78) records remains
of one of these squirrels along with the remains of other animals in a
food cache of a Mustela but his account does not make clear whether
_Mustela frenata_ or _Mustela erminea_ was the species of weasel
involved.

Northern pocket gopher (_Thomomys_).--In "July, 1939, near Stillwater
[Nevada], Alcorn pursued . . . [a] weasel and caused it to drop . . .
a pocket gopher [_Thomomys bottae_] which was about two-thirds grown"
(Hall, 1946:192). Grinnell, Dixon and Linsdale (1937:233) write that
"at least twice, weasels in the [Yosemite] Valley were seen carrying
pocket gophers." Relative to _Thomomys talpoides_ in the vicinity of
Treesbank, Manitoba, Criddle and Criddle (1925:146) record that on
September 11, 1918, an individual of _Mustela frenata longicauda_ took
seven pocket gophers dead. . . . It seized the rodents by the middle of
their back and held them high while carrying them away. They were
stored in a gopher burrow some two hundred yards distant. On February
17, 1921, "Came across the marks of a weasel carting some object over
the snow. An investigation revealed a recently-killed pocket gopher
with its captor still in possession." Criddle (1930:279), at Aweme,
Manitoba, "frequently observed this weasel [_M. f. longicauda_] . . .
carrying a pocket gopher to its larder, and twice it has been
encountered in mid winter with freshly killed gophers in its
possession." The evidence already presented that weasels levy heavily
on pocket gophers is strengthened by the many references in the
literature to weasels having been caught in traps set for pocket
gophers in the burrows of those rodents and by the many statements, not
quoted here, that living quarters of weasels are in burrows made
originally by pocket gophers. For example, the present writer, in an
account of the Mammals of Nevada (Hall, 1946:191, 192), has said of the
long-tailed weasel, _Mustela frenata nevadensis_, that "All the three
dens that were excavated . . . were originally burrows of pocket
gophers. . . . Although we have found weasels in many situations in
Nevada, . . . they most often were obtained from the burrows of pocket
gophers." Excluding the weasels taken by Alcorn, more specimens of the
remaining lot were caught in traps set in the burrows of pocket gophers
than by all other means combined. All of the 22 weasels taken by Alcorn
[within a radius of 10 miles of Fallon] were obtained in gopher traps.

Mexican pocket gopher (_Cratogeomys_).--At Chalchicomula, 8000 feet,
Puebla, Nelson (1918:470 and letter dated March 9, 1928) saw a weasel
fastened to a pocket gopher. Nelson obtained the pocket gopher and
found that its neck muscles were torn loose from the skull.

Grasshopper mouse (_Onychomys_).--Barber and Cockerell (1898:189) found
remains of this mouse in the stomach of a weasel at Mesilla Park, New
Mexico.

White-footed mice (_Peromyscus_).--Green (1936) saw a weasel in Gratiot
County, Michigan, in May, carrying a _Peromyscus_. Quick (1944:76), in
winter, in Michigan, found one dead, probably killed by a weasel. From
Washtenaw County, Michigan, Quick (1944:77) examined 294 scats of
free-living weasels and found _Peromyscus_ in 189 scats, _Microtus_ in
83, small birds in 20, red squirrel in 3, and hair of weasels in small
quantities (probably from the animals which deposited the scats) in 36.
He concludes (_op. cit._, 78) that the winter food was 65 to 70 per
cent _Peromyscus_, 23 to 33 per cent _Microtus_, and 2 to 7 per cent
small birds.

Wood rats (_Neotoma_).--A female long-tailed weasel weighing 250 grams
was taken one mile north of Kent, Texas, while eating a _Neotoma
albigula_ (Davis and Robertson, 1944:263). A wood rat house under
observation by Vestal (1937:364) in Contra Costa County, California,
was invaded by one weasel which ate two adult wood rats (_Neotoma
fuscipes_) and one young. In the same area he saw a weasel in a wood
rat nest some months later (Vestal, 1938:5). Three miles east of Reno,
Nevada, on May 13, 1936, W. B. Richardson watched a long-tailed weasel
carrying a half-grown round-tailed wood rat (_Neotoma lepida_) across a
rock slide (Hall, 1946, 192). Harper (1927:303) records three wood rats
[_Neotoma floridana_] and two cotton rats [_Sigmodon hispidus_] found
dead in the den of a female weasel and her three young in the
Okefinokee Swamp of Georgia. Another female and three young
approximately half grown were found in the swamp in a hollow pine log.
Contents of the den as described to Harper were nearly a peck of wood
rats, whole and in pieces; remains of several kinds of birds including
robins and quail, and a piece of joint snake (_Ophisaurus ventralis_).

Meadow mice (_Microtus_).--Polderboer, Kuhn and Hendrickson (1941), in
1939, at Ames, Iowa, identified "A total of 118 items . . . in 97
winter scats and 48 in the 38 spring scats." Their combined data are as
follows:

                          Frequency      Percentage
  Meadow mouse               71            42.85
  Harvest mouse              36            21.75
  Deer mouse                 17            10.23
  Mearns cottontail          14             8.42
  Short-tailed shrew          9             5.42
  House mouse                 3             1.86
  Tree sparrow                2             1.02
  Grasshopper                 1              .60
  Shaw pocket gopher          1              .60
  Least weasel                9             5.40
  Unidentified material       3             1.85

Polderboer, Kuhn and Hendrickson divide their data into two categories,
winter and spring. Items recorded in winter but not in spring are house
mouse, tree sparrow, and grasshopper. Items recorded only in spring
were pocket gopher and least weasel. The samples of cottontail and
least weasel all were from the scats of one large male weasel. Of a
total of 14 pheasants, 24 quail and 35 cottontails on the 160 acres
involved in the study only two cottontails appear to have been killed
by the weasels--really by one weasel of four which lived on the area.

Food items taken from the nests (3) and adjacent caches of food in the
dens, were as follows: meadow mouse, 30; short-tailed shrew, 4; pocket
gopher, 2; deer mouse, 2; least weasel, 1; tree sparrow, 1. The authors
remark that the abundance of several prey species does not cause the
weasels to ignore the shrews which are said to be distasteful to
carnivores.

Two horned larks, apparently killed by weasels, were found on the 160
acre area studied; the horned larks were not in caches of food, nor
were remains of horned larks found in scats.

Dearborn (1932:34, 37) for Michigan, on the basis of contents of (37?)
intestinal tracts and "feces collected partly in winter and partly in
summer" found that, by frequency of occurrence, mammals comprised 83
per cent of the food, birds 10 per cent and insects 7 per cent.
Frequency indices for the genera of mammals in percentages of food
items of all kinds were as follows: _Microtus_, 31 per cent;
_Peromyscus_, 24 per cent; _Sylvilagus_, 14 per cent; _Sorex_, 7 per
cent; _Blarina_, 5 per cent; _Scalopus_, 2 per cent.

Criddle and Criddle (1925:146), for the vicinity of Treesbank,
Manitoba, record that on October 3, 1913, a weasel was seen to take a
field mouse down a hole. They add (_op. cit._: 147) that "Once while
ploughing, we observed a Long-tailed Weasel carrying a field
mouse. . . ." Ingles (1939:253, 254), in June, 1938, near Mt. Shasta
City, California, found an adult and four young weasels which fed on
several _Microtus montanus montanus_. Green (1936) in May, in Gratiot
County, Michigan, in the vicinity of a nest in which there were four
young weasels, found "several" dead _Microtus_. Hamilton (1933:330)
records that in New York State a male weasel, on April 5, 1932, at
Ithaca, had eaten a _Microtus_ and that in May, 1927, a female weasel
was seen carrying a _Microtus_ in its mouth.

Hamilton's (1933:333) study of the contents of the digestive tracts of
bodies of weasels obtained from fur trappers and fur buyers enabled him
to publish the following "Frequency Indices of Mammal Genera in Fall
and Winter Food of 163 _Mustela noveboracensis_": _Microtus_, 33.6 per
cent; _Sylvilagus_, 17.3; mammals undetermined to genus but principally
mice, 17.1; _Peromyscus_, 11.3; _Rattus_, 9.1; _Blarina_, 5.9;
_Sciurus_, 2.7; _Tamias_, 1.0; _Condylura_, 0.8; _Ondatra_, 0.8.

Grinnell, Dixon and Linsdale (1937:233, 234) quote W. Fry concerning a
weasel which reared six young at Giant Forest, California, in 1919, as
follows: "This parent weasel, after the birth of her young, remained at
the premises for a period of thirty-seven days; during which time, from
actual count, the following numbers of mammal species fell victim to
her: mice [genera not specified] 78; gophers 27; moles 2; chipmunks 34;
wood rats 3; ground squirrels 4. This is a total of 148 animals for
the . . . thirty-seven days . . . not a bird was captured during the
period."

Rats (_Rattus_).--Criddle and Criddle (1925:146), on the farm at
Treesbank, Manitoba, record a long-tailed weasel, on July 2, 1918,
running away from the farm buildings carrying a rat; July 11, 1919,
"Two _longicaudas_ . . . have been seen running off with rats on
several occasions."; July 11, 1920, "There are two large weasels about
the buildings[;]. . . . Each has been noted with rats and this
afternoon one of them was seen running into the woods carrying a rat,
followed by two excited swallows." The authors (_op. cit._:147) add "In
the fall of 1924, Mr. A. Cooper, a prominent poultryman of Treesbank,
observed a large weasel carrying a freshly killed rat which it stored
below ground and then returned towards the poultry-house, causing no
little apprehension to the owner. Within a short time, however, the
weasel reappeared with another rat which it hid as before. In this way
several rodents were accounted for during the afternoon, and Mr. Cooper
assures us that the weasel 'kept up the good work for some days'."
Hamilton (1933:330) in New York State in May, 1927, saw a male weasel
in possession of a rat.

Big jumping mouse (_Zapus major_).--In the Warner Mountains of
California, on Parker Creek, H. C. Bryant frightened a weasel that
dropped a freshly killed jumping mouse (Grinnell, Dixon and Linsdale,
1937:232).

Snowshoe rabbit (_Lepus americanus_).--Adolph Murie (1935:321-322)
writes that: "Four miles north of Funkley, Minnesota, early on the
morning of November 13, 1921, . . . watched from the top of a 30-foot
spruce a weasel. .. hunting a varying hare. . . . The ground was
covered with six inches of fresh snow . . . both animals . . . [had]
their [white] winter pelage.

"My attention was first attracted to the hare as it came hopping
steadily but unhurriedly from the north. Directly in front of me, about
75 feet from the tree I had climbed, the hare crisscrossed back and
forth at various angles over an open area about 20 feet in diameter.
After producing a maze of tracks, the hare 'froze' near one edge of the
pattern. In a few minutes the weasel appeared, all his faculties
focused on the warm trail. Expertly he followed its convolutions,
passing at times within a few feet of the watching hare. Not until the
weasel had followed every turn of the trail to within three feet of its
termination did the hare skip off. It came out to the road almost
directly below me, turned at right angles northward and was soon out of
sight. At the road the weasel lost the trail, . . . and then ran
parallel with it, once more in hot pursuit.

"Ten minutes later the hare emerged from the north as before, came on
directly to the tracked-up area, and continuing its stratagem,
leisurely hopped about to leave its zigzag trail. Then it sat down
quietly to wait. . . . The weasel['s] . . . nose led him through the
network with little trouble. He was almost upon the hare before it
jumped off and followed the same path [as] . . . before. . . .

"The hare had to show his big heels [a third time] . . . as the weasel
approached him. This time the weasel failed to follow. . . . After
examining a few brush heaps he vanished into the woods behind me."

Seton (1929 (4):723, 724) writes that in December of 1886 in the
sandhills northeast of Carberry, Manitoba, he saw a weasel chasing a
snowshoe rabbit which took refuge near his feet under the sleigh and so
escaped the weasel. Thurber (1940:356) mentions a month-old varying
hare that was rescued from a weasel and of approximately the same size
as the weasel.

Criddle and Criddle (1925:146) for the vicinity of Treesbank, Manitoba,
record "August 21, 1921.--Heard cries of a small rabbit at dusk
to-night, which investigation showed was being attacked by a large
weasel. The rabbit was later carried to the weasel's store chamber
below ground." They record further (_op. cit._, 146, 147): "November 8,
1924.--Shot a bush rabbit and left it lying. Two hours later [it] . . .
was found to have been dragged beneath a brush pile and partly eaten.
Innumerable weasel tracks left no doubt as to the identity of the
thief." In describing a weasel that wintered in a nest in a threshing
machine, the same authors (_op. cit._:143) say that no bird remains
were found in the pile of approximately three pounds of droppings
adjacent to the nest. In a store chamber some 140 yards away from the
nest, two bush rabbits (_Lepus americanus_) had been dragged to the
entrance and numerous smaller rodents were taken below ground. The
rabbits were buried beneath the snow and eaten as necessity arose.
Narrow selectivity on the part of the weasel in choosing food is almost
always shown in instances where the food of weasels has been studied.
For example, the weasel which lived in the threshing machine ate
rodents and rabbits and not poultry although the weasel had ready
access to the poultry building. The weasel which lived in the bag of
feathers in the basement of Stuart Criddle's house ignored grouse,
approximately 20 in number, in favor of other non-avian food.

Cottontail (_Sylvilagus_).--Polderboer, Kuhn and Hendrickson (1941)
mention that one of 4 weasels which they studied on a 160 acre area at
Ames, Iowa, in 1939, had a cache of food in a pocket gopher burrow 10
rods distant from the weasel's den. The cache contained only two
cottontails, one partly eaten. Leopold (1937) records seeing a
_Mustela_ (probably a long-tailed weasel but possibly an ermine) kill a
third-grown cottontail by biting it at the base of the skull. Leopold
describes the blood sucking or licking, suggesting that he shared the
popular misconception that weasels suck blood. The supposition that
weasels suck blood has been refuted by many observers, for example by
Svihla (1931). My own observation of captives makes me think that
weasels do not suck blood. Seton (1929 (2):626) quotes B. H. Warren as
seeing a weasel dragging a freshly killed, still warm, rabbit that
contained nine embryos almost ready for birth. A young rabbit was seen
being carried by a weasel in Hidalgo County, Texas, in March, 1935
(Mulaik, 1938:104). An instance of a cottontail being chased in June in
South Carolina is recorded by Hamilton (1933:330). Addy (1939:372,
373), in Virginia, on August 14, 1939, shot a large weasel which was
pursuing a _Sylvilagus_ that was only a foot and a half ahead of the
weasel. The rabbit stopped when a shot was fired and permitted itself
to be stroked and petted. Tracking showed that the weasel had chased
the rabbit for a half mile. On November 20, 1942, at Lake James,
Indiana, a weasel was seen by Grosjean (1942:443) attacking a "young
rabbit" in the throat of which the weasel had made five large holes
from which there was no obvious bleeding. Seton (1929 (4):798) recounts
that in 1910 at Base Lake, Michigan, F. C. Hicks saw a cottontail with
a weasel hanging to its legs rush to the cottage. When only four feet
from Hicks the weasel loosed its hold and the cottontail escaped under
the cottage. Burroughs (1939:253) on May 14, 1939, in Saginaw County,
Michigan, records that a young cottontail weighing between 200 and 250
grams was carried from the nest and killed. Burroughs was attracted
first by the "hissing scream" of the weasel, strode toward the sound,
flushed an adult cottontail, and discovered the empty nest from which
the weasel had taken the young cottontail.

Brush rabbit (_Sylvilagus bachmani_).--Vestal (1937:364) in Contra
Costa County, California, found a brush rabbit that appeared to have
been killed by a weasel.

Reptiles.--Grinnell, Dixon and Linsdale (1937:234) recount that in
July, 1889, in Wilson Canyon, near Pasadena, California, a weasel
killed a red racer by severing the backbone of the snake. In April,
1935, in Hidalgo County, Texas, a half grown bull snake (_Pituophis
sayi sayi_) was regurgitated by a young weasel. Russell (1930:504, 505)
has recorded finding in California a male weasel and a king snake
(Lampropeltis getulus boylii) three feet five inches long in mortal
combat. The weasel killed the snake but the weasel, incapacitated by
the conflict, was easily picked up by hand and was also saved as a
specimen.

Wild birds.--In the spring of 1940, in Washtenaw County, Michigan, one
bobwhite, of 10 bobwhite living on a 640 acre area, was killed by one
of four weasels that lived on the area. No other quail was killed
there. The one unfortunate bird was killed in the mouth of an abandoned
den where the quail roosted (Quick, 1944:76). A male weasel, subspecies
_M. f. effera_, was seen by Booth (1946:439) attempting to enter the
nesting hole of a pair of flickers, _Colaptes_. One song sparrow
(_Melospiza melodia_), and one slate-colored junco (_Junco hyemalis_)
were recorded by Quick (1944:76) as killed by weasel in Michigan.

Chicken (genus _Gallus_).--Quick (1944:78) writes that in one year
(1938-1939) weasels were reported to have killed 1.03 per cent of all
chickens in one township of Washtenaw County, Michigan, and that of the
total damage to all kinds of poultry, 59 per cent was done by weasels.
Weasels entered 19 per cent of the chicken coops on the study area.
Farmers killed 68 per cent of the weasels seen in barn yards. Spring
and summer were the seasons in which most of the weasels were observed
in barn yards. Internal evidence in Quick's (_op. cit._) account leads
me to suspect that some losses of poultry were charged to weasels when
_Rattus_ was actually responsible.

Criddle and Criddle (1925:146), quote a neighbor in the vicinity of
Treesbank, Manitoba, as recording that on October 29, 1917, "A weasel
last night made its way into our fowl-house, the door being
inadvertently left open. The weasel killed eleven fowl, some of which
were dragged into the yard. All the largest fowls were selected, the
pullets remaining untouched though they were in the majority. Next
night the weasel dug a hole beneath the building and killed a hen and
two cocks, returning for another during the day, making a total of
fourteen in all." Criddle and Criddle (1925:146) remark that the weasel
proved to be a large one, probably an old male. The same authors (_op.
cit._:147) record that at their farm at Treesbank, Manitoba, on January
31, 1925, "A Long-tailed Weasel killed three hens last night, and
rather severely bit a cock about the neck. This, or another weasel, had
been around the farm-yard for sometime (The specimen was a large
male). . . .

"In the fall of 1924, Mr. A. Cooper, a prominent poultryman of
Treesbank, observed a large weasel carrying a freshly killed rat which
it stored below ground and then returned towards the poultry-house,
causing no little apprehension to the owner. Within a short time,
however, the weasel reappeared with another rat which it hid as before.
In this way several rodents were accounted for during the afternoon,
and Mr. Cooper assures us that the weasel 'kept up the good work for
same days'.

"Being a farmer of many years' standing, Mr. Cooper has naturally lost
some poultry through the agency of weasels, but while he remarks that
'there are good as well as bad actors among weasels', he has the
practical good sense to recognize the value of an efficient ratter even
though it be a weasel.

"Our sister, Maida Criddle, writes under date of March 4, 1925:

"'There is another weasel (_longicauda_) in the fowl-house, a
well-behaved one this time. It came and took a piece of meat out of my
hand quite nicely, which it carried down a hole and then came and
sniffed all over my mitt to see if there was any more. I thought it had
been killed when I visited the farm buildings next day as there was a
strong smell of musk on the cat and in the fowl house, but the weasel
was there as cheeky as ever. It got hold of my skirt twice and tried to
pull me down its hole. I think it wanted the cloth for a bed, as it was
taking straw and other material down the burrow. The poultry were very
frightened at first, but they are getting used to the weasel's presence
now'."

In commenting on the economic role of the long-tailed weasel in
Manitoba, Criddle and Criddle (1925:145) write as follows: "Supply and
demand are prominent factors in governing our weasels' food habits. The
two smaller species, as we have already pointed out are so dependent
upon mice for a living that they increase or diminish with the
fluctuation of these creatures. The Long-tailed Weasel, however, is not
so easily checked by the temporary disappearance of any particular kind
of game. If mice are scarce it devotes greater attention to gophers or
bush rabbits and if these are not in sufficient numbers to satisfy its
appetite, the animal raids a poultry house as a last resource. In nine
years out of ten, this weasel will find sufficient food about the
fields and woods, but on the tenth it may be obliged to temporarily
turn to domestic animals. It is at such times that the weasel is seen
and its deeds recorded. A thousand mice may have been killed in the
meantime, but the destruction of half a dozen hens is alone used as
evidence of the weasel's economic standing.

"In the last twenty years we have permitted weasels to frequent the
farm buildings at will and the poultry house has been no exception. In
that time rats and mice suffered severely from the weasels, while the
total number of poultry taken were six. Many times that number,
however, have been killed by rats.

"When we review our experiences of the past, we are astonished to find
what few poultry have been killed by weasels. Our own losses in
forty-two years have not exceeded fifteen birds and even these were
usually eatable. There have been reports of losses from time to time
from neighbors, but on looking into details we find that there are very
few farmers who have experienced more than three separate occasions of
weasel depredation and the total loss per farmer in the last thirty
years does not, we are sure, exceed ten birds. This is surely a
remarkably small payment to weasels in general for the great good done
by them in killing rodents.

"We wish to point out, too, that only the exceptional weasel becomes a
poultry killer. In most cases apparently it is a fully-grown male that
does the killing. There are exceptions, of course, but when we see a
large weasel actively engaged in rodent hunting within a few feet of a
brood of newly hatched chickens and not even looking at them, we must
at least pause to ask if this animal is the enemy that we were taught
to believe it to be."

A suggestion that weasels sometimes obtain the prey killed by hawks is
offered by Criddle and Criddle (1925:147) who write: "Hawks are not
always the aggressors, as is shown by an incident reported by Mr. H.
L. Seamans, of Lethbridge, Alberta. Mr. Seamans noted a large buzzard
suddenly fly straight upwards from a fence post, and then alight upon
another one some distance away. A little while afterward this bird once
more arose in the same manner as before, and presently repeated the
performance again. An investigation then followed and revealed that a
Long-tailed Weasel was following the hawk from post to post.

"We should hardly expect a weasel to attempt to capture a bird of the
above type. On the other hand, it is possible that these animals might
be able to startle a hawk sufficiently to cause it to drop its prey,
which would thus provide food for the weasel."

The following frequency index is compiled from the foregoing data on
prey of _Mustela frenata_.

  Moles (family _Talpidae_), 5
  Shrews (family _Soricidae_), 26
  Pigmy weasel (_Mustela rixosa_), 1
  Ground squirrels (genus _Citellus_), 23
  Chipmunks (genus _Tamias_), 38
  Tree squirrel (possibly all _Tamiasciurus_), 8
  Flying squirrel (genus _Glaucomys_), 1
  Pocket gophers (family _Geomyidae_), 34
  Mice (order _Rodentia_), 96
  Harvest mice (genus _Reithrodontomys_), 36
  Grasshopper mouse (genus _Onychomys_), 1
  Deer mice (genus _Peromyscus_), 235
  Cotton rat (genus _Sigmodon_), 2
  Wood rats (genus _Neotoma_), 14
  Meadow mice (genus _Microtus_), 248
  Muskrat (genus _Ondatra_), 1
  Old World rats (genus _Rattus_), 19
  House mouse (genus _Mus_), 1
  Jumping mouse (genus _Zapus_), 5
  Varying hare (_Lepus americanus_), 5
  Rabbits (genus _Sylvilagus_), 48
  small birds, 32
  chickens, 17
  lizard, 1
  snakes, 4
  insects, 3

More significant than the above compilation, of course, are the results
of careful studies of the food of the long-tailed weasel in restricted
areas. Examples of such studies are those of Polderboer, Kuhn and
Hendrickson (1941) and Hamilton (1933:333).

According to Hamilton's (1933:332) observations on captive weasels,
"There seems to be little relative difference in the amount they eat,
regardless of their activities.

"In general, more food is taken in summer than in winter. Usually about
a third their weight every 24 hours is eaten, but a growing young
weasel will consume much more. A young male _noveboracensis_, weighing
145 grams, consumed an entire chipmunk, fur and bones, weighing 85
grams, in 24 hours. A day later it ate all of a partly grown rat, 105
grams, in the same length of time."

Moore (1945:253) records that a captive male that he obtained at
Gainesville, Florida, consumed, on the average, between 63 and 70 grams
of flesh and blood per day. The weasel itself weighed approximately 320
grams.

Sanderson (1949:413), concerning seven young weasels from Manitoba,
that he raised in captivity, writes: "From the fifth to the seventh
week of age, they consumed approximately 22 per cent of their body
weight per day; from the eighth to the tenth week (just before reaching
mature size) they consumed approximately 24 per cent; but after
reaching maturity they consumed only 18 per cent. When given all the
food they would take in one day, they ate as much as 40 per cent of
their body weight."

Criddle and Criddle (1925:143, 146) say that weasels drinking at a bird
trough "held their mouths very close to the water and as far as we
could see, lapped the liquid up with rapid movements of the tongue. As
a rule, after drinking, they would merely spring to the ground and
vanish amid a bunch of scolding birds, but occasionally we have seen an
animal slowly drag itself through the water and follow this performance
by some rapid gambols, or a quick run, a method of drying which most of
us have practiced in our youth." According to Hamilton's (1933:332)
observations on captives, "Weasels are great drinkers, and while they
take but little at a time, about 25 c.c. is drunk by a large animal
during a day. . . ."


Reproduction

Philip L. Wright's several papers (1942A, 1942B, 1947, 1948A, and
1948B) reporting on his detailed studies of _Mustela frenata_
(subspecies _oribasus_ and _longicauda_) in captivity have yielded a
large share of the precise information that we have concerning breeding
and reproduction in this species. He has found that a single litter, of
up to 9 young is born in the spring, usually in April. At three months
of age the females "are full grown." The young males remain sexually
immature during the first summer but the young females, as well as the
females which are more than a year old, come into heat in the midsummer
and are bred by the adult males. After a long period of quiescence
lasting for several months, the embryos resulting from these matings
become active in early spring and develop to full term in less than 27
days after they become implanted. The adult males are sexually active
from April into August, when the testes are at maximal size and are
conspicuous in the scrotum. A gradual regression takes place starting
in August and extending into September. By October the testes may be
fully regressed and the molt to white may start in this month. The
white winter weasel, of either sex, is sexually inactive. The testes of
the sexually active male in early spring and late summer are seven to
eight times the size of the fully regressed testes. Females which had
borne and suckled young were first found to be in oestrus 65 to 104
days after birth of the young. Lactation lasts for approximately 5
weeks. In 18 litters the length of the gestation period varied from 220
to 337 days with an average of 279 days. The female in heat has the
vulva much swollen and she will remain in this condition for several
weeks if not bred. Wright (1948A) describes the actual mating as
beginning with a scuffle after which the male grabs the female by the
scruff of the neck with his teeth and holds her until she becomes
subdued when he clasps her lower abdomen with his front feet and arches
his back over her posterior regions. The two animals remain locked in
this position usually for two hours and sometimes for longer than three
hours. If the animals are left together, copulation may take place
again on the same day or upon succeeding days.

Hamilton (1933:316-321) writes of a freshly born _M. f. noveboracensis_
that it ". . . was pink and much wrinkled. The wetness . . . did not
entirely obscure a few sparse, rather long, white hairs . . . over its
back and head. It had the pronounced and extraordinarily long neck of
the adult." At one day of age the average weight of six individuals in
the litter was 3.1 grams, which is 3 per cent of the weight of the
adult female and 1-1/2 per cent of the weight of an adult male. At two
weeks of age "The silky white hair . . . obscures the general flesh
color of the skin, evident a week earlier. The hair on the back of the
head and neck, also over the shoulders, is slightly longer than that of
the back . . ." but there is no crest or mane or pompadour at this or
any other age such as characterizes the juvenal ermine. When 21 days
old one young male "hurried from the nest chamber and commenced to eat
some meat." At three and a half weeks "They are all eating small pieces
of meat. . . . The canine teeth have made their appearance in both the
upper and lower jaw, but just a hint of the incisors show. Some of the
cheek teeth are through, as the meat appears to be thoroughly
masticated by the little ones." On the 36th and 37th days the eyes
opened. Sanderson (1949:415) found that a litter of seven young of
_Mustela frenata longicauda_, from Manitoba, raised in captivity,
"reached the peak of their growth" at approximately ten weeks of age.

Several nests have been found. In Manitoba, Sanderson (1949:412)
excavated a burrow at the mouth of which he had trapped the adult
female and in which he found eight young approximately five weeks old.
The "burrow was about three inches in diameter, with two chambers at a
depth of twelve inches. One of these was empty, the other contained the
young. The two surface-openings were but two feet apart and the entire
burrow was no more than three feet long. . . . The meager nest
material consisted entirely of finely chopped grass. There was no mouse
hair present, no accumulation of fecal material, and no storehouse
containing food."

Charles O. Handley has written me that on January 25, 1929, on the
Sinkola Plantation, Thomas County, Georgia, he investigated the living
quarters of a family of five weasels, four of which had been shot five
days before by a hunter. According to the hunter each of the four which
had been killed was approximately two-thirds the size of one which
escaped into a hole in the ground. Handley found that the weasels had
been using as headquarters a burrow in the trunk of an old uprooted oak
as well as a nearby gopher burrow. The burrow in the oak was
approximately ten feet long and had been excavated in the rotten wood.
In a distance of fifty feet along the gopher tunnel there were several
used openings with pathways leading away from each. On February 6,
Handley, with the help of a friend, trapped a large male weasel near
this place.

Criddle and Criddle (1925:143) describe a female which, one winter,
slept in a bag of feathers in a basement of a house occupied by one of
the authors; another weasel in winter made its headquarters in a
threshing machine. The nest of the latter "was somewhat roughly
constructed and consisted of a convenient bunch of straw and chaff
under the cylinder."

Harper (1927:303) in the Okefinokee Swamp of Georgia dislodged a weasel
from the house of a wood rat and was told of a den found in the swamp
"in the trunk of a hollow cypress tree" from which a mother weasel and
three young "about the size of mice" were obtained. "The bed contained,
I suppose, a bushel or more of rabbit hair, rat hair, and squirrel
hair. It looked like it must have been used as a den for several years,
although there was no stink that I could detect except the musk from
the old Weasel." Another female and three young approximately half
grown were found in a hollow pine log.

Between January 6 and April 12, 1940, on 640 acres of land, in
Washtenaw County, Michigan, four weasels were studied and each weasel
used only one den in this period (Quick, 1944:78). Criddle (1930:279)
remarks that _M. f. longicauda_ at Aweme, Manitoba, often makes its
temporary headquarters in the burrows of pocket gophers (_Thomomys_). A
female and three young weasels were found by Shaw (1921:167) using a
nest of a mountain beaver in the burrow of that animal. Green (1936),
in May, in Gratiot County, Michigan, saw a weasel enter a hole under a
decayed log and investigated finding four young weasels in a nest
mostly of _Microtus_ fur.

In the early part (winter and spring) of 1939, at Ames, Iowa,
Polderboer, Kuhn and Hendrickson (1941) studied four weasels living in
four separate dens on 160 acres typical of Iowa farmland and excavated
three of the dens. One den was in a weed patch in an old mole run. The
nest chamber, approximately nine inches in diameter and six inches
below the surface of the ground "was filled with grasses packed in a
layer-like formation. In the center of this mass was a nest hollow
lined with patches of mouse and shrew fur. Beneath this layer of fur
and at the sides of the nest were skins, various bones, and skulls of
partially eaten mice and shrews . . . scats [were in the nest]. . . .
At intervals, layers of clean grass had been laid over the filth of the
former bed, thus giving the nest a stratified appearance." A second
den, of a large male, was in a field of sweet clover two feet high in
the former burrow of a Franklin's ground squirrel. The nest cell, seven
inches in diameter and nine inches below the surface of the ground,
"was lined with grasses mixed with much rabbit and mouse fur. Some
scats, and bones and fur of mice and shrews were matted together in
layers at the bottom of the nest." When this den was abandoned the male
weasel occupied, for a month, another burrow, 20 rods distant, of a
Franklin ground squirrel, in the field of sweet clover. The nest cell
measured 11 by nine inches and was 11 inches below the surface of the
ground. "Two nest layers were present. The first, composed chiefly of
coarse straw and grass, had apparently been occupied at some time by a
spotted skunk. . . . On top of the skunk nest was the weasel nest
composed of fine grasses, mouse fur, and skeletal remains of mice."


Relation of the Sexes to each other and to the young

Quick (1944:75) writes that on March 28, in Michigan, he found the
tracks of a male and those of a smaller animal, supposedly a female,
meeting. The two "then led along the fence for about 18 chains and both
entered the den of the male. . . . Only the tracks of the smaller
weasel left the den on the same date. Observation on April 12 showed
that the large male still occupied the den." I am at a loss to explain
this behavior since breeding would not be expected to occur in late
March and since I suppose that the male and female do not live
together except in the breeding season. Consequently, I wonder if the
sign was wrongly read.

[Illustration: FIG. 29. Map showing the geographic ranges of the
subspecies of _Mustela frenata_ and _Mustela africana_.

   1. _M. f. noveboracensis_
   2. _M. f. occisor_
   3. _M. f. primulina_
   4. _M. f. arthuri_
   5. _M. f. olivacea_
   6. _M. f. peninsulae_
   7. _M. f. spadix_
   8. _M. f. longicauda_
   9. _M. f. oribasus_
  10. _M. f. alleni_
  11. _M. f. arizonensis_
  12. _M. f. nevadensis_
  13. _M. f. effera_
  14. _M. f. washingtoni_
  15. _M. f. saturata_
  16. _M. f. altifrontalis_
  17. _M. f. oregonensis_
  18. _M. f. munda_
  19. _M. f. xanthogenys_
  20. _M. f. nigriauris_
  21. _M. f. latirostra_
  22. _M. f. pulchra_
  23. _M. f. inyoensis_
  24. _M. f. neomexicana_
  25. _M. f. texensis_
  26. _M. f. frenata_
  27. _M. f. leucoparia_
  28. _M. f. perotae_
  29. _M. f. macrophonius_
  30. _M. f. goldmani_
  31. _M. f. tropicalis_
  32. _M. f. perda_
  33. _M. f. nicaraguae_
  34. _M. f. costaricensis_
  35. _M. f. panamensis_
  36. _M. f. meridana_
  37. _M. f. affinis_
  38. _M. f. aureoventris_
  39. _M. f. helleri_
  40. _M. f. macrura_
  41. _M. f. agilis_
  42. _M. f. boliviensis_
  43. _M. a. africana_
  44. _M. a. stolzmanni_

Hamilton (1933:328), however, writes that _M. f. noveboracensis_ is to
"be found in pairs when caring for the young. During mid-May, 1927, I
several times saw a male of this species carrying food to a den of
young ones." Green (1936), in May in Gratiot County, Michigan, remarks
that while he was uncovering and examining a nest of four young
weasels, two adults ran about excitedly and one removed a young weasel.
In instances where several nearly full-grown young have been obtained
from one den it has been my experience (Hall, 1946:191) that the only
adult trapped there was the female; no adult male was found or in the
one instance when found he was living alone in a den 200 yards away
from the den of the female and her young. Data are too few to warrant a
definite conclusion about the extent to which the male aids in rearing
the young, but I have wondered if he might not do so when the young
were less than half grown and then live alone when they were more than
half grown.


=Mustela frenata noveboracensis= (Emmons)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

    _Putorius Noveboracensis_ Emmons, Quadrupeds of Massachusetts, p.
      45, 1840.

    _Mustela fusca_ DeKay, Zool. of New York, Pt. 1, Mammalia, p. 34,
      1842.

    _Putorius fuscus_ Audubon and Bachman, Journ. Acad. Nat. Sci.
      Philadelphia, 8 (Pt. 2):288, 1842; Audubon and Bachman, Vivip.
      quadrupeds of N. Amer., 3:234, pl. 148, 1853 (pl. 1848).

    _Putorius noveboracensis_, DeKay, Zool. of New York, Pt. 1,
      Mammalia, p. 34, 1842; Baird, Mamm. N. Amer., p. 166, 1858;
      Merriam, N. Amer. Fauna, 11:16, pl. 4, figs. 1, 1a, 2, 2a, pl. 5,
      figs. 3, 3a, text figs. 4-6, 30, June 30, 1896; Bangs, Proc.
      Biol. Soc. Washington, 10:13, pl. 1, figs. 2, 2a, pl. 2, figs. 2,
      2a, and pl. 3, figs. 3, 3a, February 25, 1896; Cory, Mamm.
      Illinois and Wisconsin, p. 366, plates, 1912.

    _Putorius erminea_, Audubon and Bachman, Vivip. quadrupeds of N.
      Amer., 2:56, pl. 59, 1851.

    _Putorius agilis_ Audubon and Bachman, Vivip. quadrupeds of N.
      Amer., 3:184, pl. 140, 1853.

    _Putorius richardsonii_, Baird, Mamm. N. Amer., p. 164, 1858
      (part).

    _Putorius_ (_Gale_) _erminea_, Coues, Fur-bearing animals, p. 109,
      1877 (part).

    _Putorius noveboracensis notius_ Bangs, Proc. New England Zool.
      Club, 1:53, June 9, 1899. Type from Weaverville, Buncombe County,
      North Carolina.

    _Mustela noveboracensis noveboracensis_, Miller, U. S. Nat. Mus.
      Bull., 79:97, December 12, 1912; Soper, Journ. Mamm., 4:251,
      November 1, 1923.

    _Mustela cicognanii_, Henninger, Journ. Mamm., 2:239, November 29,
      1921; Seton, Lives of game animals, 2:584, 1929 (part, Ohio);
      Hamilton, Amer. Midland Nat., 14:290, July, 1933 (part, Ohio);
      Lyon, Amer. Midland Nat., 17:109, January, 1936 (part, Ohio).

    _Mustela noveboracensis_, Jackson, Journ. Mamm., 3:15, February 8,
      1922.

    _Mustela frenata noveboracensis_, Hall, Carnegie Instit. Washington
      Publ. 473:104, November 20, 1936; Hall, Amer. Midland Nat.,
      18:304, March, 1937.

     _Type._--Williamstown, Berkshire County, Massachusetts. Type
     specimen not known to be in existence.

     _Range._--Altitudinally, sea level to highest parts of mountains
     of eastern United States; Canadian Life-zone of Ontario and Quebec
     southward through eastern United States in Canadian, Transition
     and Upper Austral life-zones to and including upper edge of Lower
     Austral Life-zone in the Carolinas and northern parts of Georgia,
     Alabama, and Mississippi; westward from the Atlantic Coast to St.
     Croix and Mississippi rivers. See figure 29 on page 221.

     _Characters for ready recognition._--Differs: From _M. f.
     olivacea_, in males, by width of tympanic bulla which is less than
     rather than more than 8.5 mm., and in adult females by total
     length which is less than rather than more than 345 mm. and by
     mastoid breadth which is less than rather than more than distance
     between articular faces of exoccipital condyle and glenoid fossa;
     from _M. f. occisor_ by a number of average differences including
     smaller size, relatively shorter tail and relatively narrower
     skull (see measurements); from _M. f. spadix_ by least width of
     color of underparts amounting to less than 41 per cent of greatest
     width of color of upper parts, absence of color of underparts on
     ankles and feet, adults with hind foot less than 50 in males and
     40 in females, orbitonasal length less than 15.5 in males and 13.5
     in females, length of tooth-rows less than 18.0 in males and 15.7
     in females, mastoid breadth less than 25.5 in males and 22.0 in
     females; from _M. f. primulina_ in males by interorbital breadth
     averaging more than 24 per cent of basilar length, orbitonasal
     length averaging more than 34 per cent of basilar length or 64 per
     cent of mastoid breadth, tympanic bullae less inflated
     anteromedially, than posteromedially, and in females by
     orbitonasal length amounting to more than two-thirds of mastoid
     breadth, by zygomatic breadth averaging less than 21, and by
     anterolateral margin of tympanic bullae not projecting below
     squamosal; from _M. f. arthuri_ in males, by zygomatic breadth
     more than distance between anterior palatine foramen and anterior
     margin of tympanic bulla and by convex dorsal outline of skull in
     longitudinal axis.

_Description.--Size._--Male and Female:

 =======================================================================
           |   Number   |           |           |Per cent|             |
 LOCALITY  |    of      |   Total   |  Length   |  of    | Length of   |
           |  specimens |  length   |  of tail  |  body- | hind foot   |
           |  averaged  |           |           | length |             |
 ----------+------------+-----------+-----------+--------+-------------+
           |  8 ad. [M] |    415    |    146    |   54%  |    46.0     |
 Massa-    |            | (390-432) | (127-159) |        | (41.0-48.0) |
  chusetts +------------+-----------+-----------+--------+-------------+
           |  4 ad. [F] |    311    |    104    |   50%  |    33.9     |
           |            | (298-321) | (95-114)  |        | (31.5-37.0) |
 ----------+------------+-----------+-----------+--------+-------------+
           | 10 ad. [M] |    411    |    141    |   52%  |    47.1     |
 Liberty   |            | (379-438) | (124-155) |        | (43.0-51.5) |
  Hill,    +------------+-----------+-----------+--------+-------------+
  Conn.    | 6 ad. and  |    318    |    105    |   49%  |    33.0     |
           | sad. [F]   | (303-338) | (80-123)  |        | (31.7-36.0) |
 ----------+------------+-----------+-----------+--------+-------------+
           | 10 ad. [M] |    407    |    130    |   47%  |    46.0     |
 Beaver    |            | (372-431) | (113-143) |        | (42.0-50.0) |
   Dam,    +------------+-----------+-----------+--------+-------------+
  Wisc.    |  4 ad. [F] |    326    |     99    |   43%  |    35.6     |
           |            | (303-338) |  (86-108) |        | (34.6-38.0) |
 ----------+------------+-----------+-----------+--------+-------------+
           | 10 ad. [M] |    371    |    130    |   54%  |    45.0     |
 Washtenaw |            | (350-405) | (115-140) |        | (40.0-50.0) |
   Co.,    +------------+-----------+-----------+--------+-------------+
  Mich.    | 10 ad. [F] |   306     |    97     |   46%  |    34.0     |
           |            | (290-335) | (90-120)  |        | (30.0-40.0) |
 ----------+------------+-----------+-----------+--------+-------------+

     The length of the hind foot averages more than the basal length in
     males whereas the reverse is true in females. The tail, relative
     to the length of the body, is longer in males than in females. The
     average differences in external measurements of the two sexes in
     Massachusetts, are: total length, 104; length of tail, 42; length
     of hind foot, 12.1. In Michigan, where the males are smaller,
     corresponding differences are only, 65, 33, and 11. Weight of 19
     adult males from New York (Hamilton, 1933:294), 225 (196-267)
     grams and in 13 adult females, 102 (72-126) grams. Weights of 2
     adults from Michigan are: [M] 258; [F] 101 grams.

     _Externals._--Longest facial vibrissae black, brown, or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles as shown in
     figure 19.

     _Color._--Upper parts, in summer, Vandyke Brown or darker than
     tone 4 of Burnt Umber of Oberthür and Dauthenay, pl. 304.
     Sometimes approaching tone 2 of Warm Sepia of Oberthür and
     Dauthenay, pl. 305. Underparts, in summer, ranging from white
     through Napthalene Yellow (Peterboro, N. Y.), Pale Orange Yellow
     (eastern Mass.), near Primuline Yellow (unusual specimen from
     Leelanau Co., Mich.) to near (_c_) Deep Chrome (no. 19053, U. S.
     Nat. Mus., Roan Mts., N. C). In winter, all white except tip of
     tail, or upper parts near (12" 1) Rood's Brown and tone 2 of Raw
     Umber of Oberthür and Dauthenay, pl. 301, with underparts white or
     sometimes tinged with yellowish. Tip of tail at all times black.
     Upper parts of uniform color except for occasional slight
     darkening of nose. Color of underparts extends distally on
     posterior sides of forelegs to foot and sometimes over upper sides
     of toes and on medial sides of hind limbs only to knees. Least
     width of color of underparts averaging, in a series of twenty-two
     males, mostly in full winter pelage, from Liberty Hill,
     Connecticut, 21 (11-40) per cent of greatest width of color of
     underparts. In eleven females from the same place, corresponding
     percentages are 20 (14-29). Black tip of tail in same series of
     males, most of which are in full winter pelage, 70 (60-75) mm.
     long; thus longer than hind foot and averaging 50 per cent of
     length of tail-vertebrae.

     _Skull and teeth._--Male (based on ten adults from Massachusetts):
     See measurements and plates 16-18; weight, 3.6 (3.3-4.4) grams;
     basilar length, 44.6 (43.3-46.0); zygomatic breadth less than
     distance between condylar foramen and Ml or than between anterior
     palatine foramen and anterior margin of tympanic bulla; mastoid
     breadth less than postpalatal length; postorbital breadth more or
     less than length of upper premolars and greater than width of
     basioccipital measured from medial margin of one foramen lacerum
     posterior to its opposite; interorbital breadth more or less
     (usually more) than distance between foramen opticum and anterior
     margin of tympanic bulla; breadth of rostrum less than length of
     tympanic bulla; least width of palate less than length of P4;
     anterior margin of tympanic bulla as far posterior to foramen
     ovale as width of 3 to 6 upper incisors; height of tympanic bulla
     more or less than distance from its anterior margin to foramen
     ovale; length of tympanic bulla more than length of lower molar
     and premolar tooth-row and longer or shorter than rostrum;
     anterior margin of masseteric fossa behind or directly below
     posterior fourth of m1.

     Female (based on five adults from Mass.): See measurements and
     plates 31-33; weight, 1.7 (1.2-2.1) grams; basilar length, 36.5
     (35.2-38.1); zygomatic breadth less than distance between condylar
     foramen and M1 or than between anterior palatine foramen and
     anterior margin of tympanic bulla; postorbital breadth more or
     less than length of upper premolars and more than width of
     basioccipital measured from medial margin of one foramen lacerum
     posterior to its opposite; least width of palate more or less
     (usually less) than greatest length of P4; tympanic bulla as far
     posterior to foramen ovale as width of 4 to 5-1/2 upper incisors;
     height of tympanic bulla less than distance from its anterior
     margin to foramen ovale; length of tympanic bulla more than length
     of lower molar and premolar tooth-row and longer than rostrum.

     The skull of the female averages 53 per cent lighter than that of
     the average male.

Comparisons of the skull with those of _M. f. olivacea_, _M. f.
spadix_, _M. f. primulina_, and _M. f. arthuri_, are made in the
accounts of those subspecies. As compared with that of _M. f. occisor_
the skull of adult male _noveboracensis_, is of smaller average size
with relatively (to basilar length of Hensel) lesser mastoid and
zygomatic breadths. In addition to the zygomatic arches of
_noveboracensis_ being less widely bowed outward they seem to be more
rounded posteriorly. Comparisons of subadult females indicate that
these differences exist in the females as well as in the adult males.

_Remarks._--The earliest of the post-Linnaean references to this weasel
mostly were under the specific name _erminea_ in the belief that the
American animal was the same as the larger of the two common species of
weasel in the Old World. The name _noveboracensis_, now in use for this
subspecies, was applied in 1840 and since that time the males usually
have borne that name; the females, because they are smaller, were more
frequently confused with some other species. Audubon and Bachman in
1853 even proposed the name _agilis_ for the female in the mistaken
belief that it was a species distinct from the male. After 1896, when
Bangs correctly classified the weasels of the eastern United States,
the males have been correctly identified and the females, except by a
few authors, likewise have been correctly named. Because many early
American naturalists did their first collecting of mammals in the
geographic range of _noveboracensis_, the person who examines labels of
specimens of this subspecies can find data written in the hand of
Spencer Fullerton Baird, Theodore Roosevelt, and other naturalists
famous for their work as scientists or accomplishments otherwise. The
material is more nearly adequate than is that of many other subspecies
and the number of specimens is exceeded--and only slightly--by that of
the subspecies _nevadensis_, which like _noveboracensis_ has a
relatively large geographic range.

Intergradation with _Mustela frenata spadix_ is indicated by subadult
males from western Wisconsin, namely, one from Gordon, three from
Colfax and one from Meridean. Linear measurements of the teeth of these
specimens are exactly intermediate between those of _spadix_ from Elk
River, Minnesota, to the west, and _noveboracensis_ from, say, Beaver
Dam, Wisconsin, to the east. The specimens from western Wisconsin show
approach to spadix also in that the length of the tooth-rows and
breadth of the rostrum are slightly greater than in _noveboracensis_
from farther east, say, Beaver Dam, Wisconsin.

Indeed, animals from as far east as Beaver Dam itself might be thought
of as showing some approach to _spadix_. Although, along the eastern
seaboard, the upper lips, with rare exceptions, are the same color as
the underparts, farther west, in Michigan and Wisconsin, the lips more
often than not are white. Animals from Beaver Dam have slightly shorter
black tips on the tails, broader extent of the light color of the
underparts and females average slightly larger than typical
_noveboracensis_, say, those from Massachusetts. Each of these
differences reflects characters found better developed in the
_spadix-longicauda_ stock to the west.

Toward the southern part of its range where _noveboracensis_ meets _M.
f. olivacea_ there is a marked increase in yellowness of the
underparts. This coloration of the underparts, since it is not so well
marked in the northern part of the range of _noveboracensis_, might be
regarded as showing intergradation with _olivacea_ and _primulina_,
each of which has far more intensely colored underparts than does
_noveboracensis_. Excepting this increase of yellow on the underparts,
however, there are few if any characters of _noveboracensis_ which
undergo marked change as approach to the range of _olivacea_ is made.
Indeed, the characters of _noveboracensis_ remain constant to within a
relatively short distance of the geographic range of _olivacea_.

Notwithstanding the state of affairs described above, intergradation
seems to take place. Three specimens referred to _noveboracensis_ but
which at the same time are regarded as intergrades with _olivacea_ are
as follows: No. 28.300, Charleston Museum, from five miles east of
York, South Carolina, is an adult female with a badly crushed skull. In
external measurements the specimen agrees with _noveboracensis_. The
underparts, as regards color and width, are intermediate. The general
proportions of the skull and tympanic bullae agree with those of
_noveboracensis_ but the skull is larger than in any female of true
_noveboracensis_ and approaches that of _olivacea_. The same can be
said of a young female, no. 80, Ohio State Museum, from Roswell,
Georgia.

Another female, no. 171559, U. S. Nat. Mus., from Lookout Mountain,
1500 ft., Fort Payne, Alabama, is barely subadult. The external
measurements are nearer those of _olivacea_. The color and narrowness
of the underparts are typical of _noveboracensis_. The proportions and
especially size of the skull show approach to _olivacea_, though they
are nearer to _noveboracensis_ when all features are taken into
account. In the northern part of its range individuals of
_noveboracensis_ attain larger size than farther south. This tendency
reaches its extreme, in males at least, in _M. f. occisor_ of Maine.
Specimens of _noveboracensis_ from the Adirondacks of New York average
larger (see cranial measurements on page 418) than those from farther
south, and thus approach _occisor_ in size as well as in geographic
position. Also, occasional individuals which strongly show characters
of _occisor_ are found even farther south than the Adirondacks of New
York. This is true of no. 96518, U. S. Nat. Mus., [M] ad., from
Lunenburg; Massachusetts. The animal has a large skull of relatively
great width much as in _occisor_, although its external measurements,
relative length of tail and long, terminal, black brush place it with
_noveboracensis_ rather than with _occisor_. Of a pair of specimens
from Ossipee, New Hampshire, the male, no. 77108, U. S. Nat. Mus., has
a long (175 mm.) tail, and short (60 mm.) black pencil as in _occisor_,
although otherwise it is referable to _noveboracensis_. Still another
specimen, a subadult male, no. 4193, Mus. Comp. Zoöl., from Upton,
Maine, has a longer (51 mm.) hind foot than _noveboracensis_ although
it otherwise agrees with that subspecies. As remarked by Bangs
(1899:55), other than fully adult specimens from the range of _occisor_
are "troublesome," and would not be selected as distinct from
_noveboracensis_ if placed in a series of that subspecies, say, from
New York State. In view of the facts that several specimens from
intermediate localities combine the characters of _noveboracensis_ and
_occisor_, that _noveboracensis_ in the northern part of its range
averages larger than it does farther south and thus approaches
_occisor_ in size, and that occasional large specimens resembling
_occisor_ in several, but not all, features sometimes crop up in the
northern part of the range of _noveboracensis_, it appears that
_noveboracensis_ and _occisor_ intergrade. Therefore they are treated
as two subspecies of the single species, _Mustela frenata_.

Intergradation with _M. f. primulina_ has been commented on in the
discussion of that subspecies. Female, no. 159980, U. S. Nat. Mus.,
from Golconda, Illinois, has many characters of _primulina_ but two
young males from there agree better with _noveboracensis_.

Examination of 283 adult and subadult skulls for malformation of the
frontal sinuses revealed only ten that were not obviously malformed.
Two were from New York, one from Massachusetts, one from Pennsylvania,
and six from the 52 specimens from Michigan and Wisconsin. In addition,
skulls of many young and even juveniles were malformed.

     _Specimens examined._--Total number, 555, arranged alphabetically
     by states and provinces and, unless otherwise noted, from north to
     south by counties in each state. Except as otherwise noted
     specimens are in the United States National Museum.

     =Alabama.= _DeKalb County_: Fort Payne, 1.

     =Connecticut.= _Litchfield County_: Riverton, 1[5]; Gaylordsville,
     1. _Hartford County_: East Hartford, 4 (3[5]); Glastonbury, 2[5];
     South Glastonbury, 4[5]. _Windham County_: Plainfield, 2 (1[14]).
     _Fairfield County_: Greenwich, 2[2]. _New London County_: Liberty
     Hill, 35 (33[75], 2[7]).

     =District of Columbia.= Washington, 3; near Washington, 1; Eastern
     Branch, 1; Congress Heights, 1; Benning, 1; no definite locality,
     1.

     =Georgia.= _Towns County_: Young Harris, 1. _Cherokee County_:
     Canton, 1. _Cobb County_: Roswell, 1[81].

     =Indiana.= _St. Joseph County_: Notre Dame, 2[99]. _Porter
     County_: Hebron, 1. _Miami County_: Denver, 5 (4[75], 1[4]).
     _Wells County_: Bluffton, 1. _Howard County_: Russiaville, 1. _Jay
     County_: Salamonia, 1[2]. _Boone County_, 1[2]. _Knox County_:
     Bicknell, 3.

     =Illinois.= _Lake County_: Camp Logan, 3[60]; Fort Sheridan,
     1[60]. _Cook County_: W Northfield, 2; Flossmoor, 1[60]; no
     locality more definite than county, 1. _Du Page County_:
     Bloomingdale Spg., 1[60]. _Carroll County_: Savanna, 1[87].
     _McLean County_: Normal, 1[7]. _Champaign County_: Harwood
     Township, 1[7]. _Pike County_?: Milton Spring, 1[60]. _Pope
     County_: Golconda, 3.

     =Kentucky.= _Woodford County_: Midway, 1. _Hancock County_:
     Hawesville, 1.

     =Maine.= _Oxford County_: Upton, 1[75]; Bethel, 1[74].

     =Maryland.= _Howard County_: Long Corner, 1; Hanover, 1.
     _Montgomery County_: Gaithersburg, 1; Garret Park, 1; Chevy Chase,
     1; Bethesda, 1. _Prince Georges County_: Laurel, 18; Plummer
     Island, 3; Oxon Hill, 1. _Talbot County_: Easton, 1. _Dorchester
     County_: Cambridge, 5[40].

     =Massachusetts.= _Middlesex County_: Wilmington, 6; Burlington, 6;
     Lexington, 1[75]; Wayland, 2[75]. _Berkshire County_: New
     Marlboro, 1[5]. _Worcester County_: Lunenburg, 2; Lancaster,
     1[75]; Princeton, 2[75]. _Norfolk County_: So. Weymouth, 1[75].
     _Plymouth County_: Wareham, 5[75].

     =Michigan.= _Marquette County_: Michigamme, 1. _Charlevoix
     County_: Thumb Lake, 1[76]; 1/2 mi. N Thumb Lake, 1[76]. _Leelanau
     County_: Leland, 3[76]; Duck Lake, 2 mi. S Leland, 1[76]; Lost
     Pond, 8-1/2 mi. S Leland, 1[76]. _Osceola County_: Le Roy, 2[76].
     _Huron County_: Rush Lake, 1[76]. _Saginaw County_: East Saginaw,
     1. _Oakland County_: Royal Oak, 4[76]; South Lyon, 1[76].
     _Livingston County_: Portage Lake, 1[76]. _Washtenaw County_:
     Portage Lake, 6[76]; Waterloo, 2[14]; Lima, 1[76]; Ann Arbor,
     11[76]; 3 mi. E Ann Arbor, 1[76]; 2 mi. SE Ann Arbor, 1[76]; 2 mi.
     S Ann Arbor, 1[76]; 3 mi. S Ann Arbor, 1[76]; Dixboro, 1[76];
     Pittsfield, 3 (2[76]); Saline, 1[76]; near Saline, 2[76]; 1 mi. S
     Saline, 2[76]; York, 2[76]; Manchester, 2[76]. _Lenawee County_:
     Morenci, 1[76]. _Cass County_: Marcellus Township, 1[76]. _Berrien
     County_: Harbert, 1[76]; Warren Wood Preserve, 1[76]; Warren
     Woods, 1[76].

     =New Hampshire.= _Grafton County_: Franconia, 1[2]. _Carroll
     County_: South Chatham, 4 (3[5]); Ossipee, 2; Intervale, 1[5].
     _Merrimack County_: Webster, 2[75].

     =New Jersey.= _Morris County_: Morristown, 1. _Essex County_: West
     Orange, 1[2]. _Mercer County_: Princeton, 1[1]. _Ocean County_:
     Point Pleasant, 1[2]. _Camden County_: Haddonfield, 1[1].
     _Cumberland County_: Millville, 2[74].

     =New York.= _St. Lawrence County_: Ogdensburg, 1[74]. _Clinton
     County_: Rouses Point, 1[80]. _County_?: Adirondacks, 12. _Essex
     County_: Elizabethtown, 1; Schroon Lake, 1; no locality more
     definite than county, 1. _Lewis? County_: Locust Grove, 4; Lyons
     Falls, 1. _Warren County_: Lake George, 6; Caldwell, 1. _Hamilton
     County_: Beaver Brook, 1/2 mi. above mouth Indian Lake, 1[80].
     _Oswego County_: Scriba, 2[74]; Palermo, 1[74]. _Monroe County_:
     Penfield, 3. _Madison County_: Peterboro, 6 (2[75]). _Schoharie
     County_: Schoharie, 1[2]. _Rensselaer County_: East Shodack,
     1[80]. _Tompkins County_: Taughannock Falls, 2[58]; Ithaca, 4
     (3[58]); Glenside, Ithaca, 1[58]; 6 mi. Creek, Ithaca, 1[58].
     _Green County_: Lanesville, 1[2]. _Orange County_: Poplopen's
     Pond, 1[2]; Highland Falls, 1[2]. _Putnam County_, 1[19].
     _Westchester County_: Sing Sing, 4; Armonk, 1[2]; Hastings, 3
     (2[2], 1[19]). _Nassau County_: Flushing Meadows, 1[2]; Flushing,
     1[58]; near Flushing, 1[2]; Oyster Bay, 2. _Long Island_: Cold
     Spring Harbor, 1; Bridgehampton, 1[2]. _County_ in question:
     Severance, 3; Lake Grove (Long Island?), 1.

     =North Carolina= (east to west by counties). _Wake County_:
     Raleigh, 4 (1[2], 1[75], 2[76]). _Mitchell County_: Magnetic City,
     foot of Roan Mountain, 6; Roan Mt., 1; Roan Mt., 6000 ft., 3.
     _Buncombe County_?: Valley of Black Mts., 1[2]. _Madison County_,
     2[11].

     =Ohio.= _Trumbull County_: Warren, 1[93]. _Seneca County_: Tiffin,
     1[81]. _Summit County_: Ira, 2[81]. _Crawford County_: Galion,
     1[81]. _Ashland County_: Loudonville, 1[76]. _Auglaize County_:
     New Bremen, 3[81]. _Franklin County_: 3 mi. N Columbus, 1[81];
     Minerva Park, Columbus, 5[81]. _Fairfield County_: Sec. 32,
     Pleasant Twp., 1[81]; Lancaster, 1[81]. _Clinton County_:
     Reesville, 1; 1/2 mi. S and 1/2 mi. W Wilmington, 2[74]. _Pike
     County_: Waverly, 1[81].

     =Ontario.= _Sudbury District_: Metagama, 2[86]. _Carleton County_:
     Ottawa, 2[77]. _Muskoka County_: Lake of Bays, 1; Bracebridge, 1.
     _Haliburton County_: Gooderham, 1[60]. _Simcoe County_: Orillia, 4
     (2[2], 2[60].) _Prince Edward County_: Bloomfield, 1[77]. _York
     County_: Toronto, 1[2]. _Waterloo County_: Branchton, 3[60];
     Preston, 2[77]; no locality save county, 1[60]. _Welland County_:
     Ridgway, 1[14]. _Elgin County_: St. Thomas, 1[77]. _Essex County_:
     Kingsville, 1[77]; Point Pelee, 1[77].

     =Pennsylvania= (east to west by counties). _Crawford County_:
     Pymatuning Swamp, 3-1/2 mi. W Linesville, 1[9]; Meadville, 2[9].
     _Beaver County_: Beaver, 1[9]; Raccoon Creek, 1[9]. _Butler
     County_: Mars, 1[9]; Leasuresville, 4[9]. _Allegheny County_:
     Allegheny, 1. _Warren County_: Bear Lake, 2[9]. _Westmoreland
     County_: Kingston, 1[9]; Laughlinstown, 2[9]. _Somerset County_:
     Confluence, 1[9]; Tub Mill Run, 2 mi. N Springs, 1[9]. _Jefferson
     County_: Siegel, 1[9]. _Clearfield? County_: Penfield, 1[9].
     _Cambria County_: Cresson, 1[9]. _Fulton County_: Well's Tannery,
     1[9]. _Clinton County_: near Round Island, 2[1]. _Cumberland
     County_: Carlisle, 1. _Snyder County_: 5 mi. S Selinsgrove, 1.
     _Northumberland County_: Pottsgrove, 1. _Union County_:
     Mifflinburg, 1. _Sullivan County_: Lopez, 7 (4[1], 3[74]).
     _Chester County_: Westtown, 1[1]; Valley Forge, 1[1]; W Bradford
     Township, 1[1]; no locality more definite than county, 3.
     _Philadelphia County_: Holmsburg, 2[1]. _Bucks County_: 1[1].
     _Pike County_: Milford, 1.

     =Rhode Island.= _Providence County_: Chepachet, 1. _Washington
     County_: Lake Warden, 2.

     =Quebec.= _Megantic County_: Black Lake 1[77]. _County_ in
     question: Meach Lake, 1[77].

     =South Carolina.= _York County_: 5 mi. E York, 1[11]. _Laurens
     County_: Laurens, 1[39].

     =Tennessee.= _Campbell County_: Highcliff, 1. _Carter? County_:
     Roan Mts., 1[2]. _Hamilton County_: Walden Ridge, near Soddy, 3.

     =Vermont.= _Windsor County_: Hartland, 1[2].

     =Virginia.= _Shenandoah County_: Toms Brook, 1. _Arlington
     County_: Arlington, 1; Ballston, 1; Alexandria, 1. _Fairfax
     County_: Falls Church, 3; Mt. Vernon, 2; no locality more
     definite than county, 1. _Prince William County_: Occoquan, 1.
     _Essex County_: Montague, 1. _Prince George County_, 1. _Norfolk
     County_: Wallaceton, 1. _Grayson County_: Mt Rogers, 3. _County_
     in question: Dismal Swamp, 1; Massanutten Mt., 1.

     =West Virginia.= _Hardy County_, 1. _Pendleton County_: radius of
     2 mi. Smoke Hole, 1[74]. _Greenbriar County_: White Sulphur,
     2[60].

     =Wisconsin.= _Douglas County_: Gordon, 1[104]. _Vilas County_:
     Mamie Lake, 4. _Dunn County_: Colfax, 4[104]; Meridean, 1[104].
     _Door County_: state game farm, 17[104]; no locality more definite
     than county, 1[104]. _Dodge County_: Rolling Prairie, 1[50];
     Beaver Dam, 52[50]. _Dane County_: Wingra Lake, 1[104]. _Waukesha
     County_: Pewaukee, 2[104]. _Racine County_: Waterford Township,
     2[104]. _Rock County_: Milton, 1[104]; Bowers Lake, 1[104].
     _Walworth County_: Lane's Mill, 8 mi. N Elkhorn, 7 (1[104],
     6[54]); Delavan, 7.


=Mustela frenata occisor= (Bangs)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

    _Putorius occisor_ Bangs, Proc. New England Zool. Club, 1:54, June
      9, 1899.

    _Mustela occisor_, Miller, U. S. Nat. Mus. Bull., 79:98, December
      31, 1912.

    _Mustela frenata occisor_, Hall, Carnegie Instit. Washington Publ.
      473:104, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 9102, coll. of E. A. and
     O. Bangs in Mus. Comp. Zoöl.; Bucksport, Hancock County, Maine;
     January 15, 1899; obtained by Alvah G. Door but measured and sexed
     by O. Bangs.

     The skin is well made and in good condition. It is in full, white
     winter-dress with black-tipped tail. The skull has the posterior
     half of the left zygomatic arch broken away; otherwise the skull
     is unbroken and complete. Left I3 and right P3 are missing. The
     teeth otherwise all are present and entire.

     _Range._--Maine; possibly north locally to south side of St.
     Lawrence River in Quebec and possibly occurring in western New
     Brunswick. Zonal range Canadian and probably Transition. See
     figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     noveboracensis_ by a number of average differences including
     larger size, relatively longer tail and relatively wider skull
     (see p. 225, and measurements on pp. 418, 419).

     _Description._--_Size._--Male: Five adults yield average and
     extreme measurements as follows: Total length, 443 (430-465);
     length of tail, 163 (154-175); length of hind foot, 50 (47-54).
     Tail averages 58 per cent as long as head and body. Length of hind
     foot averages more than basal length.

     Female: Measurements of two subadult female topotypes are as
     follows: Total length, 346, 318; length of tail, 116, 110; length
     of hind foot, 39, 35.5.

     Tail amounts to 50 per cent and 54 per cent of body-length
     respectively. Length of hind foot more or less than (about equal
     to) basal length.

     The average differences in external measurements of the two sexes
     are: Total length, 111; length of tail, 50; length of hind foot,
     12.5.

     _Externals._--As described in _Mustela frenata noveboracensis_.

     _Color._--As described in _Mustela frenata noveboracensis_ except
     that black tail-tip in series of 10 males in full winter pelage 60
     (45-80) mm. long; thus averaging 39 per cent of length of tail
     vertebrae.

     _Skull and teeth._--Male (based on 3 adults): See measurements and
     plates 16-18. As described in _Mustela frenata noveboracensis_
     except that: Weight, 4.2 (4.1-4.3) grams; basilar length, 45.7
     (44.9-46.9); zygomatic breadth more or less than (about equal to)
     distance between anterior palatine foramen and anterior margin of
     tympanic bulla; least width of palate rarely less than length of
     P4; anterior margin of masseteric fossa behind or directly below
     posterior half of m2.

     Female (based on 2 subadults): See measurements and plates 31-33.
     As described in _Mustela frenata noveboracensis_ except that:
     Weight, 2.0 (1.9-2.1) grams; basilar length, 37.3, 38.2.

     Comparison of the skull with that of _M. f. noveboracensis_ is
     made in the account of that subspecies.

_Remarks._--Excepting a specimen in the Academy of Natural Sciences of
Philadelphia, obtained in 1893, and two in the Boston Society of
Natural History, obtained in 1925, I have seen no material of this
subspecies in addition to that examined by Bangs at the time he
prepared the original description in 1899.

Anderson (1945:56, 57) records a specimen, Canadian National Museum
Catalogue Number 18426, from Kamouraska County, Quebec, as of this
subspecies and thinks that _occisor_ occurs north of Maine "locally to
south side of lower St. Lawrence River in Quebec; probably also in
western New Brunswick."

So far as the available material of occisor permits one to judge, it is
distinguished from _noveboracensis_ by a combination of characters no
one of which invariably can be relied upon as diagnostic. Employing
adult males, average differences indicate that _M. f. occisor_ is
larger in each of the external and cranial measurements; tail
relatively longer; black tip of tail relatively shorter; mastoid and
zygomatic breadth relatively greater and zygomatic arches more nearly
square posteriorly.

Considering the large number of specimens of _noveboracensis_ which are
available in comparison with the few of _occisor_ it is not surprising
that some _noveboracensis_ should be found which exceed in size those
of _occisor_. This is the case as regards the basilar length of a very
old male, no. 96518, U. S. Nat. Mus., from Lunenburg, Massachusetts.
Also, the skull is actually broader than any of those of _occisor_.
However, this specimen is much older than any _occisor_ examined. In a
female, no. 4260, Mus. Comp. Zoöl., from Liberty Hill, Connecticut, the
skull is longer (but narrower) than in either of the two available
females of _occisor_.

The average differences pointed out above which characterize this
extreme northern population of _noveboracensis_-like weasel in
comparison with true _noveboracensis_ without much question are
geographic variations. Whether or not these variations are of a degree
sufficient to warrant nomenclatural recognition is debatable. With
equally scanty material from other regions I have not named variations
seemingly as great as those shown by _occisor_. The paucity of material
of _occisor_ is a handicap in making a decision in this instance.

Each of the adult and subadult specimens, except the one from Perry,
shows malformation resulting from the infestation of the frontal
sinuses with parasites.

     _Specimens examined._--Total number, 18, listed by counties from
     west to east and unless otherwise indicated in the Museum of
     Comparative Zoölogy.

     =Maine.= _Oxford County_: South Andover, 2 (Boston Soc. Nat.
     Hist.); Umbagog Lake, 1. _Franklin County_: Seven Pd. Township, 1.
     _Piscataquis County_: Grenville, [= Greenville?], 1. _Hancock
     County_: Bucksport, 10. _Washington County_: 3rd Mopang Lake, 1
     (Acad. Nat. Sci. Phila.); Perry, 1 (Boston Soc. Nat. Hist.).
     _County_ in question: Moosehead Lake, 1.


=Mustela frenata primulina= Jackson

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

    _Mustela primulina_ Jackson, Proc. Biol. Soc. Washington, 26:123,
      May 21, 1913.

    _Putorius noveboracensis_, Baird, Mamm. N. Amer., p. 166, 1858
      (part).

    _Mustela longicauda longicauda_, Dice, Journ. Mamm., 4:108, May 9,
      1923.

    _Mustela longicauda primulina_, Linsdale, Journ. Mamm., 9:141, May
      9, 1928.

    _Mustela frenata primulina_, Hall, Carnegie Instit. Washington
      Publ. 473:104, November 20, 1936.

    _Mustela frenata_, Leopold and Hall, Journ. Mamm., 26:143, July 19,
      1945.

     _Type._--Male?, young, skull and skin; no. 168006, U. S. Nat.
     Mus., Biol. Surv. Coll.; 5 miles northeast of Avilla, Jasper
     County, Missouri; May 11, 1905; obtained by Hartley H. T. Jackson;
     original no. 7869X.

     The skin lacks the distal part of the tail--the part which bears
     the black tip. Otherwise the skin is complete and well preserved.
     The teeth of the permanent dentition all are present and entire.
     The lower jaws are complete and unbroken. The skull is broken
     transversely through the interorbital region, transversely through
     the braincase and longitudinally through the basioccipital. Both
     zygomatic arches are gone. The type is judged to be a male rather
     than a female as stated by the original describer, Jackson
     (1913:123), whose measurements of hind foot, interorbital
     constriction, maxillary tooth-row, and mandibular tooth-row agree
     with those of males and are larger than those of any female seen
     of this subspecies.

     _Range._--Upper and Lower Austral life-zones west of the
     Mississippi River in Missouri and Arkansas, the southeastern half
     of Iowa, eastern half of Kansas and Oklahoma, northern Louisiana
     and northeastern Texas. Southern and southwestern limits of range
     undetermined. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     noveboracensis_ in males by interorbital breadth averaging less
     than 24 per cent of basilar length, orbitonasal length averaging
     less than 34 per cent of basilar length or 64 per cent of mastoid
     breadth, tympanic bullae as much inflated anteromedially as
     posteromedially, and in females by orbitonasal length amounting to
     less than two-thirds of mastoid breadth, by zygomatic breadth
     averaging more than 21 mm., and by anterolateral margin of
     tympanic bulla projecting below squamosal; from _M. f. spadix_ by
     least width of color of under parts amounting to less than 40 per
     cent of greatest width of color of upper parts, by absence of
     color of underparts on hind leg below knee, and by smaller size
     (hind foot less than 50 in males and 40 in females; orbitonasal
     length less than 15.5 in males and 13.5 in females; length of
     tooth-rows less than 18 in males and 15.7 in females; mastoid
     breadth less than 25.5 in males and 22 in females); from _M. f.
     longicauda_ by Brussels Brown rather than near (_h_) Clay Color of
     upper parts, least width of underparts less than 40 per cent of
     greatest width of color of upper parts, absence of color of
     underparts on hind leg below knee, zygomatic breadth less than
     28.8 in males and 24.1 in females; from _M. f. neomexicana_ by
     Brussels Brown rather than Buckthorn Brown color of upper parts,
     in absence of white frontal spot and broad white bands on sides of
     head, in anterolaterally rounded, rather than "square," tympanic
     bullae and in zygomatic breadth of less than 30 in males and 24 in
     females; from _M. f. frenata_ and _M. f. texensis_ by absence of
     white facial markings and smaller size (basilar length of adult
     males less than 47, tail-length less than 155 in males, and hind
     foot less than 40 in females); from _M. f. arthuri_ by less evenly
     spreading zygomatic arches (see pls. 16, 17 and 18), greater
     inflation of the tympanic bullae anteromedially and more nearly
     straight (less convex) dorsal outline of skull.

     _Description._--_Size._--Male: Eighteen adults and subadults from
     Douglas County, Kansas, yield average and extreme measurements as
     follows: Total length, 397 (371-440); length of tail, 133
     (120-147); length of hind foot, 43 (40-47). Tail averages 50 per
     cent as long as head and body. Length of hind foot averages less
     than basal length. Corresponding measurements, originally taken in
     inches and fractions thereof, of 9 adults and subadults from Boone
     County, Arkansas, are as follows: 413 (384-438); 138 (127-155); 41
     (38-44).

     Female: Six adults and subadults from Douglas County, Kansas,
     yield average and extreme measurements as follows: Total length,
     339 (317-355); length of tail, 107 (95-115); length of hind foot,
     35 (34-37). Tail averages 46 per cent of length of head and body.
     Length of hind foot less than basal length. Corresponding
     measurements, originally taken in inches and fractions thereof, of
     5 adults and subadults from Boone County, Arkansas, are as
     follows: 355 (332-397); 113 (101-127); 33 (29-38).

     The average differences in external measurements of the two sexes,
     in Douglas County, Kansas, are: Total length, 58; length of tail,
     26; length of hind foot, 8. An adult male from Boone Co., Iowa,
     weighed 293 grams.

     _Externals._--Longest facial vibrissae black or dark brown (often
     both colors in same specimen) and extending beyond ear; carpal
     vibrissae colored either like underparts or upper parts and
     extending to apical pad of fifth digit; hairiness of foot-soles as
     shown in figure 20.

     _Color._--Upper parts, in summer, Brussels Brown to near (14 _n_)
     Brussels Brown, or tones 2 to 4 of Raw Umber of Oberthür and
     Dauthenay, pl. 301. Chin and rarely upper lips white. Remainder of
     underparts Picric Yellow to Primuline Yellow. In winter, color
     essentially the same except for smoke-gray effect in upper parts
     and more whitish in underparts. Tip of tail at all times black.
     Upper parts of uniform color except for occasional darkening of
     nose and mid-dorsal region. Color of underparts extends distally
     on posterior sides of forelegs onto antipalmar faces of toes, on
     medial sides of hind legs only to a point between knee and ankle.
     Least width of color of underparts averaging, in a series of 21
     males from Lawrence, Kansas, 23 (9-35) per cent of greatest width
     of color of upper parts. Black tip of tail in same series, most of
     which are in full winter pelage, 52 (40-70) mm. long; thus longer
     than hind foot and averaging 39 per cent of length of
     tail-vertebrae.

     _Skull and teeth._--Male (based on ten adults from Douglas County,
     Kansas): See measurements and plates 16-18; weight, 3.7 (3.3-4.2)
     grams; basilar length, 44.8 (43.8-46.0); zygomatic breadth more or
     less (less in 80 per cent) than distance between condylar foramen
     and M1 or than between anterior palatine foramen and anterior end
     of tympanic bulla (less in 70 per cent); mastoid breadth more or
     less (less in 80 per cent) than postpalatal length; postorbital
     breadth less than length of upper premolars and, except in one
     specimen, more than width of basioccipital measured from medial
     margin of one foramen lacerum posterior to its opposite;
     interorbital breadth more or less (less in 70 per cent) than
     distance between foramen opticum and anterior margin of tympanic
     bulla; breadth of rostrum less than length of tympanic bulla;
     least width of palate less than outside length of P4 (except in
     one specimen); anterior margin of tympanic bulla as far posterior
     to foramen ovale as width of 2-1/2 to 5 upper incisors; height of
     tympanic bulla more (except in one specimen) than distance from
     its anterior margin to foramen ovale; length of tympanic bulla
     more than length of lower molar and premolar tooth-row and longer
     (except in one specimen) than rostrum; anterior margin of
     masseteric fossa behind or just below posterior eighth of m1.

     Female (based on 5 adults and subadults from Douglas County,
     Kansas): See measurements and plates 31-33; weight, 2.2 (2.0-2.4)
     grams; basilar length, 38.9 (37.6-40.7); zygomatic breadth less
     than distance between condylar foramen and M1 or than between
     anterior palatine foramen and anterior margin of tympanic bulla;
     postorbital breadth less than length of upper premolars and except
     in one specimen, more than width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite;
     least width of palate less than greatest length of P4; tympanic
     bulla as far posterior to foramen ovale as width of 3 to 5 upper
     incisors; height of tympanic bulla more or less than distance from
     its anterior margin to foramen ovale; length of tympanic bulla
     more than length of lower molar and premolar tooth-row and longer
     than rostrum.

     The skull of the female averages 41 per cent lighter than that of
     the male.

Compared with the skull of _M. f. noveboracensis_ from Massachusetts,
that of the male of _primulina_, in dorsal view, is seen to be shorter
anteriorly to the postorbital processes and to have a more marked
postorbital constriction. In lateral view the dorsal outline of the
skull of _primulina_ is less concave in the postorbital region. In
ventral view the skull of _primulina_ is seen to be wider across the
mastoid processes and zygomatic arches but the most pronounced
difference is in the tympanic bullae. In _noveboracensis_ each bulla is
scooped out on the anterior part of the medial face and appears to be
narrower anteriorly than posteriorly whereas in _primulina_ the
anterior part of the medial face is not scooped out but is moderately
inflated and the bulla appears to be of uniform breadth anteriorly and
posteriorly. By actual measurement the breadth of the bulla averages 59
per cent of its length in _primulina_ but only 50 per cent in
_noveboracensis_. Other respects in which the skull of the male of
_primulina_ differs from that of _noveboracensis_ are as follows:
Linear measurements of teeth more; relative to the basilar length, the
length of the tooth-rows averages more, whereas the interorbital
breadth and orbitonasal length are less.

When skulls of females are compared, each of the differences mentioned
above is found to apply, except that the degree of difference is in
some parts greater, for example, in the tympanic bullae. In
_primulina_, the bulla is in general like that of the male
_noveboracensis_, whereas in the female _noveboracensis_ it is less
inflated, especially anteromedially, shorter, relatively narrower, and
in ventral view projects little or none below the squamosal floor of
the braincase. The breadth of the bulla averages 51 per cent of its
length in _primulina_ but only 47 per cent in _noveboracensis_. The
bullae project below the basioccipital on the average, for a distance
of 2.9 millimeters in female _primulina_ and only 2.3 millimeters in
female _noveboracensis_. In _primulina_ the temporal ridges are well
developed and fuse to form a low sagittal crest, but in
_noveboracensis_ the ridges are absent. Also, in _primulina_ the
mastoid processes project farther laterally beyond the braincase. The
skull of female _noveboracensis_ is much lighter than that of
_primulina_. Average weights of the two are 1.7 and 2.2 grams. The
skulls of females of _primulina_ and _noveboracensis_ differ more than
do the skulls of males.

Compared with the skull of _spadix_, that of the male, and the female,
of _primulina_ averages smaller in every part measured. Expressed in
percentages of the basilar length, the two depth measurements of the
skulls are not significantly different, but, excluding the measurements
of the bullae and teeth, the other cranial measurements are less. The
main difference in relative proportions is in the tympanic bullae which
average only a half millimeter shorter in males of _primulina_ and one
and one-tenth millimeters shorter in females. The bullae are,
therefore, relative to the basilar length, longer in _primulina_. The
skull of _primulina_, then, differs from that of _spadix_ mainly in
smaller size and relatively longer tympanic bullae, especially in
males.

Compared with the skull of _M. f. longicauda_, that of both sexes of
_primulina_ averages smaller in every part measured, except in males
where the length of the tympanic bulla, and breadth and length of M1
are the same or slightly larger in _primulina_. Relative to the basilar
length, the length of the tympanic bullae, and in females only, the
depth measurements are greater in _primulina_ but all the others, in
both sexes, are less. These ratios reflect the relative narrowness of
the skull of _primulina_. Upon direct comparison the narrowness is
especially noticeable in the interorbital region, mastoid region,
tympanic bullae, and across the zygomata.

Compared with the skull of _M. f. neomexicana_ that of both sexes of
_primulina_ averages smaller in every part measured. Excepting the
measurements of the teeth, most of the other measurements are
constantly larger. Relative to the basilar length, the length of
tooth-rows and length of tympanic bulla are more, but excepting the
depth measurements, the others are less. Still other differences are,
in _primulina_, less well-developed sagittal crest, anterolateral
corner of bulla rounded rather than "square," and in males a
transversely convex rather than flat interorbital region.

Compared with _M. f. frenata_ and _M. f. texensis_, the skulls of males
of _primulina_ differ in being smaller in every part measured but
relative to the basilar length, have longer tooth-rows, a lesser
zygomatic breadth and are less constricted interorbitally.

Compared with the skull of _M. f. olivacea_, those of both sexes of
_primulina_ average smaller in every part measured, have shallower
(dorsoventrally) tympanic bullae, a lower sagittal crest and slightly
weaker postorbital processes on the frontals. Relative to the basilar
length, the several cranial measurements are about the same.

Comparison of the skull with that of _M. f. arthuri_ has been made in
the account of that subspecies.

_Remarks._--The first specimens of this race known to have been
preserved in study collections are one in the United States National
Museum, taken at Bridge, Carroll County, Missouri, many years ago by J.
Burbage, and less than a dozen specimens preserved before 1900 from
eastern Kansas in the University of Kansas Museum of Natural History.
In 1913 Hartley H. T. Jackson bestowed a name on this animal on the
basis of two specimens taken by him in southwestern Missouri. Later,
through the efforts of Charles D. Bunker, and his associates at the
University of Kansas, nearly 100 specimens were saved from eastern
Kansas, principally from Douglas County. In the course of the present
study, Lawrence V. Compton obtained a topotype for the California
Museum of Vertebrate Zoölogy, and with the assistance of Mr. B. G.
Roberts, a good series of specimens from Boone County, Arkansas, was
preserved in the same museum. In the early years of the 20th Century,
the late B. H. Bailey at Coe College, Iowa, collected specimens from
that state. The specimens from these several sources suffice to give a
relatively clear idea of the characters of this subspecies.

_Mustela frenata primulina_ is closely related to _M. f.
noveboracensis_, from which, on the average, it differs in the lighter
color of the upper parts of the summer coat, in the more intense
coloring of the underparts, and in certain cranial features pointed out
above. In the southern part of its range, however, _noveboracensis_ has
the underparts only a little less intensely colored with yellow than
_primulina_. Also, the skull of the one topotype from 7-1/2 miles
southeast of Carthage, a subadult male in brown, winter pelage, is
almost exactly intermediate between that of _noveboracensis_ from
Massachusetts and _primulina_ of Douglas County, Kansas, and Boone
County, Arkansas. _M. f. primulina_ often has the underparts white in
winter, as does this topotype which agrees with the average of
_noveboracensis_ in small size of teeth and narrowness across the
mastoid processes and zygomatic arches. However, it agrees with
_primulina_ in shape and relative size of the rostrum. It is almost
exactly intermediate in shape and width of the tympanic bullae.

Three other males, but no females, all in winter pelage, are available
from eastern Missouri. Of the two from Silex, Lincoln County, one is
nearer _noveboracensis_ and the other nearer _primulina_ on the basis
of cranial characters. The third specimen, from four miles south of
Lesterville, so far as I can determine by examination of individual
cranial characters and tabulation of results, is exactly intermediate.
Final decision on the proper allocation of specimens from the parts of
Missouri represented can best be made when skulls of females are
available. From the fact that the skull of the female referred to
_noveboracensis_ from Golconda, Illinois, shows almost as many
characters of _primulina_ as of _noveboracensis_, it is judged that
females from as far west as Silex and Lesterville, Missouri, will show
even more characters of _primulina_ and so be referable to that form.
If this supposition be correct, the present reference of the almost
exactly intermediate males, from eastern Missouri, will stand;
otherwise, it may not.

Additional intergrades with _noveboracensis_ are available from eastern
Iowa. Of five specimens from Hillsboro, Iowa, two males and a female
have tympanic bullae like those of _primulina_ but the other two males
have bullae like those of _noveboracensis_. The female is smaller than
_primulina_ and in this small size and in general configuration of the
skull, viewed dorsally, is more nearly like _noveboracensis_. As a
whole, the population averages almost exactly intermediate. The same is
true of 3 males and one female from Muscatine. The subadult male from
Keosaqua, to my eye, resembles _noveboracensis_ in the greater length
of the skull anteriorly to the postorbital processes, and in the
relative narrowness across the mastoidal region, but otherwise is more
like that of _primulina_. Two males and one female from Tipton,
although in each instance variously intermediate, are as a whole nearer
_primulina_, No. 2865, Coe College, male adult, from Cedar Rapids, has
characters of the three races, _spadix_, _noveboracensis_ and
_primulina_. In the skull, the width suggests _spadix_, the narrow
mastoid region, _noveboracensis_, and the tympanic bullae are as in
_spadix_ or _primulina_. One male, no. 12, Coe College, from Dubuque,
is as narrow across the mastoid region as is _noveboracensis_ although
the bullae are well inflated as in _primulina_. The skull, without
corresponding skin, of a female, no. 140a, Iowa State College, from
Green's Island, also resembles _noveboracensis_ in narrowness of the
mastoidal region, and in small size of skull, but in larger teeth,
broader tympanic bullae, and sagittal crest is referable to
_primulina_. Of two females from Vinton, one adult is typical of
_primulina_ but the other, a subadult, is practically indistinguishable
from female _noveboracensis_, from Ann Arbor, Michigan. Three males
from Vinton agree well with _primulina_ except that the interorbital
region is wider than average and thereby suggests _spadix_ or
_noveboracensis_. An adult female from New Hartford also is typical of
_primulina_ except for the broader interorbital region. Three males
from Fayette are typical of _primulina_.

Other specimens from Iowa are intergrades with _spadix_, or if not with
_spadix_, with the animal of northwestern Iowa which in some ways
combines the characters of _longicauda_ and _spadix_. For example, no.
2665, Coe College, an adult male from Davenport, has the anterior part
of the skull (all that is preserved) heavily ridged as in _spadix_ and
in addition, the underparts are marked with the shade of reddish
displayed by topotypes of _spadix_ and with some yellowish as seen in
_longicauda_. The color pattern, however, is as in _primulina_. A young
male, no. C-51, Iowa State College, from Kelley, Story County, has
anteriorly truncate bullae as are more frequently found in the
_longicauda-spadix_ stock of northwestern Iowa, than in _primulina_. In
other respects, the animal, in so far as can be judged from the broken
skull, agrees with _primulina_ as it certainly does in color, color
pattern, and external measurements. An adult male, no. 499a, Iowa State
College, from 2 miles east of Ledges St. Park, in Boone County, in
short body, size of teeth, and size of skull, in so far as the broken
parts can be measured, resembles _primulina_ more closely than it does
any other subspecies. The long tail, long hind foot, wide extent of the
light-colored underparts, and extension of the color of the underparts
onto the hind feet are more as in _spadix_. Other intergrades with
_spadix_ from Iowa are mentioned in the account of _spadix_.

The specimen from Swartz, Louisiana, suggests intergradation with
_arthuri_ in that the anteromedial part of the tympanic bulla is less
inflated than in typical _primulina_.

Intergrades with _longicauda_ are available from Riley and Pratt
counties, Kansas. No. 7182, Univ. Kans., subadult male in winter
pelage, from near Winkler, has a skull of larger size as in
_longicauda_ with which race it seems to agree in large size of body,
tail and hind foot, although the collector's measurements are lacking.
Color pattern and relative proportions of the skull throughout are as
in _primulina_. The young male, no. 3495, Univ. Kans., from Pratt,
Kansas, agrees in external measurements and large size of skull with
_longicauda_, but has the color and color pattern precisely as in
_primulina_. The teeth are smaller as in _primulina_. Immaturity
prevents judging of its relationships on the basis of relative
proportions of the skull.

The two specimens, skins only, available from Oklahoma, are
provisionally referred to _primulina_. These are remarkable for the
restriction of the color of the underparts and for the intensity of the
yellow coloration of the underparts. The specimen from Norman has the
color of the underparts entirely absent from the hind legs and not
extending posteriorly to the penis. On the chest and lower throat,
large spots of color of the upper parts are present and the yellow area
of the underparts on the belly is narrower than in any other specimen
of _primulina_ examined. The specimen from 8 miles northwest of
Stillwater has the color of the underparts only a little less
restricted although this color does extend over the inguinal region
almost to the knees. The skin of the posterior part of the body of a
weasel is available from 10 miles south of Sulphur Springs, Texas. It,
likewise, is only provisionally referred to _primulina_. The coloration
is about as in the specimens from Oklahoma but the distribution of the
color of the underparts cannot be made out.

The dark color of the upper parts occurs far westward in animals which
otherwise display characters of _longicauda_. Among these intergrades,
the larger size of _longicauda_ generally is combined with this dark
color. This geographic behavior of the dark color of the upper parts is
analogous to the condition described in _M. f. spadix_. Stated in
another way, the dark color of the upper parts is the character, of the
eastern animal, last to disappear as one goes westward across the
Mississippi Valley toward the range of _longicauda_ which is a
subspecies of markedly different size, shape of skull, and coloration.

Only two of 29 specimens from Kansas show infestation of the frontal
sinuses. All four of the specimens from Missouri have the frontal
sinuses malformed as do 9 of the 14 from Arkansas examined in this
respect.

An adult female from Boone County, Iowa, bears the date May 9, 1938,
and the annotation by T. G. Scott, "Fox-killed."

     _Specimens examined._--Total number, 131, arranged alphabetically
     by states and from north to south by counties in each state.
     Except as otherwise indicated, specimens are in the University of
     Kansas, Museum of Natural History.

     =Arkansas.= _Boone County_: 3 mi. E Bergman, 4[74]; 3 mi. SE
     Bergman, 1[74]; 3 mi. S Bergman, 1[74]; 3 mi. SW Bergman, 1[74]; 4
     mi. SE Bergman, 2[74]; 5 mi. SE Bergman, 1[74]; 4-1/2 mi. SE
     Bergman, 3[74]; 5 mi. SE Bergman, 1[74]; 5 mi. S Bergman, 2[74]; 5
     mi. SW Bergman, 2[74]. _Washington County_: Fayetteville, 1[96].
     _Crawford County_: 10 mi. S Winslow, 1. _Sebastian County_: Fort
     Smith, 1[91].

     =Iowa.= _Fayette County_: Fayette, 3[12]. _Dubuque County_:
     Dubuque, 1[12]; Green's Island, 1[65]. _Butler County_: New
     Hartford, 1[12]. _Hardin County_: Union, 1[65]. _Benton County_:
     Vinton, 5[12]. _Linn County_: Cedar Rapids, 1[12]. _Boone County_:
     Worth Township, Sec. 21, 1[65]; 2 mi. E Ledges St. Park, 1[65].
     _Story County_: Kelley, 1[65]. _Cedar County_: Tipton, 3[12].
     _Scott County_: Davenport, 2[12]. _Muscatine County_: Muscatine,
     4[12]. _Henry County_: Hillsboro, 5[91]. _Van Buren County_:
     Keosaqua, 1[65]; no locality more definite than county, 1[50].
     _Taylor County_, 1.

     =Kansas.= _Riley County_: near Winkler, 1. _Pottawatomie County_:
     Onaga, 1[83]. _Atchison County_: Doniphan Lake, 1; 5 mi. NE
     Muscotah, 1; no locality more definite than county, 1. _Douglas
     County_: Lawrence, 8; 6 mi. NW Lawrence, 1; 1-1/2 mi. W Lawrence,
     1; 6 mi. S Lawrence, 1; 7 to 7-1/2 mi. SW Lawrence, 14; 10 mi. W
     Lawrence, 1; Clinton, 4; Baldwin, 1; no locality more than county,
     29 (2[74]). _Woodson County_: 1-1/2 mi. S Neosho Falls, 1[59].
     _Greenwood County_: 8 mi. SW Toronto, 2. _Pratt County_: Pratt, 1.

     =Louisiana.= _Quachita Parish_: Swartz, 1[71].

     =Missouri.= _Carroll County_: Bridge Creek, 1[91]. _Lincoln
     County_: Silex, 1[74]; 1 mi. E Silex, 1[74]. _Reynolds County_: 4
     mi. S Lesterville, 1[74]. _Jasper County_: 5 mi. NE Avilla, 1[91];
     7-1/2 mi. SE Carthage, 1[74].

     =Oklahoma.= _Payne County_: 8 mi. NW Stillwater, 1[82]. _Cleveland
     County_: Norman, 1[100].

     =Texas.= _Hopkins County_: 10 mi. S Sulphur Springs, 1[43].


=Mustela frenata arthuri= Hall

Long-tailed Weasel

Plates 16, 17 and 18

    _Mustela noveboracensis arthuri_ Hall, Proc. Biol. Soc. Washington,
      40:193, December 2, 1927.

    _Mustela frenata arthuri_ Hall, Carnegie Instit. Washington Publ.
      473:105, November 20, 1936.

     _Type._--Male, subadult, skull and skin; no. 37515, Mus. Vert.
     Zoöl.; Remy, St. James Parish, Louisiana; December 15, 1926;
     obtained by Stanley C. Arthur.

     The skin is stuffed and well preserved. The skull (plates 16-18)
     is unbroken. The teeth all are present and entire. The presence of
     a well-developed scrotal pouch shows the specimen to be a male.
     Contrary to what was stated in the original description the
     specimen was taken in 1926 and not in 1925.

     _Range._--Lower Austral Life-zone of southeastern Texas,
     Louisiana, and into Mississippi. See figure 29 on page 221.

     _Characters for ready recognition (of males)._--Differs from _M.
     f. olivacea_ in smaller size (adult males with hind foot and
     basilar length less than 45), depth of skull at anterior margin of
     basioccipital, ignoring sagittal crest, amounting to more than 63
     per cent of mastoid breadth, and greater convexity of dorsal
     outline of skull in longitudinal axis (see pls. 16-18); from _M.
     f. noveboracensis_, in males, by zygomatic breadth not less than
     distance between anterior palatine foramen and anterior margin of
     tympanic bulla and by convex dorsal outline of skull in
     longitudinal axis; from _M. f. primulina_ by evenly spreading
     zygomatic arches, lesser inflation of tympanic bullae
     anteromedially than posteromedially, and convex dorsal outline of
     skull in longitudinal axis; from _M. f. texensis_ and _M. f.
     frenata_ by absence of white facial markings and postorbital
     breadth more than distance between posterior borders of P4 and P2.

     _Description._--_Size._--Male: The type, a subadult male, measures
     (inches and quarter fractions thereof, transposed into
     millimeters) as follows: Total length, 390; length of tail, 113;
     length of hind foot, 44. Tail is 41 per cent as long as head and
     body. Length of hind foot less than basal length.

     Typical female unknown.

     _Externals._--Longest facial vibrissae black, or dark brown (both
     colors in the type) and extending beyond ear; carpal vibrissae
     same color as underparts and extending to within 3.5 millimeters
     of apical pad of fifth digit. Hairiness of foot-soles in type
     slightly less than shown in figure 20.

     _Color._--Upper parts in summer tone 4 of Burnt Umber of Oberthür
     and Dauthenay, pl. 304; underparts as described in _M. f.
     olivacea_. In winter, upper parts (based on type) near (1)
     Brussels Brown or grayer than tone 4 of Burnt Umber of Oberthür
     and Dauthenay, pl. 304, darker on top of head from nose to a line
     connecting posterior margins of ears. Chin and posterior third of
     each upper lip white. Remainder of underparts white with wash of
     Warm Buff. Tip of tail black. Color of underparts extends distally
     on posterior sides of forelegs over toes but represented on
     antipalmar faces of feet by only a few scattered hairs. Color of
     underparts extends distally on medial sides of hind limbs only to
     knees. Least width of color of underparts amounting to 15 per cent
     of greatest width of color of upper parts. Black tip of tail 50
     mm. long; thus longer than hind foot and 44 per cent as long as
     tail-vertebrae.

     _Skull and teeth._--Male (based on type and 2 subadults): See
     measurements and plates 16-18. As described in _M. f.
     noveboracensis_ except that: Weight, 4.0 (3.7-4.3) grams; basilar
     length, 43.5 (43.3-43.6); zygomatic breadth not less than distance
     between anterior palatine foramen and anterior margin of tympanic
     bulla; postorbital breadth more than length of upper premolars;
     interorbital breadth more than distance between foramen opticum
     and anterior margin of tympanic bulla; least width of palate more
     or less than length of P4; tympanic bulla longer than rostrum.

     Female: Typical skull unknown. The skull from 12 miles east of
     Eagle Lake, Texas, lacks the convexity in the dorsal longitudinal
     axis and the skull agrees with those of larger individuals of
     _primulina_ except that the anteromedial faces of the tympanic
     bullae are less inflated, and the mastoid and zygomatic breadths
     are greater than in any female seen of _primulina_. Probably this
     greater breadth is the result of intergradation with _M. f.
     frenata_ to the westward.

Compared with the skull of _M. f. olivacea_ that of _arthuri_ differs
as follows: Averaging smaller in every part measured; basilar length 5
mm. less; by weight a fourth lighter; relative to basilar length,
interorbital breadth greater and zygomatic and especially mastoid
breadth less; dorsal outline of skull more convex in longitudinal axis;
tympanic bullae narrower and less inflated especially on anteromedial
faces. Compared with the skull of _noveboracensis_ that of _arthuri_
has the zygomatic breadth equal to or exceeding the distance from the
anterior palatine foramen to the anterior margin of the tympanic bulla,
whereas the zygomatic breadth is less than this distance in
_noveboracensis_. Also, in _arthuri_, the rostrum is relatively
shorter, the braincase is more inflated anteriorly, the zygomatic
arches are more uniformly spreading, and the dorsal outline of the
skull is distinctly convex, both transversely and longitudinally,
whereas it is transversely more nearly flat in _noveboracensis_ and
longitudinally is concave in the interorbital region.

Compared with _M. f. primulina_, _arthuri_ has narrower bullae, which
are much less inflated on their anteromedial faces, a less marked
postorbital constriction, a braincase which is narrower across the
mastoid region and broader anteriorly, and a skull, which, in
longitudinal axis, has the dorsal outline markedly more convex.

Compared with the skull of _M. f. texensis_ that of _arthuri_ is
smaller in every part measured; length one-fifth less; one-half as
heavy; postorbital constriction less marked; braincase relatively
narrower posteriorly and tympanic bullae less inflated especially
anteromedially. Compared with the skull of _M. f. frenata_ that of
_arthuri_ is smaller in every part measured; basilar length 6 mm. less;
a third lighter; postorbital constriction less marked; relative to the
basilar length the rostrum is broader, longer and deeper; the zygomatic
expanse and breadth of the braincase across the mastoids is less; the
dorsal profile of the skull is more convex in longitudinal axis;
zygomata evenly spreading rather than abruptly protruding from skull
posteriorly; tympanic bullae less inflated anteromedially.

_Remarks._--In 1926, Stanley C. Arthur, then Director of the Division
of Wild Life, for the Louisiana State Department of Conservation,
obtained specimens of this weasel. Some of them were mounted and the
remainder were placed in the collections of the United States National
Museum and the Museum of Vertebrate Zoölogy. In 1938 to 1940 George H.
Lowery saved specimens from Baton Rouge, which showed the color of the
summer pelage and revealed that the size of males was more than was
indicated by the original materials. In 1940 and 1941 Rollin H. Baker
obtained specimens from eastern Texas which greatly extended the known
geographic range.

In addition to the localities represented by specimens examined, Arthur
(1928:117) has recorded specimens from Greensburg, St. Helena Parish;
Braithwaite, Plaquemines Parish; Geismar, Assumption Parish; Laurel
Hill, West Feliciana Parish; French Settlement, Livingston Parish; and
Kentwood, Tangipahoa Parish. All these localities lie within the
eastern half of southern Louisiana. A skin-only, no. 38902, Mus. Vert.
Zoöl., obtained from a fur buyer by Stanley C. Arthur, was taken in
Mississippi "south of Jackson." Possibly it is of the subspecies
_arthuri_.

Intergradation with _M. f. olivacea_ is indicated by a specimen from
Mobile County, Alabama, commented on in the account of _olivacea_.
Intergradation with _primulina_ is indicated by the shape of the
anteromedial part of the bullae of the specimen from Swartz, Louisiana,
that is referred to _primulina_. The lack of specimens from the
northern two-thirds of Mississippi and from western Tennessee, prevents
any definite statement as to the limits of range of _arthuri_ in those
areas. In comparison with animals from the type locality, the slightly
larger size of the adult male from Baton Rouge, and the still larger
size of the adult male of _primulina_ from Swartz, Louisiana, suggests
that the _olivacea_ "influence" may extend farther west in the
latitude of northern Louisiana than anywhere else.

None of the skulls examined shows malformation of the frontal sinuses
such as results from infestation by parasites in some races. Arthur
(1928:115) speaks of the ". . . cut-over swamp land, where the tupelo
and cypress have been removed, . . ." as constituting suitable habitat
for this animal.

     _Specimens examined._--Total number, 13, as follows:

     =Texas.= _Colorado County_: 12 mi. N Eagle Lake, 1[43]; 5 mi. W
     Eagle Lake, 1[43]; 3 mi. S Garwood, 1[43].

     =Louisiana.= _East Baton Rouge Parish_: Baton Rouge, 4[71].
     _Livingston Parish_: Springville, 1[74]. _Saint James Parish_:
     Convent, 1[91]; Remy, 2 (1[74], 1[45]). _Assumption Parish_: near
     Lake Verret, 1[45].

     =Mississippi.= _Harrison County_: Saucier, 1[71].


=Mustela frenata olivacea= Howell

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

    _Mustela peninsulae olivacea_ Howell, Proc. Biol. Soc. Washington,
      26:139, May 21, 1913.

    _Mustela frenata olivacea_, Hall, Carnegie Instit. Washington Publ.
      473:104, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 180802, U. S. Nat. Mus.,
     Biol. Surveys Coll.; Autaugaville, Autauga County, Alabama;
     December 22, 1912; obtained by L. S. Golsan.

     The skull (plates 16-18), although cracked at two places in the
     interorbital region, is in one piece and not warped out of shape.
     The teeth all are present and entire. The skin is exceptionally
     well made and in perfect condition except for the extreme tip of
     the tail which is broken off.

     _Range._--Lower and Upper Austral life-zones in eastern
     Mississippi, Alabama, Georgia, South Carolina, and northern
     Florida. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     peninsulae_ in finer, softer pelage and shorter (less than 15.8 in
     ad. [F]) tympanic bullae; from _M. f. noveboracensis_, in adult
     males by wider tympanic bulla which is more than rather than less
     than 8.5, in adult females by total length which is more than
     rather than less than 345, and by mastoid breadth which is more
     than rather than less than distance between articular faces of
     exoccipital condyle and glenoid fossa; from _M. f. arthuri_ in
     larger size (adult males with hind foot and basilar length each
     more than 45); depth of skull at anterior margin of basioccipital,
     ignoring sagittal crest, amounting to less than 63 per cent of
     mastoid breadth, and lesser convexity of dorsal outline of skull
     in longitudinal axis (See pls. 16-18).

     _Description._--_Size._--Male and female: External measurements
     of adults are available as follows:

                                                Length    Length
  Catalogue   Sex        Locality        Total     of     of hind
     no.                                length   tail      foot
      47165  [M]   Box Springs,           454     160        48
                          Talbot Co., Georgia

      47166  [M]   Box Springs,           435     147        47
                          Talbot Co., Georgia

      47167  [M]   Box Springs,           422     145        45
                          Talbot Co., Georgia

      41023  [M]   Thomas Co.,            443     140        47
                          Georgia

      41025  [M]   Grady Co.,             395     142        47
                          Georgia

     223880  [M]   Okefinokee Swamp,      416     145        49
                          Georgia

        198  [M]   Okefinokee Swamp,      425     140        48
                          Georgia

  Average 7  [M]                          427     146        47

      49385  [F]   Gainesville,           396     124        45*
                          Alachua Co., Florida

      41024  [F]   Thomas Co.,            380     125        41
                          Georgia

      51527  [F]   Talbot Co.,            376     128        43
                          Georgia
  * [not typical]

     The length of the hind foot averages less than the basal length in
     both males and females. The tail averages 52 per cent as long as
     the head and body in males and 51 per cent in females. Average
     differences in measurements of the two sexes are: Total length,
     49; length of tail, 19; length of hind foot, 5. An adult male, no.
     41023, and an adult female, no. 41024, each taken in February,
     1929, on the Sinkola Plantation, Thomas County, Georgia, weighed
     15 ounces (425 grams) and 7 ounces (198 grams) respectively
     according to Charles O. Handley.

     _Externals._--As described in _Mustela frenata noveboracensis_,
     except that hairiness of foot-soles slightly less than shown in
     figure 19.

     _Color._--Upper parts, in summer, near tone 4 of Burnt Umber of
     Oberthür and Dauthenay, pl. 304. In winter lighter, between tones
     3 and 4 of Raw Umber of Oberthür and Dauthenay, pl. 301. Dark spot
     at each angle of mouth present or absent. Underparts ranging from
     Massicot Yellow to Cream Buff except on chin and upper lips which
     are white. Tip of tail black. Upper parts of uniform color. Color
     of underparts extends distally on posterior sides of forelegs over
     antipalmar faces of toes and on medial sides of hind limbs to
     ankles. Least width of color of underparts averaging, in a series
     of five males from Talbot Co., Georgia, 29 (extremes 24-34) per
     cent of greatest width of color of upper parts. Black tip of tail
     in same series, averaging 65 (extremes 60-70) mm. long, thus
     longer than hind foot and averaging 43 per cent of length of
     tail-vertebrae.

     The spot at the angle of the mouth is absent in one-third of the
     specimens examined. The upper lips are white in specimens from the
     southern part of the range of _olivacea_ but in the northern part
     of the range of the subspecies the upper lips are dark colored as
     in _noveboracensis_.

     _Skull and teeth._--Male (based on 5 adults from Talbot Co.,
     Georgia): See measurements and plates 16-18; weight, 5.3 (5.0-6.4)
     grams; basilar length, 48.3 (45.8-50.1); zygomatic breadth more or
     less (usually less) than distance between condylar foramen and M1
     and more or less (usually more) than distance between anterior
     palatine foramen and anterior margin of tympanic bulla; mastoid
     breadth more or less than (averaging about equal to) postpalatal
     length; postorbital breadth less than length of upper premolars
     and more or less than (about equal to) width of basioccipital
     measured from medial margin of one foramen lacerum posterior to
     its opposite; interorbital breadth more or less than (about equal
     to) distance between foramen opticum and anterior margin of
     tympanic bulla; breadth of rostrum less than length of tympanic
     bulla; least width of palate less than greatest length of P4;
     anterior margin of tympanic bulla as far posterior to foramen
     ovale as width of 3 to 5 upper incisors; height of tympanic bulla
     not less than distance from its anterior margin to foramen ovale;
     length of tympanic bulla more than length of lower molar and
     premolar tooth-row and longer than rostrum (one exception);
     anterior margin of masseteric fossa below posterior half of m2.

     Female (based on 2 adults from Thomas Co., Ga., and one from
     Talbot Co., Ga.): See measurements and plates 31-33; weight, 3.8
     (3.5-4.0) grams; basilar length, 43.4 (42.7-44.0); zygomatic
     breadth less than distance between condylar foramen and M1 or than
     between anterior palatine foramen and anterior margin of tympanic
     bulla; postorbital breadth less than length of upper premolars and
     more or less (usually more) than width of basioccipital measured
     from medial margin of one foramen lacerum posterior to its
     opposite; least width of palate less than greatest length of P4;
     tympanic bulla as far posterior to foramen ovale as width of 3 to
     4 (including I3) upper incisors; height of tympanic bulla not less
     (usually more) than distance from its anterior margin to foramen
     ovale; length of tympanic bulla more than length of lower molar
     and premolar tooth-row and longer than rostrum.

     The skull of the female averages 28 per cent lighter than that of
     the male.

Compared with the skull of _M. f. peninsulae_, of which only one good
skull, and that a female, is available, that of _M. f. olivacea_
averages smaller and has relatively and actually smaller and less
inflated bullae. As compared with the skull of _M. f. noveboracensis_,
that of _olivacea_ in the case of males is larger in every part
measured and relative to the basilar length is broader across the
zygomatic arches and mastoids. However, the rostrum and interorbital
region are relatively narrower. The orbitonasal length is relatively
less. The tympanic bullae are broader and more inflated. The same
differences hold as between females of _noveboracensis_ and _olivacea_.
Indeed, the females of these two races differ more than do the males.
Additional, selected differential cranial characters in the females
are, in _olivacea_, as follows: Weight averaging 3.8 grams rather than
1.7 grams; braincase with, rather than without, sagittal crest;
anterior border of tympanic bulla separated from foramen ovale by
breadth of less than, rather than breadth of more than, 4 upper
incisors (including I3); height of tympanic bulla not less than, rather
than less than, distance from its anterior margin to foramen ovale;
squamosal bone, between anterior margin of tympanic bulla and foramen
ovale, ventrally concave rather than ventrally convex. Comparisons of
the skulls with those of _M. f. arthuri_ and _M. f. primulina_ are made
in the accounts of those subspecies.

_Remarks._--Excepting two young specimens from South Carolina in the
Charleston Museum, no specimens of this race of large weasel seem to
have been preserved until Arthur H. Howell, in the course of his study
of the mammals of Alabama, procured specimens on which his name,
_olivacea_, was based. Later, Francis Harper obtained three instructive
specimens from Okefinokee Swamp. Really adequate material, for the
localities represented, owes its preservation to the alertness of
Charles O. Handley, when he resided at Thomasville, Georgia, and to
Hallie E. Fuller of Geneva, Talbot Co., Georgia.

The distinctness of _M. f. olivacea_ from _M. f. peninsulae_ is not
satisfactorily established due to inadequate material of _peninsulae_.
Differences shown by the specimens seen indicate that, as compared with
_olivacea_, _peninsulae_ is larger, has transversely wider
light-colored underparts which possess more yellow, and a larger skull
with more inflated tympanic bullae. In each of these characters,
_olivacea_ is intermediate between _noveboracensis_ on the north and
_peninsulae_ on the south. The question arises, therefore, whether the
animals here recognized under the name _olivacea_ really constitute a
recognizable subspecies or instead are only representatives of a
subspecies which reaches its extreme development in Florida. In the
latter event, the name _peninsulae_ would apply to all. Examination of
more material from Florida, especially from the southern half of
Florida, will be necessary to answer this question.

This large weasel of the southeastern United States is remarkably
different from _noveboracensis_. Indeed, were it not for actual
intergrades such as the two from Fort Payne, Alabama, and York, South
Carolina, which are described in the account of _M. f. noveboracensis_,
and the six specimens from northwestern Alabama, which are referred to
_olivacea_, the systematist, I believe, would have little or no
hesitancy in designating the two as distinct species, especially on the
basis of differences to be seen in the skull.

Not only are the two forms structurally more different than usually is
the case but between two geographically, adjacent subspecies of the
same species of mammal, but the belt where intergradation occurs
appears to be narrow. Nevertheless, when material of the two races is
laid out in geographic order, and examined in mass, certain features
are seen to undergo gradual change as a person's eye travels from
specimens from, say, the center of the range of _noveboracensis_ to
specimens from southern localities adjoining the territory occupied by
_olivacea_. One of these features subject to gradual change is the
color of the underparts. Beginning at the Adirondacks of New York
where a large number of the specimens have white underparts, the
underparts become more intensely yellowish southward through the range
of _noveboracensis_ into that of _olivacea_. Indeed, this progressive
trend seems to continue right on southward through the range of
_olivacea_ into that of _peninsulae_. Turning in the opposite direction
we find that the least width of the underparts decreases gradually
northward toward the range of _noveboracensis_. There is, likewise, a
decrease to the northward in length of the skull and relative, as well
as actual, narrowing of the braincase and tympanic bullae. However, in
least width of color of underparts and the mentioned cranial features,
the trend stops relatively abruptly at the southern boundary of the
geographic range of _noveboracensis_ and does not continue on,
northward, into the range of _noveboracensis_ as is the case with the
change in intensity of yellowness of the underparts.

Two males, in the United States National Museum, Biological Surveys
Collection, from near Leighton, Alabama, no. 178386 from the Tennessee
River nine miles north [of Leighton?] and no. 180240 from La Grange
Mountain, although clearly referable to _olivacea_ on the basis of
cranial characters, show some approach to _noveboracensis_ in lesser
size of the skull and agree with _noveboracensis_ in the narrowness of
the color of the underparts. Also, these specimens, like others from
the northern part of the range of _olivacea_, for instance, no 31.227,
Charleston Museum, from Mayesville, South Carolina, have the color of
the underparts extended only part way out on the hind limb toward the
foot. In specimens of _olivacea_ from the southern part of its range
the color of the underparts is extended onto the hind feet and this
trend reaches its extreme in _peninsulae_, specimens of which have the
feet and larger parts of the limbs marked with the light color of the
underparts.

An adult female, no. 32.32, Charleston Museum, although typical of
_olivacea_ in most respects, is nevertheless an intergrade. The teeth
are as small as in some specimens of _noveboracensis_. The size of the
skull is only slightly nearer that of _olivacea_ than it is to that of
_noveboracensis_. The proportions of the skull, however, are distinctly
those of _olivacea_.

Five other specimens, from northwestern Alabama, namely two from eight
miles north of Nauvoo, two from Shoal Creek, and one from White Creek,
also show intergradation between _noveboracensis_ and _olivacea_. The
remarks concerning color and color pattern of the specimens from
Leighton apply equally well to the five from northwestern Alabama. In
cranial characters, no. 51658 from Shoal Creek is referable to
_olivacea_, as also is no. 51677 from the same place, providing it is a
female rather than a male as sexed by the collector. No. 57146 from
White Creek also is referable to _olivacea_ although the skull shows
some approach to that of _noveboracensis_. Of the two males from near
Nauvoo, no. 51652 is to me indistinguishable from _noveboracensis_, but
no. 51653 does have some characters of _olivacea_, although on the
whole, the latter, too, seems to be a little nearer _noveboracensis_
than _olivacea_. However, because the mean of these seven specimens
from northwestern Alabama is nearer _olivacea_ than _noveboracensis_
the former name may be applied.

Another specimen from "Souinlonie" Creek, Clark County, Mississippi,
has the coloration and rostral configuration of _primulina_, narrow
mastoidal breadth and smaller teeth of _noveboracensis_ and skull of
large size with "full" braincase as in _olivacea_. No. 235364, U. S.
Nat. Mus., from the Mobile River at the "L. and N. RR. Crossing,"
Mobile County, Alabama, although definitely _olivacea_, shows approach
to _arthuri_ in that the dorsal outline of the skull is longitudinally
more convex and the tympanic bullae are less inflated than in
_olivacea_ and in that the color of the underparts is almost exactly as
in the type specimen of _arthuri_. The young specimen labeled as from
"Silver Springs," Florida, has large tympanic bullae (17 mm. long) and
several characters that show its relationship to _peninsulae_ as that
race is now understood. Because the sex is unknown the identification
as _olivacea_ is tentative and is made on the assumption that the
specimen is a male. If it is instead a female, the animal is referable
to _peninsulae_.

An adult, female specimen in the Charleston Museum, no. 27.239.1, taken
at St. Matthews, South Carolina, on December 8, 1927, contained four
embryos which averaged 19 mm. in length and 47.75 centigrams in weight.
Another adult female, in the Charleston Museum, no. 32.32, taken on
February 21, 1932, at the same place, has prominent mammae, and the
collector has noted that two were slightly active.

Sixteen of twenty-nine adults examined show infestation of the frontal
sinuses by parasites. However, in none is the malformation of the
frontal region so great as frequently occurs in _M. f. noveboracensis_.

     _Specimens examined._--Total number, 52, arranged alphabetically
     by states and from north to south by counties in each state.
     Except as otherwise indicated specimens are in the University of
     California Museum of Vertebrate Zoölogy.

     =Alabama.= _Lawrence County_: White Creek, 1; Little Sand Mt.,
     Shoal Creek, 2. _Winston County_: 7-1/2 mi. N Nauvoo, 1; 8 mi. N
     Nauvoo, 1. _Lauderdale County_: near Leighton, 9 mi. N Tennessee
     River, 1[91]. _Colbert County_: Leighton, 1[91]. _Autauga County_:
     Autaugaville, 1[91]. _Dale County_: Midland City, 1[91]. _Mobile
     County_: Mobile River, 12 mi. NE Mobile, 1[91].

     =Florida.= _Alachua County_: Gainesville, 4[61]. _Marion County_:
     "Silver Springs," 1.

     =Georgia.= _Spalding County_, 1. _Lamar County_, 1. _Talbot
     County_: southwest part of county, 1; Box Springs, near Geneva, 3;
     Upatoie Creek, 1 mi. SW Box Springs, 2; 3 mi. SE Geneva, 1; 4 mi.
     W Geneva, 1; 5 mi. W Geneva, 1; 2 mi. E Geneva, 1. _Chattahoochee
     County_, 2. _Grady County_: Beachton, 3[91]; locality no more
     definite than county, 4. _Thomas County_: Sinkola Plantation, 2;
     locality no more definite than county, 2. _Charlton County_: 1/2
     mi. E Chesser's Island, Okefinokee Swamp, 1[58]. _County_ in
     question: Billy's Island, Okefinokee Swamp, 1[91]; Okefinokee
     Swamp, 1[58].

     =Mississippi.= _Clark County_: Souinlonie Creek, 1.

     =South Carolina.= _Darlington County_: Society Hill, 1[91].
     _Sumter County_: Mayesville, 1[11]. _Calhoun County_: St.
     Matthews, 2[11]. _Georgetown County_: Sampit, 1[11]. Charleston
     County: Rantowles, 1[11]; 8 mi. N Charleston, 1[11]. _Beaufort
     County_: Yemassee, 1[2].


=Mustela frenata peninsulae= (Rhoads)

Long-tailed Weasel

Plates 16, 17 and 18

    _Putorius peninsulae_ Rhoads, Proc. Acad. Nat. Sci. Philadelphia,
      1894:152, June 19, 1894; Bangs, Proc. Biol. Soc. Washington,
      10:10, February 25, 1896.

    _Mustela peninsulae_, Miller, U. S. Nat. Mus. Bull., 79:98,
      December 31, 1912.

    _Mustela p. peninsulae_, Bailey, Bailey Mus. and Library Nat.
      Hist., 1(no. 5):1, December 1, 1930.

    _Mustela frenata peninsulae_, Hall, Carnegie Instit. Washington
      Publ. 473:105, September 20, 1936.

     _Type._--Female, young, part skull and skin; no. 8515, Acad. Nat.
     Sci. Philadelphia; Hudson's, Pasco County [14 miles north of
     Tarpon Springs], Florida; before 1895; obtained by W. S.
     Dickinson.

     The skull has been cut vertically in two at the plane of the
     glenoid fossae. These fossae and all the cranium posterior to them
     are missing. In addition to the part of the cranium anterior to
     the glenoid fossae, the lower jaws are preserved complete. The
     teeth all are present and entire. The prominent sutures on the
     rostrum and palate show the specimen to be young and its small
     size leaves but little doubt that the animal was a female. The
     light facial markings are more extensive than in any of the
     referred specimens. In the type these light facial markings
     consist of a median isolated spot immediately in front of the
     ears, a larger one on the nose, with an interrupted bar on each
     side extending posteroventrally in front of and anterior to the
     eye, a wider bar, on each side, extending anterodorsally between
     the ear and eye and finally an isolated spot at the anterior
     border of each ear. The skin is stuffed and in fair condition
     except that the vertebrae remain in the tail.

     _Range._--Austral and probably Tropical life-zones of Florida
     south of latitude 29°. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     olivacea_ in coarser pelage and larger tympanic bullae.

     _Description._--_Size._--Male: No external measurements available.
     Female: The type a young animal and no. 2379, an adult from Tarpon
     Springs, measure respectively as follows: Total length, 375, 378;
     length of tail, 100, 130; length of hind foot, 40, 44.5.

     _Externals._--As described in _Mustela frenata noveboracensis_
     except that hairiness of foot-soles as shown in figure 20.

     _Color._--Upper parts (in winter) near tone 3 of Burnt Umber of
     Oberthür and Dauthenay, pl. 304. Dark spot at each angle of mouth
     present or absent. Tip of tail black. Underparts Reed Yellow
     except on chin and usually on legs where white. Upper lips white
     entirely around. Upper parts of uniform color. Color of underparts
     extends distally on legs over both sides of feet and on front legs
     over wrists. Proximal part of tail slightly lighter below than
     above. Least width of color of underparts, in seven specimens,
     averaging 41 (extremes 31-52) per cent of greatest width of color
     of upper parts. Black tip of tail, in each of two females, 45 mm.
     long; thus slightly longer than hind foot and amounting to 36 per
     cent of length of tail-vertebrae.

     The spot at the angle of the mouth is absent in four of the ten
     specimens and is present on both sides in the other six.

     _Skull and teeth._--Male (based on an adult from Apopka and the
     anterior part of an adult from Enterprise): See measurements and
     plates 16-18. As described in _Mustela frenata olivacea_ except
     that: Weight, 7.0 grams; basilar length, 49.8.

     Female (based on an adult from Tarpon Springs, Florida): See
     measurements. As described in _Mustela frenata olivacea_ except
     that: Weight, 4.7 grams; basilar length, 44.2; zygomatic breadth
     more than distance between anterior palatine foramen and anterior
     margin of tympanic bulla.

In comparison with _M. f. olivacea_, the insufficient material of _M.
f. peninsulae_ suggests that its skull averages larger and has
relatively as well as actually larger and more inflated tympanic
bullae.

_Remarks._--The first published mention of this weasel seems to have
been the original description which appeared in 1894. This description
was based on a single specimen sent to Samuel N. Rhoads by W. S.
Dickinson, who, in the following year, procured another specimen at
Tarpon Springs. So far as known only eight other specimens, as listed
under "_Specimens examined_," have found their way into collections of
study specimens.

H. H. Bailey (1930:1) credits the range of this subspecies as extending
south "to the shores of Florida Bay and the Gulf of Mexico, where ever
high ground occurs."

Evidence of intergradation between _M. f. peninsulae_ and _M. f.
olivacea_ is provided by specimens of _olivacea_ from Gainesville,
Florida, and the Okefinokee Swamp, Georgia. These specimens, on the
average, have the color of the underparts wider, the skull larger, and
the tympanic bullae relatively larger than do specimens of _olivacea_
from farther north. In these features, approach to _M. f. peninsulae_
is shown.

Light facial markings occur in this subspecies. They are similar to
those possessed by weasels which occur at the same latitude and under
corresponding climatic conditions on the Pacific Coast. The type
specimen and one from Tarpon Springs have white facial markings. Two of
the three specimens from Apopka also show white facial markings,
although in reduced amount. One of the four specimens of _M. f.
olivacea_ from Gainesville, Florida, has well-developed light (white)
facial markings. Also of the four specimens of _M. f. olivacea_
examined from Okefinokee Swamp, Georgia, one has prominent white facial
markings. However, in it the pattern is so unusual as to suggest that
it is an instance of partial albinism rather than an outcropping of a
racial tendency, or a pattern of coloration induced by climatic
factors.

None of the eight available skulls show any infestation of the frontal
sinuses by parasites.

     _Specimens examined._--Total number, 10, arranged by counties from
     west to east.

     =Florida.= _Pasco County_: Hudson's, 1[1]. _Pinellas County_:
     Tarpon Springs, 1[1]. _Hernando County_, 1[91]. _Polk County_:
     Auburndale, 1[91]; no locality more definite than county, 1[91].
     _Orange County_: Apopka, 3[61]. _Volusia County_: Enterprise,
     1[60]. _Seminole County_: Osceola, 1[2].


=Mustela frenata spadix= (Bangs)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

    _Putorius longicauda spadix_ Bangs, Proc. Biol. Soc. Washington,
      10:8, February 25, 1896; Merriam, N. Amer. Fauna, 11:21, figs.
      10, 11, June 30, 1896; Cory, Mamm. Illinois and Wisconsin, p.
      374, 1912.

    _Mustela longicauda spadix_, Miller, U. S. Nat. Mus. Bull., 79:98,
      December 31, 1912; Bailey, Journ. Mamm., 10:156, May 9, 1929.

    _Mustela longicauda_, Johnson, Journ. Mamm., 11:439, November 11,
      1930.

    _Mustela noveboracensis_, Murie, Journ. Mamm., 16:321, November 15,
      1935.

    _Mustela frenata spadix_, Hall, Carnegie Instit. Washington Publ.
      473:105, November 20, 1936.

     _Type._--Male, young, skull and skin; no. 3265/1786, Amer. Mus.
     Nat. Hist.; Fort Snelling, Hennepin County, Minnesota; June 25,
     1889; obtained by Edgar A. Mearns; original no. 812.

     The skull is complete although there are fractures on the top of
     the braincase, on the right side of the braincase and at the
     middle of the right zygomatic arch. The teeth all are present and
     entire. The skin, although overstuffed, is complete, well
     preserved, and in summer pelage.

     _Range._--Upper Austral and Transition life-zones of Minnesota,
     northern and western Iowa, southeastern North Dakota, eastern part
     of South Dakota, and northeastern Nebraska. See figure 29 on page
     221.

     _Characters for ready recognition._--Differs from _M. f.
     noveboracensis_ and _M. f. primulina_ in that specimens of all
     ages have least width of color of underparts amounting to more
     than 41 per cent of greatest width of color of upper parts, and
     have light color of underparts extended onto hind foot rather than
     stopped short of ankle; adults with hind feet more than 50 in
     males and 40 in females; orbitonasal length more than 15.5 in
     males and 13.5 in females; length of tooth-rows more than 18.0 in
     males and 15.7 in females; mastoid breadth more than 25.5 in males
     and 22.0 in females. From _M. f. longicauda_ by color darker than
     near (_h_) Clay Color, in males by a flattened occiput in which
     the depth of the skull, exclusive of the sagittal crest and taken
     at the anterior border of the basioccipital, amounts to less than
     58 per cent of the mastoid breadth.

     _Description._--_Size._--Male: Three adults from Elk River,
     Minnesota, yield average and extreme measurements as follows:
     Total length, 458 (444-467); length of tail, 154 (140-165); length
     of hind foot, 55 (52-59). Tail averages 51 per cent as long as
     head and body. Length of hind foot averages more than basal
     length. Corresponding measurements of three subadults from
     Madison, Minnesota, are as follows: 453 (438-469); 157 (152-165);
     50 (47-51). Tail averages 53 per cent as long as head and body.

     Female: Three adults from Elk River, Minnesota, yield average and
     extreme measurements as follows: Total length, 387 (380-391);
     length of tail, 131 (121-138); length of hind foot, 44 (43-46).
     Tail averages 51 per cent as long as head and body. Length of hind
     foot more or less than (approximately equal to) basal length.
     Corresponding measurements of two adults and one subadult from
     Madison, Minnesota, are as follows: 385 (379-396); 137 (119-159);
     42 (38-44). Tail averages 55 per cent as long as head and body.

     The average differences in external measurements of the two sexes
     from Elk River, are: Total length, 71; length of tail, 23; length
     of hind foot, 11. At Madison, corresponding differences are 68,
     20, and 8. Two adult females from Elk River, Minnesota, weigh 205
     and 210 grams.

     _Externals._--Longest facial vibrissae black, brown, or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles (in summer
     pelage) as shown in figure 19.

     _Color._--Winter pelage all white except tip of tail. In southern
     part of range sometimes assumes a brown winter coat. Summer pelage
     with upper parts ranging from near (16´) Cinnamon Brown to Vandyke
     Brown. Chin and upper lips white. Remainder of underparts ranging
     from near (a) Olive Ocher to Ochraceous Buff and Pale Orange
     Yellow. Tip of tail at all times black. Upper parts of uniform
     color except for occasional slight darkening of nose. Color of
     underparts extends distally on posterior sides of forelegs over
     toes onto antipalmar faces of feet and ankles, on medial sides of
     hind limbs to ankle, over antiplantar faces of toes and
     distomedial fourth of each tarsus, and over proximal fifth to
     third of under side of tail. Least width of color of underparts
     averaging (in 3 specimens from Elk River) 54 (47-59) per cent of
     greatest width of color of upper parts. Black tip of tail
     averaging same length as hind foot and 28 per cent of length of
     tail-vertebrae. Save for the greater width of the light-colored
     underparts and relatively short black tip of the tail, both
     features of _M. f. longicauda_, _spadix_ is variously
     intermediate, depending on locality, as between _noveboracensis_
     and _longicauda_.

     _Skull and teeth._--Male (based on 3 adults from Elk River,
     Minn.): See measurements and plates 16-18. As described in
     _Mustela frenata longicauda_ except that: Weight, 5.6 (5.0-6.5);
     basilar length, 49.0 (48.7-49.2); zygomatic breadth sometimes less
     than distance between anterior palatine foramen and anterior
     margin of tympanic bulla; postorbital breadth more or less (about
     equal to) width of basioccipital measured from medial margin of
     one foramen lacerum posterior to its opposite; interorbital
     breadth more or less than distance between foramen opticum and
     anterior margin of tympanic bulla; anterior margin of tympanic
     bulla as far posterior to foramen ovale as width of 4 to 5 upper
     incisors; height of tympanic bulla more or less than distance from
     its anterior margin to foramen ovale; length of tympanic bulla
     less than length of rostrum; anterior margin of masseteric fossa
     below talonid of m1.

     Female (based on 4 adults from Elk River, Minn.): See measurements
     and plates 31-33. As described in _Mustela frenata longicauda_
     except that: Weight, 3.5 (3.3-4.0) grams; basilar length, 42.9
     (42.3-43.2); least width of palate more or less than greatest
     length of P4; tympanic bulla as far posterior to foramen ovale as
     width of 3 to 5 upper incisors.

     The skull of the female averages 33 per cent lighter than that of
     the male.

Skulls of adult males of _spadix_ from Elk River, Minnesota, as
compared with those of _longicauda_ from Alberta, are larger in every
part measured. Relative to the basilar length these skulls of _spadix_
are broader across the mastoid region, narrower across the zygomata,
deeper through the plane of the postorbital processes, shallower
through the braincase and have relatively shorter tympanic bullae.
Whereas the tympanic bullae of _longicauda_ are, on the average,
approximately as long as the rostrum (orbitonasal length), in _spadix_
the rostrum is longer than the bulla. Viewed posteriorly, the braincase
of _spadix_ is seen to be much shallower and wider than that of
_longicauda_. Indeed, the depth of the braincase, measured at the
anterior end of the basioccipital, amounts to only 56 per cent of the
mastoid breadth in _spadix_ as against 61 per cent in _longicauda_. The
longer, waistlike, postorbital constriction, relatively smaller
braincase, and especially the relatively narrower zygomatic expanse in
_spadix_ imparts to its skull a more slender appearance than has the
skull of _longicauda_. These differences are not shown by the skulls of
females. To be sure, _spadix_, in most of its cranial measurements,
averages slightly larger, has a relatively shallower braincase and is
relatively deeper through the postorbital processes, but these
differences are so slight that inclusion of one more specimen, of
slightly different proportions, in the average might cause the average
measurements to read as they do in _longicauda_.

Compared with _noveboracensis_, from Massachusetts, adult skulls of
_spadix_, taking sex into account, are larger in every part measured
and are relatively as well as actually wider and deeper throughout.
Also, in _spadix_: Sagittal and lambdoidal crests higher, especially in
females; anterior margin of tympanic bulla projecting up sharply from
squamosal; occiput more flattened in posterior view; tooth-rows
relatively and actually longer but orbitonasal length relatively
shorter; postorbital processes more robust; zygomatic arches widely
bowed outward rather than evenly rounded; canines larger; squamosal
less swollen ventrally, especially in females. Between _noveboracensis_
and _spadix_, the differential cranial characters are greater in number
and degree between females than between males. Comparison of the skull
with that of _M. f. primulina_ is made in discussion of that
subspecies.

_Remarks._--Edgar A. Mearns in 1889 and the early nineties took several
specimens of this weasel and it was principally on these that Bangs in
1896 (p. 8) based his description. The best material, however, is that
from Elk River, Minnesota, collected in later years by Bernard Bailey,
and supplemented by one specimen taken in 1885 by Vernon Bailey and
another by his sister Anna Bailey in 1891 at the same place.

_Mustela frenata spadix_ has just one structural feature of a "unique"
kind which serves to differentiate it from the geographically adjoining
subspecies. This feature is large size. The other diagnostic characters
ascribed to _spadix_ are of an intermediate sort--intermediate as
between two extremes, one found to the westward in _longicauda_ and the
other to the eastward in _noveboracensis_. For example, the
dark-colored upper parts are merely darker than in _longicauda_ and
merely lighter than in _noveboracensis_. The color is not "different";
it is only "intermediate." Furthermore, each of the characters ascribed
to _spadix_, including large size itself, undergoes change from one
part of its geographic range to another; the characters are not
constant over a wide area. Indeed, excepting the large size which
remains relatively uniform over the northern two-thirds of the range,
no two localities have been found from which the specimens can be said
really to agree in characters.

By way of illustration, the coloration of the upper parts may be cited.
Near the range of _noveboracensis_ the average coloration of
individuals from one locality is only a little lighter than in
_noveboracensis_. Farther westward the average coloration is a little
lighter and farther westward yet, toward the range of the extremely
light colored _longicauda_, the average coloration is lighter still.
Although all these animals are darker than _longicauda_ and lighter
than _noveboracensis_, those from the three places do not agree among
themselves. Because of the lack of more than one character of a
"unique" kind and because of the inconstancy, geographically, of other
characters, and for that matter, lack of constancy geographically in
combination of characters, the writer regards _spadix_ as a barely
recognizable subspecies.

Examination of the specimens of _spadix_ shows that the individual
variation in a single species is greater in a region of intergradation
than it is some distance inside the borders of the geographic range of
a well-marked subspecies. This is illustrated by three specimens of _M.
f. spadix_ in fresh summer pelage from the single locality, Elk River,
Minnesota. In these, the color of the upper parts varies from a little
darker than Cinnamon Brown to Vandyke Brown. At any one locality well
within the range of _longicauda_, or _noveboracensis_, there is nowhere
nearly so much variation in color, even in much larger series of
specimens.

Study of the specimens here assigned to _spadix_ reveals that some
features regarded as of diagnostic value for one or the other of the
two races, _longicauda_ and _noveboracensis_, behave differently. For
example, the dark coloration of the upper parts, which is
characteristic of _noveboracensis_, manifests itself far westward
within the range of _spadix_ whereas the wider extent of the
light-colored underparts, which is characteristic of _longicauda_, and
the Olive Ocher, rather than Pale Orange Yellow, color of these
underparts, are seen in varying degree all the way across the range of
_spadix_. Thus, these animals are colored above like _noveboracensis_
and below like _longicauda_, but not _vice versa_. In these animals,
then, the _longicauda_ type of underparts is dominant, in one sense of
the word, over the _noveboracensis_ type of underparts, and the
_noveboracensis_ type of upper parts is dominant over the _longicauda_
type of upper parts. Each of these features is subject to actual
intergradation and does not always behave as a "unit character," that
is to say, one which is either present or absent. However, the
_noveboracensis_ type of upper parts is carried much farther west
before being diluted than is the _noveboracensis_ type of underparts.
Indeed, within the range of _noveboracensis_ itself, the broad extent
of the _longicauda_ type of underparts is manifest. This is, of course,
near the western margin of the range of _noveboracensis_.

The large size of males of _spadix_, as exemplified by specimens from
Elk River (see measurements on p. 421), seems to be retained across the
northern part of the range here assigned to the subspecies. This larger
size than is found in _longicauda_ from Alberta, is shown also by some
specimens from eastern North Dakota which are assigned to _longicauda_.
However, the average of these Dakotan specimens, all characters
considered, is nearer to my concept of _longicauda_.

Inspection of the cranial measurements of _spadix_ shows also that in
addition to its large size it is distinguishable from any one of the
geographically adjoining races by its relatively (to basilar length)
greater, as well as actually greater, mastoidal breadth. This might be
included with size as a unique character distinguishing _spadix_ from
_longicauda_ and _noveboracensis_. However, it is not clear whether or
not this greater mastoidal breadth is more than a function of the large
size.

Excepting the greater mastoidal breadth and generally larger size of
the skull, the cranial features distinguishing males of _spadix_ from
_longicauda_ are features in which _spadix_ shows approach to
_noveboracensis_. This is true, in _spadix_, of the relatively longer
(in comparison with _longicauda_) rostrum, relatively lesser zygomatic
breadth, relatively shallower braincase measured at the anterior end of
the basioccipital, and relatively deeper skull as measured at the
posterior borders of the last upper molars. This same approach to
_noveboracensis_ already has been pointed out with respect to color of
the upper parts and is evident also in the relative shortness of the
tail which averages only 51 per cent of the length of the head and body
rather than 55 per cent as in _longicauda_.

Because the _longicauda_ type of animal previously has been regarded as
specifically distinct from the _noveboracensis_ type of animal, comment
is offered below on selected specimens, referred to _spadix_, which are
regarded as intergrades with _noveboracensis_ or with other subspecies.

No. 8722, Univ. Wisconsin, adult male, in the white winter coat, from
north central Itasca County, Minnesota, obviously has characters of _M.
f. spadix_ or _longicauda_ that occur to the west and _M. f.
noveboracensis_ of the east. Selected outstanding characters of
_longicauda_ are its long tail, anteriorly truncate tympanic bullae
and large teeth. Characters indicating its affinities with
_noveboracensis_ are smaller size of skull, general narrowness of
skull, and relatively low tympanic bullae. The skull is intermediate as
regards several individual structural features. For example, although
long and narrow and in this feature more nearly approaching
_noveboracensis_, the skull is wider than usual in that subspecies and
thus approaches that of _longicauda_ or _spadix_. The hind foot, in the
dried state, measures 47 millimeters. This large hind foot, obviously
long tail (the specimen lacks external measurements), and anteriorly
truncate bullae constitute basis for here referring the specimen to
_spadix_. However, the seemingly small size of the body and the narrow
skull clearly show relationship to _noveboracensis_.

Specimens, referred to _spadix_, from northern Iowa, are instructive as
showing what happens where the ranges of _noveboracensis_, _primulina_,
_spadix_, and perhaps _longicauda_, meet. No. 47167, Univ. Mich. Mus.
Zoöl., a nearly adult female, taken on November 22, 1915, at Island,
Clay County, and in process of assuming a brown winter pelage, retains
enough of the dark summer pelage to show that the color was slightly
lighter than average for _spadix_. The color pattern, white lips, and
extension of light color of the underparts onto the feet, agrees with
_spadix_ or _longicauda_ as does also the long tooth-row. The overall
length of the skull is intermediate between that of _spadix_ and
_primulina_. The proportions of the anterior part of the skull and of
the tympanic bullae resemble those found in _primulina_. A subadult
male skull only, no. 123846, American Museum of Natural History, from
Webb, Clay County, shows approach to _primulina_ in the narrowness of
the rostrum.

A young male from Ruthven, Iowa, no. 48340, Univ. Michigan, has a large
skull approaching in size that of _spadix_, has the _longicauda-spadix_
type of light-colored underparts and color pattern, and is slightly
darker above than true _longicauda_. Another subadult male in the white
winter coat from Palo Alto County, no. 35756, Univ. Michigan, has a
large skull, which shows approach to _primulina_ in its narrowness
anteriorly and in some other features. Although the tail is of moderate
length, the body is large as in _spadix_ or _longicauda_, and the
length of the hind foot suggests _spadix_ or _longicauda_.

A subadult male, no. 425a, Iowa State College, from Manson, Iowa, in
brown winter pelage, agrees with _primulina_ in the restriction of the
area of the light color of the underparts and in less expanded
zygomatic arches. The teeth are intermediate in size between those of
_noveboracensis_ and _primulina_ on the one hand and those of _spadix_
and _longicauda_ on the other. In other respects it agrees with, or is
more nearly like, _spadix_.

An adult female, no. 426a, Iowa State College, from Barnum, in the
brown winter coat, agrees with _primulina_ except that the orbitonasal
length of the skull is more as in _spadix_ and the presence of some
light color on the lower part of the hind legs suggests _spadix_. The
skull only, no. 440a, Iowa State College, labeled merely Webster
County, Iowa, is almost a duplicate of no. 426a. A subadult male, no.
427a, Iowa State College, from Moorland, Iowa, only about six miles
southeast of Barnum, likewise is indistinguishable from _primulina_
except for having a white winter coat and in being relatively broad in
the mastoidal region. Nevertheless, both of these animals are here
referred to _spadix_ because the average of specimens from this general
area is nearer that of _spadix_. No. 497a, Iowa State College, an adult
female in white winter pelage, from Ames, approaches _primulina_ in the
narrow rostrum and smaller teeth but otherwise approaches or even
agrees with _spadix_.

Two adult males, without external measurements, from Pilot Mound, Iowa,
have skulls quite like males of _longicauda_ from Alberta. The only
approach noted to eastern forms is the restricted color of the
underparts on no. 2856, Coe College, which has a brown winter coat. The
color of the underparts is not extended so far out on the feet as in
_longicauda_. Also the tympanic bullae of this specimen are a trifle
narrower. The other male, no. 2652, is in the white winter coat. The
one female from the same place, no. 2660, Coe College, in brown winter
pelage, has a skull notably unlike that of _longicauda_ or _spadix_;
the skull is narrower and practically indistinguishable from that of
the largest female skull of _primulina_ available from Lawrence,
Kansas, save that the tooth-row is much longer. The color pattern also
agrees with that of _primulina_ or _noveboracensis_ in that the color
of the underparts extends only as far as the knee on the hind legs and
is narrow on the belly. Nevertheless, another adult female, no. 120a
from Amaqua Township, some 6 miles southwest of Pilot Mound, is in all
respects typical of _spadix_. This is the more remarkable because
another comparable specimen from less than 20 miles to the southwest in
Worth Township is equally typical of _primulina_.

Two young females from Chester, Iowa, nos. 2656 and 2874/2873, Coe
College, have skulls larger than those of corresponding age of
_primulina_ or _noveboracensis_. The color is as in spadix. The color
pattern of the underparts also is as in _spadix_ or _longicauda_ except
that the width of the area of light color on the belly is restricted
somewhat although not so much as in _noveboracensis_ or _primulina_.
Of four males from the same place, also in the collection of Coe
College, no. A2874 is a white skin only and does not provide diagnostic
characters. The three other males, each in summer pelage, are marked
and colored as are the two females from the same place except that male
no. 2861 has the color of the underparts so much attenuated on the hind
legs that it barely, uninterruptedly, extends to the feet. No. 2658 is
young, or perhaps barely subadult. The skull is large and referable to
_spadix_. The two adults, nos. 2861 and 2657, differ cranially from
typical (Elk River, Minn.) _spadix_ only in being slightly narrower
across the mastoids and in having the bullae a little narrower. In
these departures they show some approach to _primulina_ and to
_noveboracensis_. Another male, subadult, no. 2867, Coe College, from
Decorah, which has acquired half of the white winter coat, agrees with
the males from Chester except that the preorbital part of the skull is
shortened much as in some specimens of _primulina_.

From Lansing, in extreme northeastern Iowa, a large subadult male, no.
2864, Coe College, of 453 mm. in total length and half through with
acquiring the white winter coat, agrees with the males previously
described from Chester except in having the palate narrower as in
_noveboracensis_. The adult female available from Lansing, no.
2863/2862, Coe College, in white winter pelage except for the top of
the head, although a large skin, has a skull smaller than that of any
_spadix_ or _longicauda_ and of about the same size as that of no.
3838, Univ. Kansas Mus. Nat. Hist., of _primulina_, from Lawrence,
Kansas, except that the skull of no. 2863/2862 is much narrower across
the mastoids. This specimen, then, shows approach to _noveboracensis_
in narrowness of the mastoidal region, to _primulina_ in other respects
and to _spadix_.

Many of these instructive specimens from Iowa, made available to the
present writer by Mr. W. F. Kubichek, were brought together at the Coe
College Museum by the late B. H. Bailey. Most of them were obtained
from trappers who did not supply the conventional external measurements
taken in the flesh. Even though these are lacking, the specimens
clearly show that actual intergradation occurs where the ranges of _M.
f. longicauda_, _spadix_, _noveboracensis_ and _primulina_ meet.

The dark color of the upper parts, restriction of the color of the
underparts on the ankles with the result that the color reaches the
toes in interrupted fashion, and large skull, of no. 18912 of the
Museum of the University of South Dakota, from Roberts County, South
Dakota, clearly place this specimen with _spadix_, rather than with
_longicauda_. Likewise, male, subadult, no. 11376, Univ. South Dakota,
from Clay County, South Dakota, is referable to _spadix_. Although
without external measurements, the specimen obviously is large. The
patch of summer pelage on its head and neck is darker than the summer
pelage of _longicauda_, and the orbitonasal length is greater than the
length of the tympanic bullae; all these features are characters of
_spadix_. The adult male from Fort Sisseton, South Dakota, no. 188407,
United States National Museum, figured by Merriam (1896, p. 20, figs.
7-9), is almost exactly intermediate between _longicauda_ and _spadix_,
although here referred to the latter.

Five specimens, nos. 147375, 147432, 147762, 148720 and 148721, U. S.
Nat. Mus., including 3 skulls only from Beemer, Cuming County,
Nebraska, are intergrades between _M. f. longicauda_, _M. f. primulina_
and _M. f. spadix_. One skin is in white winter pelage and the other, a
female, is in summer pelage which in coloration and color pattern
agrees with that of _spadix_. External measurements of the male agree
with those of _longicauda_. Measurements of the female agree with those
of _spadix_ except that the tail is shorter as in _primulina_. The
skulls are as long as in _longicauda_ but are more slender than in
either _longicauda_ or _spadix_ although nearer the latter in this
respect. In dorsal aspect, the skulls especially posteriorly to the
orbital region, resemble _primulina_. All points considered, the
animals seem best referred to _spadix_.

Although the degree of development of certain morphological features
has been settled upon as indicative of the race _spadix_, some doubt
remains as to where the western boundary of its range should be shown.
This results from the fact that color has been taken into account as
one diagnostic feature and this feature is lacking in the white winter
specimens which, from the following places, are all that are available:
Kittson County, Minnesota; Moorhead, Minnesota; Casselton and Valley
City in North Dakota; Armour, South Dakota and Clay County, South
Dakota. In summary, more specimens in the summer coat will be required
to establish definitely the boundary between the ranges of _longicauda_
and _spadix_.

Surber (1932:49) has referred to additional specimens of this weasel in
the University of Minnesota Museum as from Winona, Hennepin and Isanti
counties of that state.

At Elk River, Minnesota, B. Bailey (1929:156) found this species to be
about half as abundant as _Mustela cicognanii_ and that it is "more
often found in the open timber and about the dry ridges and fields."
Of seventeen adult or subadult skulls of this race from Minnesota, ten
have obvious marks of infestation of the frontal sinuses. In no skull,
however, has the infestation resulted in so much malformation, as
occurs in _noveboracensis_.

     _Specimens examined._--Total number, 76, arranged alphabetically
     by states and from north to south by counties in each state.

     =Iowa.= _Lyon County_: Granite, 1[65]. _Howard County_: Chester,
     6[12]. _Winneshiek County_: Decorah, 1[12]; 8 mi. NE Ossian,
     1[76]. _Allamakee County_: Lansing, 2[12]. _Clay County_: Island,
     1[76]; Webb, 1[2]. _Palo Alto County_: Ruthven, 1[76]; no locality
     more definite than county, 1[76]. _Calhoun County_: Manson, 1[65].
     _Webster County_: Barnum, 1[65]; Moorland, 1[65]; no locality more
     definite than county, 1[65]. _Boone County_: Pilot Mound, 3[12];
     Amaqua Township, Sec. 19, 1[65]. _Story County_: Ames, 1[65].

     =Minnesota.= _Kittson County_, 1[2]. _Roseau County_: 2-1/2 mi. SW
     Roseau, Jadis Township, 1[14]. _Itasca County_: T. 61N, R. 26W,
     1[104]. _Clay County_: Moorhead, 2[9]. _Atkin County_: Atkin,
     1[50]. _Otter Tail County_: Lake Lizzie, 1[9]; Parkers Prairie,
     1[57]. _Grant County_: 3 mi. NW Barrett, 1[76]. _Benton_ (now
     Mille Lacs?) _County_: Princeton, 1[91]. _Sherburne County_: Elk
     River, 14 (6[59], 4[14], 3[91], 1[74]). _Hennepin County_: Fort
     Snelling, 6 (5[2], 1[91]). _Carver? County_: Chaska, 1[60]. _Lac
     qui Parle County_: Madison, 5 (3[91], 2[1]); no locality more
     definite than county, 2 (1[68], 1[75]). _Yellow Medicine County_:
     Wood Lake, 1[2]. _Blue Earth County_: Rapidan, 1[64]. _County_ in
     question: Moore Lake, 1[91].

     =Nebraska.= _Cuming County_: Beemer, 5[91].

     =North Dakota.= _Cass County_: Fargo, 1[91]; Casselton, 1[91].
     _Dickey County_: Oakes, 1[91].

     =South Dakota.= _Roberts County_, 1[102]. _Marshall County_: Fort
     Sisseton, 1[91]. _Douglas County_: Armour, 1[14]. _Clay County_,
     1[102].


=Mustela frenata longicauda= Bonaparte

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

    _Mustela longicauda_ Bonaparte, Charlesworth's Mag. Nat. Hist.,
      2:38, 1838.

    _Putorius longicauda_, Baird, Mamm. N. Amer., p. 169, 1858; Coues,
      Fur-bearing animals, p. 136, 1877; Bangs, Proc. Biol. Soc.
      Washington, 10:7, figs. 1, 1a of pls. 1, 2 and 3, February 25,
      1896; Merriam, N. Amer. Fauna, 11:19, pl. 3, figs. 3, 3a, 4, 4a,
      pl. 5, figs. 1, 1a, text figs. 7-9, June 30, 1896.

    _Mustela longicauda longicauda_, Bailey, N. Amer. Fauna, 49:166,
      January 8, 1927.

    _Mustela frenata longicauda_, Hall, Carnegie Instit. Washington
      Publ. 473:105, November 20, 1936; Hall, Canadian Field-Nat.,
      52:108, October, 1938.

    _Mustela frenata_, Sowls, Journ. Mamm., 29:126, May 14, 1948.

     _Type._--Possibly not in existence. No. 43.3.3.3 [from Carlton
     House, Saskatchewan] in the British Museum of Natural History has
     been regarded by several zoölogists as the type. It is a subadult
     female, skull and skin, from North America. See the account of _M.
     erminea cicognanii_ for reasons for and reasons against regarding
     this specimen as the holotype.

     No. 43.3.3.3 from the collection of Dr. John Richardson is in the
     white winter coat and now (Sept. 24, 1937) is prepared as a study
     skin. Evidences of its once having been mounted are: holes in the
     soles of the hind feet for supporting-wires, large straight wire
     in the tail, folds in the skin of the now backward-projecting hind
     feet, and unevenness of the skin on the back resulting from
     straightening out the specimen. The tip of the tail and some skin
     from the middle of the belly are missing. Otherwise the skin is
     intact. The skull is that of an animal in its first year, lacks
     the zygomatic arch on each side, but otherwise is complete and
     unbroken. The teeth all are present and entire except that p2 on
     the right side is missing from its alveolus.

     _Range._--Transition and Upper Sonoran life-zones of the Great
     Plains, southward from central Alberta, Saskatchewan and southern
     Manitoba through eastern Montana, the Dakotas and Nebraska into
     southeastern Wyoming, northeastern Colorado and western Kansas.
     See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     primulina_ in near (_h_) Clay Color rather than Brussels Brown of
     upper parts, least width of color of underparts more than 40 per
     cent of greatest width of color of upper parts, color of
     underparts extended onto hind foot rather than stopped short of
     ankle, zygomatic breadth more than 28.8 in adult males and more
     than 24.1 in adult females; from _M. f. spadix_ in lighter color
     being near (_h_) Clay Color, in males by deeper occiput in which
     the depth of the skull, exclusive of the sagittal crest and taken
     at the anterior border of the basioccipital amounts to more than
     59 per cent of the mastoid breadth; from _M. f. oribasus_ in near
     (_h_) Clay Color rather than near (14_n_) Brussels Brown color of
     the upper parts and in males by deeper occiput in which the depth
     of the skull, exclusive of the sagittal crest and taken at the
     anterior border of the basioccipital, amounts to more than 59 per
     cent of the mastoid breadth; from _M. f. alleni_ in larger size,
     adult males having a total length of more than 400 millimeters,
     hind foot more than 45, basilar length more than 43.5, and females
     having a total length of more than 375 and basilar length not less
     than 40.0; from _M. f. nevadensis_ in near (_h_) Clay Color rather
     than near (14_n_ to 1) Brussels Brown of upper parts, basilar
     length more than 40 in females and averaging more than 45 in
     males; from _M. f. neomexicana_ by near (_h_) Clay Color rather
     than Buckthorn Brown color of upper parts, absence of white and
     Argus Brown facial markings, and length of tooth-rows amounting to
     more than 37 per cent of basilar length.

     _Description._--_Size._--Male: Five adults from Alberta yield
     average and extreme measurements as follows: Total length, 438
     (418-473); length of tail, 158 (140-193); length of hind foot, 50
     (46-54). Tail averages 56 per cent as long as head and body.
     Length of hind foot averaging more than basal length.
     Corresponding measurements of five adults and subadults from North
     Dakota are as follows: 465 (445-516); 164 (150-179); 51 (50-54).
     Tail averages 55 per cent as long as head and body.

     Female: Six adults (Alberta, 4; Saskatchewan, 1; Manitoba, 1)
     yield average and extreme measurements as follows: Total length,
     401 (383-425); length of tail, 145 (141-159); length of hind foot,
     43 (41-44). Tail averages 57 per cent as long as head and body.
     Length of hind foot more or less than (approximately equal to)
     basal length.

     The average differences in external measurements of the two sexes
     are: Total length, 37; length of tail, 13; length of hind foot, 7.
     General comparisons indicate that the Alberta-taken males may not
     attain so large a size as those from some other areas. Thus the
     differences in external measurements might be some greater
     elsewhere, say, in North Dakota.

     _Externals._--Longest facial vibrissae black, brown or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles (in summer
     pelage) only slightly greater than shown in figure 20.

     _Color._--Winter pelage all white except tip of tail. Summer
     pelage with upper parts near (_h_) Clay Color or near tone 3 and 4
     of Snuff Brown of Oberthür and Dauthenay, pl. 303. Chin and upper
     lips white. Remainder of underparts ranging from near (_a_) Olive
     Ocher to near (16´) Ochraceous Buff. Upper parts of uniform color
     except for occasional darkening of head in front of ears. Color of
     underparts extends distally on posterior sides of forelegs over
     toes onto antipalmar faces of feet and wrists, on medial sides of
     hind limbs to ankles over antiplantar faces of toes and
     distomedial third of each tarsus, and over proximal fourth to
     third of under side of tail. Least width of color of underparts
     averaging, in a series of 10 males from Alberta, 58 (45-60) per
     cent of greatest width of color of upper parts. Corresponding
     figures for 10 females from the same place are 57 (50-74). Black
     tip of tail in same series of males, most of which are in full
     summer pelage, averaging 43 (35-60) mm. long. Thus, averaging
     shorter than hind foot and 27 per cent of length of
     tail-vertebrae.

     As compared with _M. f. neomexicana_, _longicauda_ lacks the white
     facial markings, black ears, black forehead and nose, but
     otherwise is similarly colored. As compared with _M. f.
     nevadensis_, _M. f. oribasus_ and _M. f. spadix_, each of color
     pattern similar to _longicauda_, selected differences of
     _longicauda_ are its much lighter color, especially of the upper
     parts, with less conspicuous darkening on the nose. From _M. f.
     primulina_, _longicauda_ differs in lighter color of upper parts,
     reddish rather than yellowish underparts, and light rather than
     dark-colored hind feet.

     _Skull and teeth._--Male (based on 5 adults from Alberta): See
     measurements and plates 16-18; weight, 4.7 (4.6-4.9) grams;
     basilar length, 46.0 (44.7-46.8); zygomatic breadth more than
     distance between condylar foramen and M1 or than between anterior
     palatine foramen and anterior margin of tympanic bulla; mastoid
     breadth more than postpalatal length; postorbital breadth less
     than length of upper premolars and more than width of
     basioccipital measured from medial margin of one foramen lacerum
     posterior to its opposite; interorbital breadth greater than
     distance between foramen opticum and anterior margin of tympanic
     bulla; breadth of rostrum more or less (usually less) than length
     of tympanic bulla; least width of palate less than greatest length
     of P4; anterior margin of tympanic bulla as far posterior to
     foramen ovale as width of 3 to 4 (including I3) upper incisors;
     height of tympanic bulla more than distance from its anterior
     margin to foramen ovale; length of tympanic bulla more than length
     of lower molar and premolar tooth-row and longer or shorter than
     rostrum; anterior margin of masseteric fossa below talonid of m1
     or anterior half of m2.

     Female (based on 5 adults: Alberta, 3; N. D., 1; Sask., 1.): See
     measurements and plates 31-33; weight, 3.1 (2.8-3.5) grams;
     basilar length, 42.3 (40.0-43.7); zygomatic breadth more or less
     (approximately equal to) than distance between condylar foramen
     and M1 or that between anterior palatine foramen and anterior
     margin of tympanic bulla; postorbital breadth less than length of
     upper premolars and more or less than width of basioccipital
     measured from medial margin of one foramen lacerum posterior to
     its opposite; least width of palate not more than greatest length
     of P4; tympanic bulla as far posterior to foramen ovale as width
     of 3 to 4 (including I3) upper incisors; height of tympanic bulla
     not less than distance from its anterior margin to foramen ovale;
     length of tympanic bulla more than length of lower molar and
     premolar tooth-rows and longer or shorter than rostrum.

     The skull of the female averages 34 per cent lighter than that of
     the male.

     Comparisons of the skull with those of _M. f. primulina_, _M. f.
     spadix_, _M. f. oribasus_, _M. f. alleni_, _M. f. nevadensis_, and
     _M. f. neomexicana_ are made in accounts of those subspecies.

_Remarks._--Richardson's (1829:47) account on which Bonaparte may be
said to have based his name, records measurements in inches and lines
which I transpose into millimeters as follows: Total length, 440 mm.;
length of head and body, 305; length of tail (vertebrae), 135; length
of tail (including fur), 164 mm. Specimen no. 43.3.3.3 in the British
Museum, which has by some persons been regarded as the type, yields
measurements as follows: Total length, 408 (which allows for 15 mm.
loss of the fleshy part of the end of the tail); length of head and
body, 272; length of tail (vertebrae), 136 (= 121 + 15); length of tail
(including fur), 162 (142 + 20 mm. that appears to have been lost).
Richardson's specimen would appear to have been of unusual proportions
and to have been larger than no. 43.3.3.3. Some reasons for and reasons
against regarding this specimen as the holotype are given in the
account of _M. erminea cicognanii_.

The name _longicauda_ was applied to practically all long-tailed
weasels of the western United States at one time but as one after
another of the geographic variants in the mountainous regions were
designated as separable, the name _longicauda_ came to be restricted to
the light-colored, relatively large, animal of the Great Plains.

The intergradation of _longicauda_ with _spadix_ and _oribasus_ has
been commented on in the discussions of those subspecies. The larger
size and darker color of specimens referred to _longicauda_ from Devils
Lake and Grafton, North Dakota, are features indicative of
intergradation there with _spadix_. Two young females from Waterton
Lake Park, Alberta, by their darker than average color, suggest
intergradation with _oribasus_, as, for that matter, does the specimen
from Waterton Lake [= Chief Mountain Lake, in Montana] itself, which,
however, is even darker than the two specimens taken on the Canadian
side of the line and hence is referred to _oribasus_. An adult female,
no. 175586, U. S. Nat. Mus., from Moose Pass, Alberta, examined after
the above was written, is larger than any other female seen of
_longicauda_ and in this respect may show approach to _oribasus_, which
in the northern part of its range is of large size as judged by males
from the Bowron Lake region.

One male, no. 8564, Nat. Mus. Canada, from Max Lake, Turtle Mountain,
Manitoba, presents puzzling characters. The external measurements of
465, 170, and 57, are in keeping with the great length of the skull
which has a basilar length of 48.8. The tooth-rows are 19.3 in length
and the mastoid breadth, 25.4. The relative narrowness indicated by the
mastoid breadth is maintained throughout the skull. The only other
specimens relating to the Turtle Mountains that have been seen are two
male, skins without measurements or corresponding skulls, nos. 38902
and 38903, Amer. Mus. Nat. Hist., labeled as from either "Stump Lake or
Turtle Mts.," North Dakota. One of these, no. 38902, is much darker
than the other. Possibly it is from the Turtle Mountains and the other,
lighter-colored one, is from Stump Lake. Study of additional specimens
from the Turtle Mountains might show the existence there of a distinct
race.

Four specimens, in the collection of Myron Swenk, from Inland, Clay
County, Nebraska, are instructive as showing how intergradation occurs
between _primulina_ and _longicauda_. A subadult male, no. 10, is
intermediate in external measurements and in color but in each instance
is nearer _primulina_. The same is true of the least width of the color
of the underparts. The color of the underparts extends uninterruptedly
over the hind legs to the toes as in _longicauda_, but is absent from
the underside of the tail as in _primulina_. In the skull, the basilar
length, breadth of bulla, and size of teeth are nearer _longicauda_, as
are also the ratios to the basilar length of the length of tooth-rows,
breadth of the rostrum, length of the tympanic bulla, and depth of the
braincase at the anterior margin of the basioccipital. Ratios to the
basilar length of the interorbital breadth, mastoid breadth, zygomatic
breadth, and depth of the skull at the posterior borders of the upper
molars are nearer to those of _primulina_. The relatively long rostrum,
as represented by the orbitonasal length, is nearest to that of
_spadix_. A young, almost subadult, female, no. 7, agrees with
_primulina_ in color, color pattern, and length of hind foot. The other
external measurements are intermediate, but nearer those of
_primulina_. Size of skull and teeth are as in _longicauda_. Relative
proportions of parts of the skull are not diagnostic in specimens as
young as this female. An adult female, skull only, no. 8, agrees with,
or approaches nearer to, _longicauda_ in size of skull and teeth and in
relative proportion of every part studied. A juvenile, skull only, of
questionable sex, no. 9, provides no diagnostic characters. On the
basis of color, these specimens from Inland are distinctly nearer
_primulina_. On the basis of cranial characters they are distinctly
nearer _longicauda_. External measurements are intermediate and are a
little nearer those of _primulina_. By placing the most weight on the
cranial characters, the animals may be referred to _longicauda_. The
same may be said of 2 skins, one skin with a skull, from Hastings,
Nebraska. In each skin the color-pattern is as in _primulina_; in one
the under side of the tail is nevertheless lighter-colored more as in
_longicauda_ and the skull, adult male 121651 American Museum of
Natural History, approaches nearer to _primulina_ in narrowness but has
the large teeth of _longicauda_.

Intergradation with _neomexicana_ is suggested by one specimen, no.
7936, Univ. Kans., from Thomas County, Kansas, which has well-developed
white facial markings.

The specimen, no. 180, Kansas Agric. College, from Glasco, is mounted,
of large size, in white winter pelage, and lacks external measurements.
On the basis of its obvious large size, and a hind foot measurement of
49 millimeters obtained from the mounted skin, the animal is
provisionally referred to _longicauda_ rather than to _primulina_.

_Putorius culbertsoni_ is a name now credited to Coues (1877:136).
Although Coues probably intended only to indicate that Baird wrote this
name on the labels of two specimens in the mammal collection of the
Smithsonian Institution, Coues gave an "indication" of the application
of the name by publishing at the same time the catalogue numbers of
specimens whose labels bore the name and thus, in accordance with
article 21 of the International Rules of Zoölogical Nomenclature,
himself becomes the author of the name. Of the two specimens mentioned
by Coues, only the first recorded by him, no. 4320 (with skull no.
37995, U. S. Nat. Mus.), can now be found.

Fortunately, the skull of this specimen labeled (see Lyon and Osgood,
1909:218) as taken at Fort Laramie, Wyoming, is well preserved. Its
only defects are a fracture in the left zygomatic arch and the absence
of parts of each of the first lower molars. In deciding on the
subspecific application of the name _Putorius culbertsoni_ Coues, the
skull of the type must be principally relied upon, for there is
available only one other specimen, a skin only (no. 12596, U. S. Nat.
Mus.), from the same place, and it, like the type, is in white winter
pelage and lacks flesh measurements.

The ranges as now known of three subspecies of _Mustela frenata_
approach near to Fort Laramie. These are _M. f. longicauda_, _M. f.
alleni_, and _M. f. nevadensis_. The skull of the type of _culbertsoni_
is not typical of any one of the three mentioned races. The small size
of its teeth and relative (to basilar length) shallowness of the
frontal region of the skull through the postorbital processes of the
frontal are as in _nevadensis_. The zygomatic arches are not so greatly
expanded as in some specimens of _longicauda_ and are more like the
average for _nevadensis_ or _alleni_, as also is the relatively (to
basilar length) long orbitonasal length. However, each of these
characters is subject to variation and alone is not surely diagnostic,
especially toward the margin of the range of any one of the subspecies
concerned. The same may be said of the relatively great breadth of the
skull interorbitally--a feature typically found in _longicauda_. More
important, in my estimation, is the large size of the skull; all parts
measured (excepting the teeth, the depth at the posterior border of the
last upper molars, the zygomatic breadth, and the depth of the tympanic
bullae) equal or approach nearest to the average for males of
_longicauda_ of similar age.

The small size of _alleni_ prevents its identification with
_culbertsoni_. The question of application lies between _nevadensis_
and _longicauda_. If the long-tailed weasel at Fort Laramie is found to
be referable to the race earlier named _longicauda_, no change in
current nomenclature will be effected. If, on the other hand, the
long-tailed weasel from Fort Laramie is found to be referable to
_nevadensis_ this name will have to fall before the earlier proposed
name _culbertsoni_. There is, however, a third possibility, namely,
that the long-tailed weasel of the Transition and Upper Sonoran zones
of southern Wyoming and northern Colorado, as for example, at Lay,
Colorado, may represent a recognizable race characterized by size about
as in _longicauda_, relative proportions of skull about as in
_nevadensis_ and coloration intermediate, to which the name
_culbertsoni_ may apply. For more detailed discussion of this
possibility, see remarks under _M. f. nevadensis_.

Satisfactory application of the name _Putorius culbertsoni_ Coues
requires an adequate series of adult specimens, of both sexes in the
summer coat with external measurements taken in the flesh, from the
type locality and like material from elsewhere in southern Wyoming. On
the evidence furnished by the skull of the type of _culbertsoni_, that
name tentatively is placed in the synonomy of _longicauda_.

Only 2 of 25 adults examined for malformation of the frontal sinuses by
parasites showed evidence of disease.

     _Specimens examined._--Total number, 138, arranged alphabetically
     by provinces and states and further by districts or counties from
     north to south except as otherwise indicated. Unless otherwise
     indicated specimens are in the collection of the United States
     National Museum.

     =Alberta.= St. Albert, 1; S. Edmonton, 3; Islay, 4[77]; Battle
     River, south of Camrose, 1[77]; Daysland, 1[77]; Moose Pass, 1;
     Blindman River, 2 (1[75], 1[2]); Red Deer, 3 (2[2], 1[60]);
     Bearberry Creek near Sundre, 1[77]; Canad. Nat. Park, N.W.
     Territory, 1[60]; Red Deer River, Didsbury, 1; Canmore, 1;
     Calgary, 11 (6[60], 2[1], 1[86]); Red Deer River, 3[2]; Little
     Sandhill Creek, Red Deer River, 1[77]; Waterton Lake Park, 2[77];
     Sweetgrass Hills, 1[77]; Alberta, 1[14].

     =Colorado.= _Yuma County_: Wray 4 (1[88], 3[74]).

     =Kansas.= _Rawlins County_: 7 mi. N, 3 mi. W Beardsley, 1[74]; 6
     mi. S and 2 mi. E Atwood, 1[74]; 15 mi. SE Atwood, 1[74]. _Thomas
     County_: near Brewster, 2[93]; no locality more definite than
     county, 2[93]. _Trego County_, 2 (1[2]). _Cloud County_: Glasco,
     1[67].

     =Manitoba.= Portage la Prairie, 3[75]; Carberry, 2 (1[2], 1[1]);
     Carman, 1[60]; Max Lake, Turtle Mt., 1[77].

     =Montana.= _Glacier County_: St. Marys Lake, 1; Blackfoot, 1:
     Blackfoot Agency, 1. _Blaine County_: 6 mi. east Chinook, 1[74].
     _Pondera County_: 1/2 mi. SE Conrad, 1[74]. _Toole County_: Shelby
     Junction, 1. _Hill County_: Havre, 1. _Fergus County_: Moccasin
     Mts., 5 mi. NW Hilger, 1; 7 mi. NE Hilger, 1. _Rosebud County_:
     3/4 mi. N Ingomar, 1. _County_ in question, Milk River, 2.

     =Nebraska.= _Dawes County_: Chadron, 2[35]. _Cherry County_:
     Kennedy, 1; no locality more definite than county, 1. _Brown
     County_: Long Pine, 1[68]. _Antelope County_: Neligh, 1[35].
     _Adams County_: Hastings, 2[2]. _Clay County_: Inland, 4[35].

     =North Dakota= (arranged by counties from west to east). _Divide
     County_: Crosby, 1. _Mountrail County_: Lostwood, 1. Little
     Missouri River, 1. _Golden Valley County_: Sentinel Butte, 1.
     _Billings County_: Medora, 1[60]. _McLean County_: 3 mi. W
     Elbowoods, 1. _Oliver County_: Ft. Clark, 2. _Morton County_:
     Mandan, 1. _Sioux County_: 3 mi. N Cannonball, 1. _Logan County_:
     6 mi. SW Napoleon, 1. _Rolette County_: Turtle Mts., 1[76]; Fish
     Lake, 1. _Benson County_: Ft. Totten, 3[14]; Sully Hill Nat. Park,
     1. _Ramsey County_: Devils Lake, 2. Stump Lake or Turtle Mts.,
     2[2]. _Nelson County_: Stump Lake, 1. _Grand County_: Larimore, 1.
     _Walsh County_: Grafton, 11 (4[76], 3[74], 2[2]). _Stutsman
     County_: Jamestown, 1. _Barnes County_: Valley City, 1.

     =Saskatchewan.= Wingard, 5; Osier, 2[75]; Simpson, 1[2]; Touchwood
     Hills, 4[7]; South arm Last Mountain Lake, 1[77]; Rush Lake
     (Assiniboia, N.W.T.), 2[75].

     =South Dakota.= _Pennington County_: Rapid City, 1.

     =Wyoming.= _Goshen County_: Fort Laramie, 2.


=Mustela frenata oribasus= (Bangs)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32, 33 and 40

    _Putorius (Arctogale) longicauda oribasus_ Bangs, Proc. New England
      Zoöl. Club, 1:81, December 27, 1899.

    _Putorius longicauda_, Coues, Fur-bearing animals, p. 136, 1877
      (part).

    _Mustela longicauda oribasus_, Miller, U. S. Nat. Mus. Bull.,
      79:98, December 31, 1912.

    _Mustela longicauda oribasa_, Hall, Univ. California Publ. Zoöl.,
      40:368, November 5, 1934.

    _Mustela frenata oribasa_, Hall, Carnegie Instit. Washington Publ.
      437:105, November 20, 1936.

     _Type._--Female, adult, skull and skin; no. 9058, collection of E.
     A. and O. Bangs, but now in collection of Mus. Comp. Zoöl.; source
     of Kettle River, 7500 feet [the summit between middle fork of
     Kettle River and Cherry Creek at Pinnacles--oral information from
     the collector, Feb. 12, 1936], British Columbia; September 10,
     1898; obtained by Allan Brooks; original no. 1368.

     The skull (plate 40) is complete and unbroken. The teeth all are
     present and entire except right I^3 which has the anterior half
     broken away. The skin is complete, fairly well made, and in summer
     pelage.

     _Range._--Canadian and Hudsonian life-zones from near 56°N in the
     Rocky Mountains of British Columbia and Alberta and Ootsa Lake
     along the Fraser and Chilcotin rivers south to Alta Lake, in the
     Caribou and Monashee mountains, probably in the Selkirks and
     Rockies, and through the Rockies of Montana into extreme northern
     Wyoming. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     longicauda_ by near (14 _n_) Brussels Brown rather than near (_h_)
     Clay Color of upper parts and in males by relatively shallower
     occiput in which the depth of the skull, exclusive of the sagittal
     crest and taken at the anterior border of the basioccipital,
     amounts to less than 59 per cent of the mastoid breadth; from _M.
     f. nevadensis_ by greater average size, see measurements.

     _Description._--_Size._--Male: Two adults from Florence, Montana,
     measure as follows: Total length, 440, 440; length of tail, 165,
     161; length of hind foot, 47, 49. Corresponding measurements of an
     adult male from Quesnel, British Columbia, are: 443; 168; 55. Tail
     amounts to 60, 58, and 61 per cent as long as head and body.
     Length of hind foot averages more than basal length.

     Female: The type specimen, the only typical adult or subadult
     specimen of this sex of which external measurements are available,
     measures: Total length, 392, length of tail, 150, length of hind
     foot, 46. Tail is 63 per cent as long as head and body. Length of
     hind foot amounts to more than basal length.

     The differences in external measurements, between the one female
     and the average of the three males are: Total length, 49; length
     of tail, 15; length of hind foot, 4.

     _Externals._--Longest facial vibrissae brown or white (often both
     colors in same specimen) and extending beyond ear; carpal
     vibrissae same color as underparts and extending to or beyond
     apical pad of fifth digit; hairiness of foot-soles (in summer
     pelage) slightly less than shown in figure 19.

     _Color._--Upper parts, in summer, near (14 _n_) Brussels Brown,
     more blackish and less reddish than tone 4 of Burnt Umber of
     Oberthür and Dauthenay, pl. 304; in type near tone 4, pl. 301 of
     Oberthür and Dauthenay. Underparts, in summer, Buff Yellow or near
     (20 _c_) Amber Yellow. In winter, all white except tip of tail
     which is at all times black. Upper parts of uniform color except
     for occasional slight darkening of top of head and along
     mid-dorsal line of back. Color of underparts extends distally on
     posterior sides of forelegs over feet, on medial sides of hind
     limbs over antiplantar faces of toes and over proximal two-thirds
     of ventral side of tail. Least width of color of underparts
     amounting to 43 per cent of greatest width of color of upper
     parts, 75 per cent in male from 4 miles northeast of Quesnel,
     British Columbia, and 52 (33-66) in four males from Montana. Black
     tip of tail in four males from Montana averaging 50 (44-60) mm.
     long. Thus averaging approximately as long as hind foot and 33 per
     cent of length of tail-vertebrae.

     Color not different than in many specimens of _M. f. nevadensis_.
     Color comparison with _M. f. longicauda_ has been made in the
     account of that subspecies.

     _Skull and teeth._--Male (based on 5 adults and 2 subadults from
     British Columbia and 4 adults from Montana): See measurements and
     plates 16-18. As described in _Mustela frenata longicauda_ except
     that: Weight, 5.0 (3.8-6.0) grams; basilar length, 46.7
     (43.6-48.8); postorbital breadth in one of nine instances less
     than width of basioccipital measured from medial margin of one
     foramen lacerum posterior to its opposite; interorbital breadth
     more or less than distance between foramen opticum and anterior
     margin of tympanic bulla; breadth of rostrum less than length of
     tympanic bulla; anterior margin of tympanic bulla as far posterior
     to foramen ovale as width of 2-1/2 to 5 upper incisors; length of
     tympanic bulla not less than length of lower molar and premolar
     tooth-row and shorter than rostrum.

     Female (based on the type, specimen): See measurements and plates
     31-33, 40. As described in _Mustela frenata longicauda_ except
     that: Weight, 3.5 grams; basilar length, 41.6 mm.; zygomatic
     breadth more than distance between anterior palatine foramen and
     anterior margin of tympanic bulla; postorbital breadth more than
     width of basioccipital measured from medial margin of one foramen
     lacerum posterior to its opposite; least width of palate more than
     outside length of P^{4}; tympanic bulla as far posterior to
     foramen ovale as width of 4-1/2 upper incisors; height of tympanic
     bulla less than distance from anterior margin of tympanic bulla to
     foramen ovale; length of tympanic bulla less than length of
     rostrum. If more than one skull were available of the female of
     _oribasus_ it is believed that the description would agree with
     that of _longicauda_ in nearly all features.

     The skull of the female is 30 per cent lighter than that of the
     average male.

Comparison with _longicauda_ reveals that, on the average, skulls of
males are larger, relative to the basilar length broader across the
mastoids, shallower through the braincase as measured at the anterior
end of the basioccipital exclusive of the sagittal crest, with longer
rostrum. Compared with _nevadensis_, the skull averages larger in all
measurements taken, and has a relatively broader rostrum, relatively
greater mastoid breadth and a braincase which is shallower relative to
the basilar length. By weight, the skull of _nevadensis_ is a fourth
lighter, and in linear measurements 5 to 18 per cent smaller.

_Remarks._--Some of the specimens from Montana, which here are referred
to _oribasus_, more than half a century ago were listed by Coues
(1877:138) under the name _longicauda_. It was not until 1899 that this
race was given a name by Bangs, who at that time (1899B:81) accurately
made out the distinctive color features. Distinctive cranial characters
cannot be described with assurance even now because there still are too
few specimens.

The type specimen, at one time examined by the present writer, has on
the stuffed skin no well-developed mammae, scrotal pouch, or other
visible sexual part. Probably the collector's sex mark for female is
correct.

As judged by the two skulls of subadult males from the Barkerville
region, individuals of this race attain larger size than do those of
_longicauda_. On the basis of larger size than either _longicauda_ or
_nevadensis_, the specimens from the Rocky Mountains of Montana and two
from northern Wyoming are referred to this race. The short, wide, flat,
tympanic bullae, relatively great mastoidal breadth, and some other
features of the specimen from Donovan, Montana, point toward
_oribasus_, whereas nearly as many more cranial features, in this
instance mainly differences in size, are indicative of _nevadensis_ to
which race the specimen might almost equally well be referred. Another
male from Darby, in the Bitterroot Valley of Montana, has a slightly
longer hind foot than those from Florence, but a female from Hamilton,
agrees more nearly with _nevadensis_. The average of all the specimens
from the Bitterroot Valley is a little nearer _oribasus_. Four skulls
from Buffalo, Wyoming, here referred to _nevadensis_ show approach to
_oribasus_ in size of skull. The specimens from Big Snowy Mountains,
and the Highwood Mountains of Montana are too young clearly to show
size of the adult skull, but are distinctly darker colored than
_longicauda_ of the plains country proper. Of two subadult females from
Tacy, Montana, the color of the one in summer pelage is distinctly
nearer that of _oribasus_ and _nevadensis_ than it is to that of
_longicauda_ to which some approach in color might be expected. The
reduced size of both of the specimens is further suggestive of
_nevadensis_ and it may be that adult specimens from these more eastern
mountainous areas in Montana will show that _nevadensis_ is the name
proper to apply to animals of this region.

Intergradation with _nevadensis_ is suggested by specimens collected
from along the upper reaches of Okanagan Lake, British Columbia, by
Major Allan Brooks and Mr. J. A. Munro and by a series of skulls from
Ione, Pend Orielle County, Washington, lent me by Mr. Walter Dalquest.
At each place, the average of all specimens is nearest to that of
_nevadensis_.

Specimens from near Waterton Lake show several steps in the transition
from the light-colored _longicauda_ type of coloration to the darker
coloration characterizing _oribasus_. One taken here, at a time when
the body of water referred to seems to have been known as Chief
Mountain Lake, is barely dark enough to be placed with _oribasus_. Two
other specimens from across the Canadian Border labeled as "Waterton
Lake Park" are slightly lighter colored above, and on this account are
placed with _longicauda_.

The two adult males from Lillooet, British Columbia, are referable to
_oribasus_ although neither is quite typical. One has a saturated
coloration suggestive of that of _altifrontalis_ and the skull is
shorter and broader than in other specimens of _oribasus_. The female
from Lillooet, skin alone, no. 916, Prov. Mus., B. C. is small for
_oribasus_. The female, no. 1539, collection of Kenneth Racey, from
Alta Lake, in brown winter pelage, in almost every measurement falls
nearly midway between _altifrontalis_ and _oribasus_ but slightly
nearer the latter. The skull from Chezacut and 3 animals from Wistaria,
British Columbia, probably are females and show a greater average size
than specimens from farther to the southeast. For example, the basilar
length of the skull, 44.8 (44.3 to 45.1), exceeds that of the type
specimen. The animals from Wistaria on Ootsa Lake furnish the
northwesternmost station of occurrence of which I have record for this
subspecies.

The northernmost records of occurrence, at "Clearwater River, Peace
River, B. C," and at Little Prairie, are furnished by a white skin
without skull, no. 257450, U. S. Nat. Mus., purchased on August 2,
1932, at the place mentioned by W. H. Sheldon and Richard Borden, and a
skull with white winter skin, no. 3585, Provincial Museum, British
Columbia, respectively. The characters distinguishing _longicauda_ and
_oribasus_ are not shown by white winter skins; the skull shows some
features of _longicauda_, and the reference of these specimens to
_oribasus_ rather than _longicauda_ is tentative.

Only the skull from Little Prairie shows evidence of infestation of the
frontal sinuses by parasites. In the Barkerville area of British
Columbia, Mr. and Mrs. Thomas T. McCabe obtained only 2 skulls of this
subspecies from a total of 238 weasel skulls gathered by local
trappers. The others were _Mustela erminea_.

     _Specimens examined._--Total number, 46, listed by localities from
     north to south and unless otherwise indicated, in the United
     States National Museum.

     =British Columbia.= West of Hudson Hope, 1[7]; Clearwater River,
     tributary to Peace River, 1; Little Prairie, a few miles south of
     Peace River and about 40 miles west of the main highway between
     Dawson Creek and Fort St. John, 1[85]; Wistaria, 3[85]; Four Mile
     Creek, 4 mi. NE Quesnel, 1[21]; Isaacs Lake, 3200 ft., 1[74];
     Barkerville region, 1[74]; Clear River, 4800 ft., 1[74]; Chezacut,
     1[31]; Lillooet 3 (2[77], 1[85]); Alta Lake, 1[31]; source of
     Kettle River, 7500 ft., 1[75]; E side Beaverfoot Range, 4000 to
     4500 ft. between Fraser Creek and 6 mi. SE of Fraser Creek, 1[74];
     Cranbrook, 1[86]; head of Cross River, 10 mi. below Assiniboine
     Pass, 1[7]; camp east of "Kootanie," 1[7]; camp east of Kootanie
     River, 1[7].

     =Alberta.= Thoral Creek, 7000 ft., 50 mi. NE Jasper, 1[2].

     =Montana.= _Glacier? County_: Chief Mt. Lake (= Waterton Lake), 1.
     _Flathead County_: Columbia Falls, 1. _Chouteau? County_: Highwood
     Mts., 1. _Fergus? County_: Big Snowy Mts., 1. _Wheatland County_:
     Harlowton, 1[74]. _Ravalli County_: Florence, 2; Hamilton, 1[56];
     Darby, 1[56]; Carlos [= Charlos] Heights, 2[74]; Tin Cup District,
     2[74]; no locality more definite than county, 2[74]. _Beaverhead
     County_: Donovan, 1. _Madison County_: Sheridan, 1[74]. _Gallatin
     County_: Ranch 7-11, Eldridge, 1[60]. _Stillwater County_: Tacy,
     2[76]. _County_ in question: Gallatin Valley, 1; Yellowstone Park,
     1[75].

     =Wyoming.= Glen Creek, Mammoth Hot Springs, 1. _Park County_: Four
     Bears, 1[2].


=Mustela frenata alleni= (Merriam)

Long-tailed Weasel

Plates 18, 19, 20, 31, 32 and 33

    _Putorius alleni_ Merriam, N. Amer. Fauna, 11:24, June 30, 1896.

    _Mustela alleni_, Miller, U. S. Nat. Mus. Bull., 79:99, December
      31, 1912.

    _Mustela frenata alleni_, Hall, Carnegie Instit. Washington Publ.
      473:106, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 186451, U. S. Nat. Mus.
     (formerly 4485/5120, collection of Dr. C. Hart Merriam); Custer,
     South Dakota; obtained by Vernon Bailey; original no. 90.

     The skull is complete and unbroken. The upper incisors are
     missing. All the other teeth are present although the premolars,
     and especially the canines, are much worn, possibly as the result
     of the animal's efforts to free itself from a trap. The skin is
     fairly well made, in a good state of preservation, and entire.

     _Range._--Canadian, Transition and Upper Sonoran life-zones of the
     Black Hills of South Dakota and adjacent semi-bad-land territory
     of Wyoming and Nebraska southward to Mitchell, Scottsbluff County.
     See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     longicauda_ in smaller size, adult males having a total length of
     less than 400, hind foot less than 45, basilar length less than
     43.5, and in adult females total length less than 375, and basilar
     length less than 40; from _M. f. nevadensis_ in near Clay Color
     rather than near (14 _n_ to _l_) Brussels Brown of upper parts in
     summer.

     _Description._--_Size._--Male: External measurements of the type
     specimen are: Total length, 372; length of tail, 137; length of
     hind foot, 44. Tail is 58 per cent as long as head and body.
     Length of hind foot more than basal length.

     Female: No external measurements for typical adults are available.
     No. M1 #41 from Mitchell, Scottsbluff Co., Nebraska, an adult
     female which is an intergrade with the larger _M. f. longicauda_,
     measures as follows: Total length, 367; length of tail, 120;
     length of hind foot, 41.

     _Externals._--Longest facial vibrissae dark brown or white and
     extending beyond ear; carpal vibrissae same color as underparts
     and extending to apical pad of fifth digit; hairiness of
     foot-soles (in summer pelage) as shown in figure 20.

     _Color._--Winter pelage unknown; probably white except, of course,
     tip of tail. Summer pelage as described in _Mustela frenata
     longicauda_ except that: Least width of color of underparts
     averaging, in 3 males from Black Hills, 54 (38-62) per cent of
     greatest width of color of upper parts. Black tip of tail
     averaging 43 (40-45) mm. long. Thus, averaging approximately same
     length as hind foot and in type specimen amounting to 33 per cent
     of length of tail-vertebrae.

     _Skull and teeth._--Male (based on the type and no. 7440 Amer.
     Mus. Nat. Hist., from Hill City, S. Dak.): See measurements and
     plates 18-20. As described in _Mustela frenata longicauda_ except
     that: Weight, 3.1 (3.0-3.2) grams; basilar length, 41.0
     (40.9-41.0); mastoid breadth not less than postpalatal length;
     breadth of rostrum more than length of P4; anterior margin of
     tympanic bulla as far posterior to foramen ovale as width of 4 to
     5 upper incisors; height of tympanic bulla more or less than
     distance from its anterior margin to foramen ovale.

     Female (based on no. 7441, American Mus. Nat. Hist., from Black
     Hills, S. Dak.): See measurements and plates 31-33. As described
     in _Mustela frenata longicauda_ except that: Weight, 2.0 grams;
     basilar length 37.6. The skull of the female is 35 per cent
     lighter than the average for the two males.

     Comparison with _M. f. longicauda_ and _M. f. nevadensis_ reveals
     that the tympanic bullae average more nearly flat and that the
     skull is smaller.

_Remarks._--Animals of this subspecies were described and named by
Merriam in 1896 as a distinct species on the basis of two or possibly
three specimens from the Black Hills of South Dakota and the name seems
never to have been applied to specimens from other regions. Vernon
Bailey obtained only the one specimen, the type, on his trip in 1888,
but two more were obtained for the American Museum of Natural History
by Walter Granger in 1894.

_Mustela frenata alleni_ combines the light coloration of _M. f.
longicauda_ with the small size of _M. f. nevadensis_. Indeed, the size
may average less than that of _nevadensis_. _M. f. alleni_ seems to
reach its extreme of small size in the Black Hills of South Dakota.
Specimens from Mitchell, Scottsbluff County, Nebraska, here referred
to alleni are of larger size and in this respect are intermediate
between the subspecies _alleni_ and _longicauda_. Of the two specimens
available from Chadron, Nebraska, and here referred to as _longicauda_,
the female, M1 #6, is almost exactly intermediate in size between
_alleni_ and _longicauda_, whereas the male, Ml #11, is as large as the
average-sized _longicauda_.

None of the nine skulls (5 adults) shows malformation resulting from
the infestation of the frontal sinuses with parasites.

     _Specimens examined._--Total number, 10, as follows.

     =Wyoming.= _Crook County_: Sundance, 1[91].

     =South Dakota.= _Pennington County_: Hill City, 1[2]; 20 mi. N Elk
     Mt, 1[91]. _County_ in question: Black Hills, 1[2]. _Custer
     County_: Custer, 2 (1[91], 1[2]).

     =Nebraska.= _Scottsbluff County_: Mitchell, 4[35].


=Mustela frenata arizonensis= (Mearns)

Long-tailed Weasel

Plates 19, 20, 21, 31, 32 and 33

    _Putorius arizonensis_ Mearns, Bull. Amer. Mus. Nat. Hist., 3:234,
      June, 1891; Merriam, N. Amer. Fauna, 11:22, fig. 12, June 30,
      1896.

    _Mustela arizonensis_, Miller, U. S. Nat. Mus. Bull., 79:99,
      December 31, 1912.

    _Mustela frenata arizonensis_, Hall, Carnegie Instit. Washington
      Publ. 473:106, November 20, 1936.

     _Type._--Female, adult, skull and skin; no. 2490/1886, Amer. Mus.
     Nat. Hist.; San Francisco Forest [then (1886?), Yavapai County],
     Arizona; June 20, 1886; obtained by Edgar A. Mearns.

     The skull (plates 31-33) is complete and unbroken save for a small
     puncture in the right squamosal. The incisors above and below and
     M^2 and P^2 on each side are missing. Four canines are preserved
     separately. Otherwise the teeth are in place. The skin has been
     taken down from a mount. Some hair has been lost from in front of
     the ears. Seven mammae are evident and show the animal to have
     been nursing young. The slightly faded color was mentioned by
     Mearns in the original description. He says (1891:234): "The
     memorandum of the colors was made before skinning, the specimen
     having been subsequently preserved in a solution of alum and salt,
     which extracted much of the coloring matter."

     _Range._--Transition to Hudsonian life-zones of Arizona and
     extreme western New Mexico, along the Colorado River, and south of
     the Little Colorado River, from San Francisco Mountain region
     along Mogollon Plateau to extreme western New Mexico. See figure
     29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     neomexicana_ by near (14 _n_) Brussels Brown rather than Buckthorn
     Brown color of upper parts, in absence rather than presence of
     white frontal spot continuous with color of underparts, in basilar
     length of less than 44 in males and 39.3 in females; from _M. f.
     nevadensis_ in that total length averages less than 375 in males
     and 330 in females, basilar length averaging less than 41 in males
     and less than 36.7 in females.

     _Description._--_Size._--Male: No. 24679/32071, from
     Springerville, and no. 248993 from the Kaibab Plateau, measure
     respectively, as follows: Total length, 363, 367; length of tail,
     140, 143; length of hind foot, 41.5, 41.0. Tail is 63, and 64 per
     cent as long as head and body. These males, the only specimens of
     that sex of which external measurements are available, probably
     are grading toward _nevadensis_ and therefore are nontypical.

     Female: Three specimens, one young from Little Spring, a subadult
     from Deadmans Flat and the type specimen, measure respectively as
     follows: Total length, 323, 296, 302; length of tail, 110, 101,
     109; length of hind foot, 38, 33, 36. These average, 307, 107, 36.
     Tail averages 53 per cent as long as head and body.

     Differences in external measurements of the two sexes are: Total
     length, 56; length of tail, 39; hind foot, 5.5.

     _Externals._--Longest facial vibrissae black, brown or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot soles (in summer
     pelage) about as shown in figure 19.

     _Color._--Winter pelage unknown. Summer pelage with upper parts
     near (14 n) Brussels Brown or tone 2 of Raw Umber of Oberthür and
     Dauthenay, Pl. 301, darker on top of head from nose to line
     connecting posterior margins of ears. Tip of tail always black.
     Chin and upper lips white. Remainder of underparts Buff Yellow to
     Straw Yellow and rarely Ochraceous Buff. Color of underparts
     extends distally on posterior sides of forelegs over toes onto
     antipalmar faces of feet and wrists, on medial sides of hind legs
     to ankles and over antiplantar faces of toes, medial third of
     tarsus, and over proximal fifth to fourth of ventral side of tail.
     Least width of color of underparts averaging, in 8 specimens, 44
     (29-54) per cent of greatest width of color of upper parts. Black
     tip of tail, in four females averaging 35 (33-38) mm. long. Thus,
     averaging shorter than hind foot and 32 per cent of length of
     tail-vertebrae. Three of the eight specimens before me (no. 242671
     from 25 mi. SE Flagstaff, not available at time of this
     accounting) have the dark spot near the angle of the mouth faintly
     indicated, whereas the other five lack the spots. The color is as
     in _M. f. nevadensis_.

     _Skull and teeth._--Male (based on 55211, 65231, and 248993; see
     p. 422): See measurements and plates 19-21; weight 2.7 and 3.1
     grams; basilar length, 40.4; zygomatic breadth more than distance
     between condylar foramen and Ml or than between anterior palatine
     foramen and anterior margin of tympanic bulla; mastoid breadth
     more than postpalatal length; postorbital breadth less than length
     of upper premolars and more than width of basioccipital measured
     from medial margin of one foramen lacerum posterior to its
     opposite; interorbital breadth more or less than distance between
     foramen opticum and anterior margin of tympanic bulla; breadth of
     rostrum less than length of tympanic bulla; least width of palate
     more or less than medial length of P4; anterior margin of tympanic
     bulla as far posterior to foramen ovale as width of 3-1/2
     (including I3) upper incisors; height of tympanic bulla more than
     distance from its anterior margin to foramen ovale; length of
     tympanic bulla more than length of lower molar-premolar tooth-row
     and longer or shorter than rostrum; anterior margin of masseteric
     fossa below talonid of m1.

     Female (based on the type specimen): See measurements and plates
     31-33; weight, 1.6 grams; basilar length, 35.5; zygomatic breadth
     less than distance between condylar foramen and M1 and more than
     distance between anterior palatine foramen and anterior margin of
     tympanic bulla (nearly equal in each instance); postorbital
     breadth less than length of upper premolars and greater (7.1-8.4)
     than width of basioccipital measured from medial margin of one
     foramen lacerum posterior to its opposite; least width of palate
     equal to inside length of P4; tympanic bulla as far posterior to
     foramen ovale as width of 3 (including I3) upper incisors; height
     of tympanic bulla more than distance from its anterior margin to
     foramen ovale; length of tympanic bulla more than length of lower
     molar-premolar tooth-row and greater than length of rostrum.

     The skull of the female averages 41 per cent lighter than that of
     the male.

Compared with the skull of _M. f. nevadensis_, that of _arizonensis_ is
smaller, less heavily ridged and has more inflated tympanic bullae and
a relatively greater mastoid breadth. Comparison with the skull of _M.
f. neomexicana_ is made in the account of that subspecies.

_Remarks._--In 1891 Mearns (234-235) named this weasel as a full
species on the basis of two individuals taken by him in 1886 and 1887.
Since that time only a few additional specimens have been preserved.
Only four are adults. Although this material does not permit of a
definition of the subspecies as precise as could be wished, still, it
clearly shows that the animals from the plateau region of Arizona are
recognizably different from those farther north in the Sierra Nevada of
California and those of the Rocky Mountains and Great Basin region
northward to the Canadian border. These more northern animals have gone
by Mearns' name, _arizonensis_, since the date of its proposal until
1939 when the name _nevadensis_ was proposed.

The smaller size, especially of the skull, and the greater inflation of
the tympanic bullae are the outstanding characters which distinguish
_arizonensis_ from the similarly marked _nevadensis_. The bullae are
relatively much inflated throughout but especially so on the
posteromedial parts.

Although the three adult males and two subadult females available of
this subspecies are smaller in most parts measured than any of the
scores of _nevadensis_ of similar age that have been measured, overlap
in size probably will be found as additional specimens of _arizonensis_
become available. A young female, no. 18513, coll. D. R. Dickey, from
Little Spring, does have certain cranial measurements as large as are
found in the minimum-sized _nevadensis_ from farther north.

Intergradation with the two subspecies whose geographic ranges adjoin
that of _arizonensis_ is indicated by specimens at hand. One of these
is the adult male from 25 miles southeast of Flagstaff, which shows
decided approach to _neomexicana_, in color and in possessing white
facial markings less well developed than in _neomexicana_. Even better
developed white facial markings, with intervening blackish coloration,
are displayed by no. 148271, U. S. Nat. Mus., from 8500 feet altitude
on Willow Creek, New Mexico. This subadult female shows approach to
_neomexicana_ also in larger size of the skull and entire animal. The
great inflation of the posterior part of each of its bullae and the
dark color of the upper parts are characters of _arizonensis_. The
color of the underparts stops at the ankles leaving the hind feet dark
colored, in which respect the specimen is unlike either _neomexicana_
or _arizonensis_. If additional specimens showing the same characters
as this one be found at other nearby localities they probably should be
given recognition as a separate subspecies. For the present it seems
best to regard the specimen merely as an intergrade. Although it might,
with almost equal propriety, be referred to either _neomexicana_ or
_arizonensis_, the specimen is here placed with the latter. The
subadult male from Springerville, Arizona, is of larger size than the
topotypical male of _arizonensis_ and in this respect shows slight
approach to _nevadensis_. The narrower mastoidal breadth and slightly
less inflated tympanic bullae of the male from the Kaibab Plateau may
reflect merely individual variation or may represent intergradation in
these features with _nevadensis_.

The statement made by Merriam (1896:22) that, "The type specimen . . .
is an immature female and is of unusually small size. A male obtained
by him [Mearns] near the same place is of the normal size, as is
another male in the Department collection from Springerville, Ariz.,
collected by E. W. Nelson," needs correction. The female is not
immature. The specimen obtained by Mearns near the same place probably
refers to Amer. Mus. No. 2489, from Quaking Asp Settlement, which lacks
both the skull and external measurements. As stuffed it is of small
size for a male. The male from Springerville, as shown by the external
and cranial measurements, is not of normal (_i. e._ average) size, but
is smaller than the average for the other populations of similarly
colored weasels referred to by Merriam (_op. cit._) as _arizonensis_
but here described under the name _nevadensis_.

None of the skulls shows signs of infestation of the frontal sinuses by
parasites.

     _Specimens examined._--Total number, 17, arranged alphabetically
     by states and from north to south by counties in each state.
     Unless otherwise indicated specimens are in the collection of the
     United States National Museum.

     =Arizona.= _Coconino County_: VT Park, Kaibab Plateau, 1; Deadman
     Flat, 6400 ft., 1[74]; Little Spring, 1[59]; Government Prairie,
     near Parks, 1[74]; _Coconino? County_: San Francisco Forest
     (Yavapai Co., in 1886), 1[2]; 25 mi. SE Flagstaff, 1; Quaking Asp
     Settlement, 1[2]. _Apache County_: Springerville, 1; North Fork
     White River, White Mts., 8200 ft., 4[87]; head San Francisco
     River, Judd Ranch, Alpine, 1[74]; 2 mi. SE Big Lake Knoll, 8700
     ft., 24 mi. S Springerville, 1[74]. _Greenlee County_: S end Blue
     Range, 9000 ft., Prieto Plateau, 1; Beaver Creek, 7000 ft., 1[74].

     =New Mexico.= _Grant County_: Mogollon Mts., Willow Creek, 8500
     ft., 1.


=Mustela frenata nevadensis= Hall

Long-tailed Weasel

Plates 19, 20, 21, 33, 34, 35 and 39

    _Mustela frenata nevadensis_ Hall, Carnegie Instit. Washington
      Publ. 473:91, November 20, 1936.

    _Putorius longicauda_, Coues, Fur-bearing animals, p. 136, 1877
      (part); Merriam, N. Amer. Fauna, 5:83, July 30, 1891.

    _Putorius (Gale) brasiliensis frenatus_, Coues, Fur-bearing
      animals, p. 142, 1877 (part).

    _Putorius arizonensis_, Merriam, N. Amer. Fauna, 11:22, figs. 13,
      14, June 30, 1896 (part); Stephens, Mammals of California, p.
      247, 1906.

    _Mustela arizonensis_, Grinnell and Swarth, Univ. California Publ.
      Zoöl., 10:376, October 31, 1913; Whitlow and Hall, Univ.
      California Publ. Zoöl., 40:247, September 30, 1933.

    _Mustela arizonensis arizonensis_, Grinnell, Univ. California Publ.
      Zoöl., 40:102, September 26, 1933.

    _Mustela frenata_, Boyer, Journ. Mamm., 24:99, February 20, 1943.

     _Type._--Female, adult, skull and skin; no. 41053, Mus. Vert.
     Zoöl.; three miles east Baker, White Pine County, Nevada; May 30,
     1929; obtained by E. R. Hall and W. C. Russell; original no. 2674,
     E. R. H.

     The skull (plates 33-35) is complete and unbroken. The teeth all
     are present and entire. The skin is fairly well made. Eight mammae
     are evident and show the animal to have been nursing young.

     _Range._--Altitudinally, 700 feet at Wenatchee, Washington, to the
     highest parts of the mountains of the western United States; Upper
     Sonoran Life-zone to Arctic Alpine Life-zone; southern British
     Columbia in the Cascades and territory west to Monashee Mountains,
     and Nelson, southward in the Cascades of northern Washington, over
     western Washington, Idaho, Utah, and Nevada to northeastern
     Arizona and northern New Mexico; westward from the eastern base of
     the Rocky Mountains in Colorado to the western base of the Sierra
     Nevada and Cascades of California and to the Cascades of southern
     Oregon. See figures 29 and 30 on pages 221 and 314.

     _Characters for ready recognition._--Differs from _M. f. oribasus_
     by smaller average size, see measurements; from _M. f. longicauda_
     by near (14 _n_ to _l_) Brussels Brown rather than near (_h_) Clay
     Color of the upper parts, and in males by a shallower occiput in
     which the depth of the skull, exclusive of the sagittal crest, and
     taken at the anterior border of the basioccipital, amounts to
     less than 59 per cent of the mastoid breadth; from _M. f. alleni_
     by near (14 _n_ to _l_) Brussels Brown rather than near (_h_) Clay
     Color of upper parts in summer; from _M. f. neomexicana_ by near
     (14 _n_ to _l_) Brussels Brown rather than Buckthorn Brown color
     of upper parts, in absence of white frontal spot continuous with
     color of underparts, in basilar length of less than 46 in males
     and 40 in females; from _M. f. arizonensis_ by total length
     averaging more than 375 in males and 330 in females, basilar
     length averaging more than 41 in males and 36.7 in females; from
     _M. f. inyoensis_ by absence of white facial markings; from _M. f.
     pulchra_ by absence of light facial markings, near (14 _n_ to _l_)
     Brussels Brown rather than near (16 _j_) Buckthorn Brown color of
     upper parts, and lesser size, hind foot less than 40 in females
     and basilar length averaging less than 46.0 in males; from _M. f.
     xanthogenys_ by absence of light facial markings and near (14 _n_
     to _l_) Brussels Brown rather than Buckthorn Brown color of upper
     parts; from _M. f. munda_ by absence of white facial markings,
     presence of color of underparts on ventral face of proximal third
     of tail, and hind foot of less than 50 in males; from _M. f.
     saturata_ by presence of light color of underparts on tail and
     ankle and in lesser average breadth across mastoid processes of
     skull (see measurements); from _M. f. oregonensis_ by absence of
     nasofrontal white patch, presence of light color of underparts on
     ventral face of tail, and shorter skull, which, relative to its
     length in males, is deeper through the braincase; from _M. f.
     washingtoni_ by presence of light color of underparts on ventral
     face of tail, by skull which in male relative to basilar length is
     shorter in the preorbital region and wider across the zygomata and
     mastoid processes, and in female has longer preorbital region and
     larger bullae (see measurements); from _M. f. altifrontalis_ by
     lighter colored upper parts which are tones 1 to 3 of Raw Umber,
     pl. 301, rather than tone 4 of Brownish Drab, pl. 302, of Oberthür
     and Dauthenay, by Buff-Yellow to Straw Yellow rather than near
     (14´ _a_ to 16´ _c_) Ochraceous-Buff color of underparts, by least
     width of color of underparts amounting to more than 37 per cent of
     greatest width of color of upper parts, by presence of color of
     underparts on ventral side of tail and on hind leg over ankle, and
     by lesser depth of skull through frontal region; from _M. f.
     effera_ by larger size, males averaging 12-1/2 per cent larger in
     external measurements, 8 per cent larger in linear measurements of
     skull, and 22 per cent heavier in weight of skull, total length
     averaging 400 rather than 360, basilar length averaging 43.6
     rather than 40.5.

     _Description._--_Size._--Male: Twenty-one adults from the southern
     half of the Sierra Nevada of California yield average and extreme
     measurements as follows: Total length, 400 (356-428); length of
     tail, 150 (125-178); length of hind foot, 46.1 (42-50). Tail
     averages 60 per cent as long as head and body. Length of hind foot
     averaging more than basal length. Corresponding measurements of
     twelve adults from extreme southern and southwestern Colorado are
     as follows: 407 (355-431); 150 (133-170); 46.0 (42-49).

     Female: Ten adults from the Sierra Nevada of California yield
     average and extreme measurements as follows: Total length, 349
     (336-362); length of tail, 127 (120-133); length of hind foot,
     36.3 (32-39). Tail averages 57 per cent as long as head and body.
     Length of hind foot less than basal length. Corresponding
     measurements of ten adults from the Rocky Mountains of central
     Colorado are as follows: 347 (325-375); 123 (111-141); 40
     (32-43).

     The average differences in external measurements of the two sexes,
     in the Sierras of California are: Total length, 51; length of
     tail, 23; length of hind foot, 9.8. Weight of 7 adult males from
     California is 267 (226-345) grams. Two adult females from there
     weigh 148 and 115 grams and 3 from White Pine County, Nevada, 134,
     122 and 124, giving an average of 129 grams.

     _Externals._--Longest facial vibrissae black, brown or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles (in summer
     pelage) about as shown in figure 19.

     _Color._--Upper parts, in summer, near (14 _n_ to _l_) Brussels
     Brown or tones 1 to 3 of Raw Umber of Oberthür and Dauthenay, pl.
     301, darker on top of head from nose to line connecting posterior
     margins of ears. Chin and upper lips white. Remainder of
     underparts Buff-Yellow to Straw Yellow and sometimes
     Ochraceous-Buff especially in young, and in some adults from
     southern Colorado. In winter, all white, except tip of tail, or
     upper parts near (_j_) Snuff Brown or lighter than Brussels Brown
     with a smoked effect, and underparts white. Tip of tail at all
     times black. Color of underparts extends distally on posterior
     sides of forelegs over toes onto antipalmar faces of feet and
     wrists, on medial sides of hind legs to ankles, over antiplantar
     faces of toes, medial third of tarsus and usually over proximal
     tenth to three-fourths of ventral side of tail. Least width of
     color of underparts averaging, in a series of twenty males from
     the southern half of the Sierra Nevada of California, 59 (37-76)
     per cent of greatest width of color of upper parts. In seven males
     from southern Colorado corresponding percentages are 55 (37-71).
     Black tip of tail in series from Sierra Nevada averaging 50
     (40-60) mm. long; thus longer than hind foot and averaging 33-1/3
     per cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on 25 adults, from Sierra Nevada
     of California): See measurements and plates 19-21; weight, 3.7
     (2.9-4.9) grams; basilar length, 43.6 (40.6-46.1); zygomatic
     breadth more than distance between condylar foramen and M1 (save
     in four instances) and more than distance between anterior
     palatine foramen and anterior margin of tympanic bulla (save in
     two specimens); mastoid breadth more (80 per cent of specimens) or
     less (20 per cent) than postpalatal length; postorbital breadth
     less than length of upper premolars and more or less than width of
     basioccipital measured from medial margin of one foramen lacerum
     posterior to its opposite; interorbital breadth more or less than
     distance between foramen opticum and anterior margin of tympanic
     bulla; breadth of rostrum less than length of tympanic bulla;
     least width of palate less than medial length of P4 (except in two
     specimens); anterior margin of tympanic bulla as far posterior to
     foramen ovale as width of 3 to 5 upper incisors; height of
     tympanic bulla more than distance from its anterior margin to
     foramen ovale; length of tympanic bulla more than length of lower
     molar and premolar tooth-row and longer or shorter than rostrum;
     anterior margin of masseteric fossa not carried farther forward
     than point directly below hypoconid of m1.

     Female (based on ten adults from Sierra Nevada of California): See
     measurements and plates 33-35; weight, 2.2 (1.8-2.4) grams;
     basilar length, 38.2 (36.7-39.5); zygomatic breadth more (except
     in one specimen) than distance between condylar foramen and M1 and
     more (save in two specimens) than distance between anterior
     palatine foramen and anterior margin of tympanic bulla;
     postorbital breadth less than length of upper premolars and less
     than (except in one specimen) width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite;
     least width of palate more or less than either outside or inside
     length of P4 but generally less than inside length; tympanic bulla
     as far posterior to foramen ovale as width of 3 to 5-1/2 upper
     incisors; height of tympanic bulla more or less (usually more)
     than distance from its anterior margin to foramen ovale; length of
     tympanic bulla more than length of lower molar and premolar
     tooth-row and more or less than length of rostrum.

     The skull of the female averages 41 per cent lighter than that of
     the average male.

Compared with the skull of _M. f. longicauda_, that of both sexes
averages smaller in every measurement taken. Males of _nevadensis_, on
the average, relative to the basilar length, are narrower in the
interorbital region and across the zygomata but have the orbitonasal
length greater. Stated in another way, the rostrum of _longicauda_
appears to be shorter and broader and the zygomata are more expanded.
Females of _nevadensis_, on the average, relative to the basilar length
are narrower across the mastoid processes and zygomata and have the
braincase deeper at the anterior margin of the basioccipital. Also in
_nevadensis_ the mastoid processes do not project so far laterally
beyond the braincase, the lambdoidal crest and postorbital processes
are less well developed and except in the interparietal region, the
temporal ridges hardly meet and they form a sagittal furrow rather than
a low sagittal crest which characterizes adult females of _longicauda_.
Each of these differences separating the females of _longicauda_ from
those of _nevadensis_ are of the same nature, although not necessarily
of the same degree, as those which appear in _longicauda_ with
increasing age. The differences mentioned above are readily appreciable
when series of specimens are compared. However, none of the differences
is of great degree, and most parts of the skulls of the two subspecies
are of similar relative proportions. Even so, there is but little
overlap in actual size. Comparisons with the skulls of _M. f.
oribasus_, _alleni_, _neomexicana_, _arizonensis_, _inyoensis_,
_pulchra_, _xanthogenys_, _munda_, _saturata_, _oregonensis_,
_washingtoni_, _altifrontalis_, and _effera_ are made in the accounts
of those subspecies.

_Remarks._--The populations to which the name _nevadensis_ at present
is assigned have gone by the name _arizonensis_ since Mearns proposed
this name in 1891. Before that time Coues (1877:141) had included
individuals of this race under the name _Putorius longicauda_.

Among the populations here assigned to _M. f. nevadensis_, there is
some geographic variation but it is of lesser degree than in most other
species of mammals which range over the same region. Comparison of 20
adult males from the Rocky Mountains of Colorado with 25 adult males
from a place as far distant as the Sierra Nevada of California shows
that the two populations closely resemble each other. The specimens
from Colorado average a trifle wider across the zygomata, have a longer
body and therefore relatively shorter tail, and, except in southern
Colorado, a slightly longer hind foot. Comparison of ten adult females
from each of the two areas reveals that those from Colorado have a
markedly longer hind foot, and a tail somewhat shorter relative to the
length of the body. The mentioned differences are the only ones found
among the great number of points investigated, except that as remarked
by Merriam (1896:23) the Sierran animal has the yellow of the
underparts reaching farther up under the chin, the underside of the
tail on the average is more suffused with yellowish and the white on
the upper lip is more extensive. As regards the last mentioned feature,
my check of 34 skins from Colorado reveals that the white extends all
the way around the upper lip in every specimen but one, whereas in 69
specimens from the Sierra Nevada the white extends all the way around
the upper lip in only 39. However, as further remarked by Merriam
(_loc. cit._), not only this but the other color features are
inconstant in addition to being slight. When the occurrence of the dark
spots near the angles of the mouth are tabulated, it is found that in
33 Colorado-taken specimens they are absent in 19, faintly indicated in
13, and well developed in 1. In 62 California-taken specimens they are
absent in 37, faintly indicated in 20, and well developed in 5.

In northwestern Colorado, southern Wyoming, and possibly through the
Bear River Divide into southeastern Idaho, long-tailed weasels here
referred to _nevadensis_ approach _longicauda_ in large size and
occasionally in other features, more closely than do specimens of
_nevadensis_ from most other places in its range. This tendency is
thought to be significant for much of the area in question lies in or
below the Transition Life-zone, the same life zones in which farther to
the eastward true _longicauda_ occurs.

One specimen that illustrates this approach to _longicauda_ is an adult
male, no. 2334, collection of E. R. Warren, from 6160 feet, Lay, Routt
[now Moffat] County, Colorado. In large size and, relative to the
basilar length, shorter rostrum and shorter tympanic bullae, it agrees
with _longicauda_ but the darker color and, relative to the basilar
length, narrowness of the rostrum, interorbital region, zygomatic
expanse and the shallowness through the region of the postorbital
processes place it with _nevadensis_. Of two other specimens from
Steamboat Springs, Routt County, a young male, no. 4010, in the
collection of E. R. Warren, has a hind foot (50 mm.) as long as in
_longicauda_; and the other, no. 138195, U. S. Nat. Mus., an adult
male, agrees well enough in size and proportions with _nevadensis_ but
has the coloration typical of _longicauda_.

From Wyoming, one subadult female, no. 177553, U. S. Nat. Mus., from
Garrett, is intermediate in size and coloration but is nearer to
_nevadensis_ in these particulars, as it is in all other points
considered except size of the molar teeth which are as large as in
_longicauda_ and larger than in any female _nevadensis_ from Colorado
or California. Another female, an adult, no. 179304, U. S. Nat. Mus.,
from Lonetree, Wyoming, agrees with _longicauda_ in size of skull.
Indeed, ten of seventeen cranial measurements exceed the maximum for
Colorado-taken _nevadensis_. Where differences exist in relative
proportions of the skull as expressed in percentages of the basilar
length, the specimen approaches _nevadensis_ in 5 instances and
_longicauda_ in only 3. The color is intermediate but much nearer that
of _nevadensis_ with which the animal agrees also in external
measurements. Ten subadults (5 of each sex) from within 12 miles of
Laramie (not Fort Laramie) show greater resemblance to _nevadensis_ but
definitely approach _longicauda_. Average external measurements are:
[M], 408, 155, 44; [F], 361, 134, 40. The two other specimens examined
from this general locality, a young female, no. 2711, Mus. Vert. Zoöl.,
from Fort Bridger, and a subadult female, no. 188377, U. S. Nat. Mus.,
from Bridger Pass, show no departures from _nevadensis_ of similar age.

The specimens from scattered localities in the Transition Life-zone of
northwestern Colorado and southern Wyoming are larger than _nevadensis_
is elsewhere, and also in certain other features resemble _longicauda_
of the plains to the eastward. Everything considered, the animals in
question are much more like _nevadensis_ than _longicauda_. Study of
more specimens, especially from Wyoming, might provide grounds for
recognizing as a different subspecies the animals in this large area
comprising parts of Colorado and Wyoming from which so few specimens
now are available. Possibly the name _Putorius culbertsoni_ Coues would
apply. Decision on that point will require adequate material from the
type locality, Fort Laramie. See discussion of this name under _M. f.
longicauda_.

In southeastern Idaho males are larger than they are at most other
places within the range of _nevadensis_. An average of 7 adults and
subadults from Pegram, Montpelier, Springfield, and the vicinity of
Pocatello, reveals, when compared with the average of _nevadensis_ from
Colorado and that of _longicauda_ from the Great Plains, that this
population from southeastern Idaho is nearest to _longicauda_ in linear
measurements of the orbitonasal length, mastoid breadth, length of
tympanic bullae, and as expressed in percentage of the basilar length,
length of tooth-row, breadth of rostrum, and zygomatic breadth. In all
other points of size, relative proportions and color, the animals
approach nearer to, or actually agree with, _nevadensis_.

The specimens commented upon clearly show intergradation between
_nevadensis_ and _longicauda_. Similarly, the specimens from
Scottsbluff County, Nebraska, here referred to _M. f. alleni_, by their
larger size suggest intergradation of that subspecies with the larger
_nevadensis-longicauda_ stock although the approach is more toward
_longicauda_ than _nevadensis_. Between _oribasus_ and _nevadensis_,
however, there is no lack of material showing intergradation. As set
forth in the account of _oribasus_, specimens from Montana are truly
intermediate structurally as well as geographically.

Intergradation with _washingtoni_ is shown by specimens from the
northern part of the Cascade Range in Chelan and Okanogan counties,
Washington. The adult male, U. S. Nat. Mus., no. 235183, from Bald
Mountain, is referable to _washingtoni_ on the basis of cranial
characters but all the other adult and subadult specimens examined from
Chelan and Okanogan counties are nearer _nevadensis_ on the basis of
cranial characters. Indeed, some show no approach to _washingtoni_ in
cranial characters. As might be expected on geographic grounds, the
specimen from Easton, U. S. Nat. Mus., male subadult, no. 116870, shows
approach to _washingtoni_. This is true of the coloration of the hind
limbs, small size of the tympanic bullae, and relatively greater length
of the preorbital part of the skull. However, the greater width of the
light color of the underparts and relatively great breadth across the
mastoid processes and zygomatic arches are points of agreement with
_nevadensis_. Similarly, a series of 7 specimens from the Entait River,
20 miles above its mouth, in tone of color is nearer to _washingtoni_,
as is one of the two skulls of adult males in length of the preorbital
region. However, in greater breadth of the skull otherwise, and in the
relatively great width of the light color of the underparts, the
animals are nearer to _nevadensis_, to which they are here referred.
Some of these characters mentioned above in which departure is shown
from typical _nevadensis_ are characters that show approach to
_altifrontalis_. This is especially true of the more intense coloration
and restriction of the color of the underparts.

Complete intergradation with _effera_ is shown by specimens from
southern Oregon. The change from small _effera_ to the larger
_nevadensis_ here is gradual; consequently in northeastern California
and southern Oregon the size increases gradually to the northward.
Specimens showing complete intergradation with _oregonensis_ and
_saturata_ are wanting. However, one specimen from Crescent Lake
suggests _oregonensis_ in having near (18) apricot yellow underparts
such as occur frequently in _oregonensis_. Also some specimens from
northern California approach _saturata_ in having the color of the
underparts reduced in the extent to which it reaches out on the under
side of the tail. This fact and the consideration that the two races
are less different from one another than are other kinds which
definitely are known to intergrade leave no doubt but that material
from the intervening localities would show complete intergradation.

Intergradation between _nevadensis_ and _munda_ is indicated by
specimens from South Yolla Bolly Mountain, Trinity County, which are
commented on at greater length in the account of _M. f. munda_. _M. f.
inyoensis_ is so closely related to _nevadensis_ as to leave no doubt
that specimens from suitable localities will show actual
intergradation. That intergradation occurs directly with the bridled
weasel of the interior valleys of California, _M. f. xanthogenys_, is
shown by specimens from along the west-facing flank of the southern
part of the Sierra Nevada. Probably intergradation occurs all along the
Sierra Nevada on the western slope but specimens are lacking to show
this. Weasels are known to occur in the foothill territory and the
lesser attention given to this region by mammal collectors than to the
higher parts of the mountains may explain the lack of preserved
specimens. Individual specimens, here referred to _nevadensis_, but,
showing varying degrees of approach to _xanthogenys_ are as follows: A
female from Hume; a male and a female from 8000 feet elevation, Monache
Meadows; a male from 9800 feet elevation on the east fork of the Kaweah
River; and 7 specimens, probably one family, from one-half mile south
of Mineral King, 7850 feet. Of the specimens from 7850 feet, the adult
male has no light facial markings and the head is only slightly darker
than the back. The adult female has much restricted, light facial
markings and the intervening areas are darker than in the male. The
five juveniles trapped in the same burrow as the female, each has more
extensive light facial markings than the adult female although the area
of this varies from only slightly more than in the female to as much as
in typical specimens of _xanthogenys_. Also, the dark color of the head
in these five specimens averages darker than in _nevadensis_ and more
as in weasels to the southwestward especially _latirostra_. One of the
five juveniles is lighter colored over all of the upper parts than
_nevadensis_ and is suggestive of _xanthogenys_ in this respect.
Finally, the adult male has on the underparts small spots of ochraceous
orange suggestive of _latirostra_ and some individuals of _pulchra_.
No. 30655/42628, U. S. Nat. Mus., taken on Mount Whitney, also shows
white facial markings and some other features of the valley-inhabiting
_xanthogenys_. A suggestion of intergradation with _arizonensis_ is
furnished by specimens, referred to that race, from Springerville and
the Kaibab Plateau. No specimens happen to be available from the region
in which intergradation would be expected between _nevadensis_ and
_neomexicana_. Since _neomexicana_ and _arizonensis_ intergrade it is
probable that _nevadensis_ also will be found to intergrade with
_neomexicana_. In summary, _nevadensis_ is judged to intergrade with
each of the subspecies of _Mustela frenata_ whose range adjoins that of
_nevadensis_.

This subspecies is remarkably free from injury to the frontal sinuses
such as result from the presence of parasites. In 98 adults from
Oregon, California, Nevada, and Colorado, no malformation was noted.
Only 1 of the 26 specimens from Washington was malformed and it was an
intergrade with _washingtoni_. The single adult from New Mexico was
diseased, as were 3 of the 6 from British Columbia, 1 of the 20 from
Idaho, and 1 of the 7 from Utah.

     _Specimens examined._--Total number, 568, arranged alphabetically
     by provinces and states and from north to south by counties in
     each state. Unless otherwise indicated specimens are in the
     collection of the United States National Museum.

     =Arizona.= _Apache County_: 15 mi. E Luka Chu Kai Navajo School,
     8000 ft., 2.

     =British Columbia.= Monte Cr., 20 mi. E Kamloops, 1[21]; Sicamous,
     2; Okanagan, 18 (7[2], 6[85], 1[75], 1[86]); Monashee Pass, 1[31];
     Swan Lake, near Okanagan Landing, 1[22]; Okanagan Landing, 11
     (2[74], 3[31], 3[86], 3[22]); Vernon, 1[74]; Hope-Princeton
     Summit, 5600 ft., 1[77]; Hope, 1[20]; Similkameen, 1[77];
     Osoyoos-Bridesville Summit, 1[77]; Anarchist Mt., Osoyoos, 1[31];
     Myer's Creek, 1[77]; Rossland, Mt. Glory, 7000 ft, 1[77]; Cascade,
     1[77]; Nelson, 1.

     =California.= _Siskiyou County_: Hornbrook, 1; Tule Lake Refuge,
     5[74]; Upper Mud Creek, 6700 ft., Mt. Shasta, 3; Mt. Shasta, 1.
     _Modoc County_: Goose Lake, 1[20]; Joseph Creek, 1[74]; 5280 ft.,
     Parker Creek, near Alturas, 1[74]; Warner Mts., near Alturas,
     1[8]; 5 mi. NW Eagle Peak, 7000 ft., 2[74]; Shields Creek, 5000
     ft., 1[74]; Jess Valley, 1[8]. _Shasta County_: Cassel, 1. _Lassen
     County_: 3 mi. W Eagle Lake, 5800 ft., 1[74]; 4 mi. S Eagle Lake,
     6000 ft., 2[74]; Mill Creek, 5000 ft., S base Mt. Lassen, 1; 6 mi.
     SW Calneva, 1. _Tehama County_: Dale's, 600 ft., on Paines Creek,
     1[74]. _Plumas County_: Kelly's, 2 mi. S Willow Lake, 5200 ft.,
     3[74]; Quincy, 4[68]; Beckwith, Sierra Valley, 1. _Butte County_:
     Jonesville, 1[74]. _Sierra_ _County_: Little Truckee River, 6500
     ft., 3 mi. N Independence Lake, 2[42]. _Nevada County_:
     Independence Lake, 1[74]. _Placer County_: Donner, 3; 2 mi. W Soda
     Springs Station, 6500 ft., 1[74]; Blue Canyon, 5000 ft., 2
     (1[74]); 4 mi. S Tahoe City, 1[74]. _Eldorado County_: 5 mi. S
     Tallac, 6300 ft., 1; Gilmore Lake, Mt. Tallac, 2[74]; Mt. Tallac,
     1[68]; Phillips, 1[59]. _Alpine County_: 8000 ft., Hope Valley, 1;
     8000 ft., Silver Creek, 1. _Tuolumne County_: Strawberry, 5200
     ft., 1[74]; 9300 ft., Ten Lakes, Yosemite Park, 1[74]; Tuolumne
     Meadows, 8600 ft., Yosemite Park, 1[74]; Tuolumne Meadows (Soda
     Springs), 1; Tuolumne Meadows, 8500 ft., Yosemite Park, 1[74];
     Sequoia, 1. _Mariposa County_: Chinquapin, 6256 ft., 2[74]; Merced
     Grove Big Trees, 5400 ft., 1[74]; Wawona, 1; no locality more
     definite than county, 1. _Madera County_: Bass Lake, 1[74]. _Mono
     County_: Tioga Crest, near Tioga Pass, 4[74]; Warren Creek, 1[74];
     Tioga Lake, 1[74]; Ellery Lake, 9600 ft., 1[74]; Mono Lake P. O.,
     Mono Lake, 1[74]; Walker Lake, 8000 ft., 2[74]; Pine City, 1;
     Mammoth, 13 (12[59], 1[14]); 10300 ft., near Big Prospector
     Meadow, White Mts., 2[74]. _Inyo County_: Little Onion Valley,
     7500 ft., 1[74]; N Fork Bishop Cr., 10500 ft., 1[74]; S fork
     Bishop Cr., Andrews Camp, 8000 ft., 1[74]; South Lake, S Fk.
     Bishop Cr., 9750 ft., 1[74]; Lamarck Cr., 9900 ft., 15 mi. SW
     Bishop, 1[74]. _Fresno County_: Hume, 1. _Tulare County_: Mt.
     Whitney, 2; Whitney Meadow, 9800 ft., 1[74]; Monache Meadow, 8000
     ft., 3[74]; E fork Kaweah River, 9800 ft., 1; 1/2 mi. S Mineral
     King, 7850 ft., 7[52]; Quaking Aspen Meadow, 7500 ft., 1[52].

     =Colorado.= _Moffat County_: Lay, 1[19]. _Routt County_: Steamboat
     Springs, 2 (1[19]); no locality more definite than county, 1[57].
     _Jackson County_: Higho, North Park, 8400 ft., 1; Buffalo or
     Illinois Creek, "near Rand," 6[74]. _Washington County_: 6 mi. NE
     Hillrose, 1[74]. _Larimer County_: Estes Park, 2 (1[2], 1[7]);
     Pinewood, 1; Loveland, 2 (1[57]); no locality more definite than
     county, 1[7]. _Rio Blanco County_: Compass Creek, 9000 ft., 1[2];
     White River, 6200 ft., 1[21]; Piceance Creek, 6200 ft., 1[2]; Dry
     Fork, 6200-6600 ft., 4[2]; Meeker, 1; Marvine, 1[74]. _Grand
     County_: Crembling [= Kremmling?], 1[50]; Middle Park, 1[57].
     _Boulder County_: Foot Mt. Meeker, 8700 ft., 1[2]; Silver Lake
     Mine, 1[60]; Boulder, 1[60]; Dixie Lake, 2 (1[2], 1[57]); Caribou,
     1[2]; no locality more definite than county, 1. _Clear Creek
     County_?: Grays Peak, 1[93]. _Jefferson County_: 7000 ft., Mt.
     Parks, 1[57]; 6 mi. W Denver, 1[57]. _Adams County_: Barr, 1[2];
     near East Lake, 2[57]. _Denver County_: Denver, 2 (1[2], 1[74]).
     _Arapahoe County_: Littleton, 1[19]. _Summit County_:
     Breckenridge, 1[57]. _Eagle County_: Eagle, 9500 ft., 1[104].
     _Park County_: Jefferson, 4 (1[2]); 12800 ft., Mt. Bross, 1[57].
     _Mesa County_: Tunnel, 1. _Montrose County_: near Crawford, Clear
     Fork of Smiths Fork, 1[19]; Coventry, 3 (1[19]); Naturita, 1;
     Paradox, 1[94]; West Paradox Valley, 1[57]. _Pitkin County_:
     Placita, 2[26]. _Gunnison County_: Marble, 1[26], Crested Butte,
     2[19]; Deckers Ranch, Crested Butte, 2[19]; Sapinero, 7245 ft.,
     1[19]. _Chaffee County_: Buena Vista, 1[76]; Hancock, 1[16];
     Salida, 5[19]. _Teller County_: Glencore, Pikes Peak, 1[76]. _El
     Paso County_: Monument, 1[76]; Seven Lakes, 1[19]; Lake Moraine,
     10250 ft., 1[19]; Colorado Springs, 6000 ft., 1[19]; 5 mi. E Sand
     Creek, Colorado Springs, 1[19]; no locality more definite than
     county, 1[50]. _Saguache County_: Villa Grove, 1[19]; Pierce
     Place, Cochetopa Nat. Forest, 1; Houselog Creek, Cochetopa Nat.
     Forest, 1; P. Tevebaugh's Ranch, near Cochetopa Pass, 1; P.
     Tevebaugh's Ranch, 9 mi. S Cochetopa Pass, 1. _Rio Grande County_:
     between Monte Vista and Del Norte, 1[88]. _Archuleta County_:
     Upper Navajo River, 2[57]; Navajo River, 5 (4[57], 1[2]); Chromo,
     2[57]. _Conejos County_: Osier, 3[57]. _Montezuma County_: Ure
     Peak, 1[57]. _County_ in question: Del Norte Peak, 1[76]; no
     locality more definite than state, 4[75].

     =Idaho.= _Latah County_: Cedar Mt., 4000 ft., 12 mi. NE Moscow,
     1[55]; Moscow and 1/2 mi. W, 2[97]. _Idaho County_: Lochsa River
     (= Locksaw Fork), 1; between Selway Riv., and S Fork Clearwater
     Riv., 8[74]; Selway Divide, 8[74]; Pilot Creek, 2[74]; Newsome
     Cr., 1[74]. _Lemhi County_: Salmon River Mts., (now Lemhi Mts.),
     8000 ft., 5; Leadore, 3. _Adams County_: summit Smith Mt., 7500
     ft., 1[41]. _Washington County_: Midvale, 2. _Custer County_:
     Pahsimeroi Mts., 1; Double Springs, 16 mi. NE Dickey, 1[74];
     Mackay?, 1; Stanley Lake, 1. _Payette County_: 2 mi. S Payette,
     1[74]. _Fremont County_: 17 mi. E, 4 mi. N Ashton, 6275 ft.,
     2[74]. _Teton County_: 3 mi. S Victor, 1[74]. _Jefferson County_:
     20 mi. W Camas, 1. _Blaine County_: Sawtooth City, 1; Ketchum, 5
     (3[50], 2[75]). _Canyon County_: Nampa 3. _Clark County_: Dry
     Creek, Targhee Nat. Forest, 1[2]; Birch Creek, 2. _County_ in
     question: North fork of Teton River, 1. _Bingham County_: Shelley,
     1; Alridge, 2; Springfield, 1. _Lincoln County_: Shoshone, 1.
     _Minidoka County_: 1/4 mi. E Heyburn Bridge, 1[74]. _Power
     County_: 4 mi. NW American Falls, 1[74]. _Bannock County_: 3 mi. N
     Schutt's Mine, Ross Creek, 1[74]; 3 mi. N Pocatello, 1[74]; near
     (within 10 miles of) Pocatello, 1[74]; 3 mi. S Pocatello, 1[74]; 1
     mi. E Portneuf, 1[74]; 2 mi. up Mink Creek, 2 (1[74], 1[41]);
     Inkom, 2; Swan Lake, 1. _Owyhee County_: 5 mi. SE Riddle, 1; Three
     Creek, 2. _Cassia County_: Elba, 1[52]. _Bear Lake County_:
     Geneva, 6171 ft., 1[74]; Montpelier, 1; Paris, 6000 ft., 1[6];
     Pegram, 2.

     =Nevada.= _Humboldt County_: Alder Creek, 7000 ft., Pine Forest
     Mts., 1[74]; head of Big Creek, 8000 ft., Pine Forest Mts., 1[74];
     Cottonwood Range, 1; Calico Mt., Little Owyhee R., 1; Mahogany,
     Little Owyhee R., 2; Sulphur, 1. _Pershing County_: Lovelocks, 1.
     _Elko County_: Mountain City, 3; Three Lakes, Ruby Mts., 1[41].
     _Washoe County_: Pyramid Lake, 1; 3 mi. E Reno, 1[74]; Incline
     Creek, 7100 ft., 1[74]; 2-1/2 mi. S Incline, 6250 ft., 1[74]; E
     side Marlette Lake, 8000 ft., 1[74]; Marlette Lake, 8000 ft.,
     1[74]. _Ormsby County_: 1/2 mi. S Marlette Lake, 8150 ft., 1[74].
     _Churchill County_: 4 mi. W Fallon, 1[74]; 3 mi. W Fallon, 1[74];
     2 mi. W Fallon, 1[74]; Fallon, 3970 ft., 1[74]. 5 mi. S Fallon,
     4000 ft., 1[74]; 8 mi. S and 3 mi. E Fallon, 1[74]. _Douglas
     County_: Mt. Siegel, 1[60]. _Mineral County_: Lapon Cañon, 8900
     ft., Mt. Grant, 1. _Nye County_: Arc Dome, 1; 10700 ft., 1/2 mi.
     SW Jefferson Peak, Toquima Range, 1[74]. _White Pine County_: 3
     mi. E Baker, 1[74]; Baker Creek, 6600 ft., 4[74]; Baker Creek,
     8400 to 8450 ft., 4[74]; Gleason Creek, 7500 ft., 1[74].
     _Esmeralda County_: Arlemont, 4850 ft., Fish Lake Valley, 1[74].
     _Lincoln County_: 3 mi. S Crystal Spring, 3900 ft., Pahranagat
     Valley, 1[27].

     =New Mexico.= _Taos County_: 2 mi. N Twining, 10500 ft., 1; Taos,
     2. _Santa Fe County_: 11600 ft., Pecos Baldy, 1. _San Miguel
     County_: 8000 ft., above Willis, Pecos River, Forest Reserve,
     2[75]; Ribera, 1.

     =Oregon= (by counties from west to east). _Jackson County_:
     Rustler Peak, Crater Nat. Forest, 1[46]; Siskiyou (probably south
     of), 2. _Klamath County_: 20 mi. W Crescent, 1[101]; Anna Creek,
     Mt. Mazama, 2; S Boundary Crater Lake Nat. Park, 1[74]; Fort
     Klamath, 15; Upper Klamath Lake, 2[4]; Klamath Falls, 1[75]. _Lake
     County_: Dog Lake Ranger Station, 30 mi. SW Lakeview, 1. _Harney
     County_: Camp Harney, 2[75]; Burns, 2 (1[101]); 20 mi. S Burns,
     1[46]; Narrows, 1[59]; Voltage, 1; Shirk P. O., 2; Keiger Gorge,
     Steen Mts., 4. _Malheur County_: Riverside, 1; 2 mi. NW Riverside,
     2; Barren Valley, Cord, 1; Cedar Mts., 2; Cow Creek Lake, 1;
     Jordan Valley, 1. _County_ in question: Sageview, 1.

     =Utah.= _Cache County_: Logan, 1[74]. _Rich County_: 8000 ft.,
     near Laketown, 1. _Boxelder County_: Willard, 1[103]. _Salt Lake
     County_: Salt Lake City, 1[74]; Barclay, 6500 ft., Wasatch Mts.,
     1; Mill Creek, 1[103]. _Utah County_: Provo Bench, 2[6]; Aspen
     Grove, Mt. Timpanogos, 1[6]; Payson, 1[6]. _Juab County_: between
     Santaquin and Starr, 1[103]. _Uinta County_: Dry Fork Canyon, 20
     mi. NW Vernal, 1[9]. _Carbon County_: Sunnyside, 1[44]; Range
     Creek, 1[44]. _Millard County_: Deseret, 1[74]. _Sevier? County_:
     Fish Lake Plateau, 1. _Grand County_: Warner Ranger Station, La
     Sal Mts., 1[6]. _Beaver County_: Britts Meadows, 11000 ft., Beaver
     Range, 1[2]; Britts Meadows, Beaver Range, 1; Puffer Lake, 1[44].
     _Garfield County_: Boulder, 2[6]. _Washington County_: Pine
     Valley, 1[44]; St. George, 1. _San Juan County_: Geyser Pass, La
     Sal Mts., 2[6]. _County_ in question: Salt Lake, 2; Wasatch Mts.,
     1; La Sal Mts., 11000 ft., 1.

     =Washington.= _Okanogan County_: Bald Mt., 6800 ft., 1; Bauerman
     Ridge, 6800 ft., Tungsten Mine, 1; Hart Pass, Methow River Trail,
     1[46]; Conconully, 2 (1[51], 1[49]); 5 mi. NW Loomis, 1; Molson,
     3800 ft., 1; Tunk Mt., 3500 ft., 1. _Whatcom County_: Barron, 5000
     ft., 1. _Stevens County_: Colville, 1; Orin, 11[51]. _Pend Oreille
     County_: Ione, 6[51]. _Chelan County_: Chelan Mts., 1[2]; Lake
     Chelan, 1[46]; Manson, 1; Entiat River, 1680 ft., 20 mi. from
     mouth, 7; Dryden, 2[49]; Wenatchee, 1. _Kittitas County_: Easton,
     2 (1[51]); Ellensburg, 1[51]; 4 mi. E Ellensburg, 1[51]. _Grant
     County_: Neppel, 1[51]. _Lincoln County_: Sprague, 1. _Spokane
     County_: Spokane, 1[94]; Cheney 2[89]. _Whitman County_: Pullman,
     11 (6[55], 1[68], 1[10]); 6 mi. S Pullman, 1. _Garfield County_:
     Snake River, 1. _Yakima County_: Yakima, 1[74]; 1 mi. W Moxee,
     1[74].

     =Wyoming.= NW Wyoming, 1[75]. _Yellowstone National Park_: Lamar
     River, 1; Yellowstone Lake, 1. _Park County_: Greybull River,
     1[80]. _Teton County_: Crystal Creek, 2; Jackson, 1; Whetstone
     Creek, 2[76]. _Johnson County_: Buffalo, 4 (2[93]). _Fremont
     County_: Continental Divide, 20 mi. NW Dubois, 1[75]. _Sublette
     County_: Bronx, 1[75]. _Carbon County_: Medicine Bow Mts., 1[75];
     15 mi. SE Parco, 1[74]. _Albany County_: Garrett, 1; 12 mi. W
     Laramie, 1[74]; 7 mi. W Laramie, 2[74]; 5 mi. W Laramie, 4[74];
     "near" Laramie, 1[74]; 3 mi. SW Laramie, 1[74]; 12 mi. S Laramie,
     1[74]. _Uinta County_: Fort Bridger, 6800 ft., 1[74]; Lonetree, 1;
     Bridger Pass, 1. _County_ in question: Laramie River, 2. No
     locality more definite than state, 1.


=Mustela frenata effera= Hall

Long-tailed Weasel

Plates 19, 20 and 21

    _Mustela frenata effera_ Hall, Carnegie Instit. Washington Publ.
      473:93, November 20, 1936.

    _Mustela arizonensis_, Dice, Journ. Mamm., 1:12, November 28, 1919.

     _Type._--Male, adult, skull and skin; no. 33637, Amer. Mus. Nat.
     Hist.; Ironside, 4000 ft., Malheur County, Oregon; September 8,
     1912; obtained by H. E. Anthony; original no. 267.

     The skull (plates 19-21) is complete and unbroken. The teeth all
     are present and entire. The skin, in summer pelage, is well made.

     _Range._--Upper Sonoran to Arctic Alpine life-zones of northern
     two-thirds of Oregon east of the Cascades, and southeastern
     Washington, south of the Snake River. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     nevadensis_ in small size, males averaging 12-1/2 per cent smaller
     in external measurements, 8 per cent smaller in linear
     measurements of skull, and 22 per cent in weight of skull, total
     length averaging 360 rather than 400, condylobasal length
     averaging 40.5 rather than 43.6; from _M. f. oregonensis_ in
     absence of frontonasal white patch, presence of light color of
     underparts on ventral face of tail and smaller skull with basilar
     length averaging less than 41.7 in males; from _M. f. washingtoni_
     in presence of light color of underparts on ventral face of tail,
     in male skull by linear measurements averaging 7 (5-12) per cent
     shorter and relative to basilar length shorter in preorbital
     region and broader across mastoid processes and zygomatic arches.

     _Description._--_Size._--Male: Eight (6 adult and 2 subadult)
     males from northeastern Oregon yield average and extreme
     measurements as follows: Total length, 360 (340-378); length of
     tail, 129 (122-136); length of hind foot, 42 (40-44). Tail
     averages 56 (52-59) per cent as long as head and body. Length of
     hind foot more or less than (about same as) basal length.

     Female: No. 212423 from Vale, and no. 566 V. B. Scheffer, from 15
     mi. E Ukiah, measure, respectively: Total length, 312, 306; length
     of tail, 113, 114; length of hind foot, 35, 35. Tail averages 57
     per cent as long as head and body.

     Differences in external measurements between the one adult female
     and the average of the males are: Total length, 51; length of
     tail, 16; length of hind foot, 7.

     _Externals._--Longest facial vibrissae black, brown or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles (in summer
     pelage) about as shown in stage 4 of figure 19.

     _Color._--Upper parts, in summer, near (14 _n_ to _l_) Brussels
     Brown or tones 1 to 3 of Raw Umber of Oberthür and Dauthenay, pl.
     301, darker on top of head from nose to, or slightly behind, line
     connecting posterior margins of ears. Chin and usually all of
     upper lips white. Remainder of underparts Buff-Yellow to Straw
     Yellow. In winter all white except tip of tail or upper parts near
     (_j_) Snuff Brown or lighter than Brussels Brown with a smoked
     effect, with underparts white. Tip of tail at all times black.
     Color of underparts extends distally on posterior sides of
     forelegs over toes onto antipalmar faces of toes and wrists, on
     medial sides of hind legs to ankles over antiplantar faces of
     toes, distomedial third of tarsus and usually over proximal fourth
     to three-fourths of ventral side of tail. Least width of color of
     underparts averaging, in 15 males, 53 (36-69) per cent of greatest
     width of color of upper parts. Black tip of tail averaging 47
     (38-67) mm. long. Thus averaging longer than hind foot, and 36 per
     cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on 6 adults from northeastern
     Oregon): See measurements and plates 19-21. As described in
     _Mustela frenata nevadensis_ except that: Weight, 2.9 (2.5-3.4)
     grams; basilar length, 40.5 (39.3-41.8).

     Female (based on no. 212423, adult from Vale): In so far as parts
     of the broken skull permit a person to judge, the skull is as
     described in _M. f. nevadensis_ except that: Smaller; lighter;
     postorbital breadth more than width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite.

As compared with the skull of _M. f. nevadensis_ that of _effera_
seems, on the average, to have the preorbital part relatively smaller.
Otherwise, the skull is a miniature of the skull of _nevadensis_,
averaging about eight per cent smaller in linear measurements and
weighs twenty-two per cent less. Comparisons of the skull with those of
_M. f. washingtoni_ and _M. f. oregonensis_ are made in accounts of
those subspecies.

_Remarks._--This geographic race has long borne the name of _Mustela
arizonensis_ (Mearns). Small size differentiates _effera_ from
_nevadensis_ and specimens have been allocated to one or the other
subspecies on the basis of size, or average size when several
individuals are available from one locality. Complete intergradation
with each adjoining subspecies is indicated by numerous specimens, more
of which are assigned to these adjoining subspecies than to _effera_
itself.

The minimum of size in _M. f. effera_ is found in the Blue Mountain
region of northeastern Oregon. Specimens from the area intervening
between these mountains and the Cascades average larger but are nearer
the mean of typical _effera_ than they are to the means of
_washingtoni_, _oregonensis_ or _nevadensis_.

Two males, nos. 204883, adult, and 204884, young, from Sisters, Oregon,
near the eastern base of the Cascades, show approach structurally to
_M. f. washingtoni_ as it is represented at the nearby locality,
Permilia Lake, at the west base of Mount Jefferson. Everything
considered, however, the two specimens from Sisters are nearer to
_effera_. A male from Condon, Oregon, shows approach to the Cascade
race in slightly increased size.

No perfect skulls of adult females are available from the part of
northwestern Oregon in which _effera_ reaches its typical state of
development as judged by the small size of the skull of the adult male.
Skulls of adult females are available, however, from more nearly
marginal localities. These, though smaller than in _nevadensis_, show
relatively less difference in size when compared with _nevadensis_ than
do skulls of males. Even so the females at these marginal localities
are smaller than those of _nevadensis_ of comparable age and adequate
material of adult female _effera_ from the region where the males
attain their extreme of small size probably will show about the same
relative difference in size between _nevadensis_ and _effera_ as is
known to exist between the adult males of these two subspecies. The
small size of a subadult female, no 74631, U. S. Nat. Mus., from
Asotin, Washington, constitutes partial basis for this opinion.

Of 14 adults examined none showed malformation of the frontal sinuses
due to infestation by parasites.

     _Specimens examined._--Total number, 53, arranged within each
     state by counties from north to south. Unless otherwise indicated
     specimens are in the collection of the United States National
     Museum.

     =Oregon.= _Wasco County_: 4 mi. S The Dalles, 1[74]; Wapinita, 1;
     Antelope, 2; 7 mi. E Antelope, 5. _Gilliam County_: Condon, 1[46].
     _Morrow County_: 10 mi. S Hardman, 1. _Umatilla County_: Umatilla,
     2; 15 mi. E Ukiah, 4000 ft., 1[49]. _Union County_: Elgin, 1; 20
     mi. E Lehman, 1[46]. _Wallowa County_: Horse Creek, 15 mi. N
     Paradise, 1; Enterprise, 1[46]; Wallowa Lake, 1[46]; Wallowa
     Mts., 8300 ft., 1. _Baker County_: Haines, 1[49]; Anthony, 3[2];
     Bourne, 2. _Grant County_: Long Creek, 1[46]; Canyon Creek, 1[46];
     Strawberry Mts., 2; Silvies, 1[14]. _Crook County_: Prineville, 4.
     _Deschutes County_: Sisters, 2; Bend, 1. _Lake County_: 3 mi. W
     Stauffer, 1; Fort Rock, 1[46]. _Harney County_: 25 mi. NW Burns,
     1. _Malheur County_: 4000 ft., Ironside, 2[2]; 1-1/2 mi. S Vale,
     2.

     =Washington.= _Walla Walla County_: Prescott, 4 (2[76], 1[60],
     1[74]); Ft. Walla Walla, 2 (1[75]); Wallula, 1[76]. _Asotin
     County_: Asotin, 1.


=Mustela frenata washingtoni= (Merriam)

Long-tailed Weasel

Plates 19, 20, 21, 34, 35 and 36

    _Putorius washingtoni_ Merriam, N. Amer. Fauna, 11:18, pl. 4, figs.
      3, 3a, 4, 4a, June 30, 1896.

    _Mustela washingtoni_, Miller, U. S. Nat. Mus. Bull., 79:98,
      December 31, 1912.

    _Mustela frenata washingtoni_, Hall, Carnegie Instit. Washington
      Publ. 473:106, November 20, 1936.

     _Type._--Male, adult, skin and skull; no. 76322, U. S. Nat. Mus.,
     Biol. Surv. Coll.; Trout Lake, Mt. Adams, Klickitat (?) County,
     Washington; December 15, 1895; obtained by D. N. Kaegi; original
     no. 2.

     The skull is unbroken. The left incisors above are missing.
     Otherwise the teeth are present and entire. The skin is well made,
     in brown winter pelage, lacks collector's measurements, has no
     bones in the feet, but by large size is judged to be a male.

     _Range._--Altitudinally from near 2000 feet at Trout Lake up to
     the highest parts of the Cascade Range from Mount Jefferson,
     Oregon, north to Mount Rainier, Washington; Upper Sonoran
     Life-zone to Arctic Alpine Life-zone. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     altifrontalis_ in lighter color of upper parts and underparts,
     latter ranging from Buff-Yellow to Naples Yellow rather than near
     (14 _a_ to 16 _c_) Ochraceous-Buff, in shallower skull in both
     sexes (see measurements), in males, a longer preorbital region,
     narrower skull with shorter bullae, and in females, a smaller
     skull with interorbital breadth averaging less than 24 per cent of
     basilar length; from _M. f. nevadensis_ in absence of light color
     of underparts on ventral face of tail, in skulls of males, by
     longer preorbital region and narrower skull across mastoid
     processes and zygomatic arches, in skulls of females, by shorter
     preorbital region, and smaller bullae (see measurements); from _M.
     f. effera_ in absence of light color of underparts on ventral face
     of tail, in skulls of males, by linear measurements averaging 7
     (5-12) per cent larger, and relative to basilar length, longer in
     the preorbital region and narrower across mastoid processes and
     zygomatic arches; from _M. f. oregonensis_ in absence of
     frontonasal white patch, longer skull in males, which in
     percentage of basilar length has, on the average, orbitonasal
     length amounting to more than 35, mastoid breadth less than 55,
     and zygomatic breadth less than 63, and in females, smaller skull
     with least width of palate less than length of P4, upper
     tooth-rows less than 38-1/2 per cent of basilar length, bullae
     smaller, averaging less than 13.4 in length.

     _Description._--_Size._--Male: Fifteen subadult topotypes yield
     average and extreme measurements as follows: Total length, 400
     (357-437); length of tail, 149 (122-171); length of hind foot,
     47.6 (42-59). Tail averages 59 per cent as long as head and body.
     Length of hind foot averaging more than basal length.
     Corresponding measurements of one adult and 3 young from Mount
     Rainier are: 415 (405-423); 155 (145-164); 51 (50-53).

     Female: Five adult topotypes yield average and extreme
     measurements as follows: Total length, 349 (330-393); length of
     tail, 124 (114-133); length of hind foot, 38 (36-39). Tail
     averages 55 per cent as long as head and body. Length of hind foot
     averaging about same as basal length. Corresponding measurements
     of two adults and 6 young from Mount Rainier are: 338 (320-360);
     121 (115-132); 36 (34-40).

     The average differences in external measurements of the two sexes,
     from Mount Adams, are: Total length, 51; length of tail, 25;
     length of hind foot, 9.6. Corresponding differences between the
     specimens from Mount Rainier are: 77; 34; 15.

     _Externals._--Longest facial vibrissae black or brown (often both
     colors in same specimen) and extending beyond ear; carpal
     vibrissae same color as underparts and extending to or beyond
     apical pad of fifth digit; hairiness of foot-soles slightly less
     than shown in figure 19.

     _Color._--Upper parts in summer near (14 _n_) Argus Brown or tone
     4 of Burnt Umber of Oberthür and Dauthenay, pl. 304; one topotype
     Buckthorn Brown or tone 3 to 4 of Snuff Brown of Oberthür and
     Dauthenay, pl. 303. Dark spot at each angle of mouth present or
     absent, and when present, often fused with color of upper parts,
     which rarely covers lower lips. Chin, and usually lower lips,
     white. Remainder of underparts Buff-Yellow to Naples Yellow. In
     winter, all white except tip of tail which is at all times black,
     or upper parts near (14) Brussels Brown to near (_j_) Snuff Brown
     with smoked effect and underparts white, rarely with trace of
     yellowish. Color of underparts extends distally on posterior sides
     of forelegs over toes onto antipalmar faces of feet and usually
     all of wrists, on medial sides of hind legs anywhere from knee to
     tips of toes. Least width of color of underparts averaging in ten
     topotypes, 24 (10-37) per cent of greatest width of color of upper
     parts. Black tip of tail in same series averaging 55 (45-60) mm.
     long, thus longer than hind foot and averaging 37 per cent of
     length of tail-vertebrae.

     The color of the underparts is not so narrow in the specimens from
     Mount Rainier and it is believed that the slender bodies used in
     stuffing the topotypes has accentuated in them the appearance of
     narrowness of the light-colored underparts.

     _Skull and teeth._--Male (based on 22 adult topotypes): See
     measurements and plates 19-21; weight, 3.5 (2.8-4.7) grams;
     basilar length, 43.7 (40.0-47.7); zygomatic breadth more or less
     than distance between condylar foramen and M1 or than between
     anterior palatine foramen and anterior margin of tympanic bulla;
     mastoid breadth more or less than postpalatal length; postorbital
     breadth less than length of upper premolars and greater than width
     of basioccipital measured from medial margin of one foramen
     lacerum posterior to its opposite; interorbital breadth more or
     less than distance between foramen opticum and anterior margin of
     tympanic bullae; breadth of rostrum less (except in no. 82180)
     than length of tympanic bulla; least width of palate more (except
     in no. 81954) than length of P4; anterior margin of tympanic bulla
     as far posterior to foramen ovale as width of 2 to 5 upper
     incisors; height of tympanic bulla more or less than distance from
     its anterior margin to foramen ovale; length of tympanic bulla
     more (except in two instances) than length of lower molar and
     premolar tooth-row and shorter (except in two instances) than
     rostrum; anterior margin of masseteric fossa below m2.

     Female (based on 11 ad. topotypes): See measurements and plates
     34-36; weight, 2.0 (1.8-2.2) grams; basilar length, 37.6
     (37.0-38.9); zygomatic breadth less (except in no. 70945) than
     distance between condylar foramen and M1 or than between anterior
     palatine foramen and anterior margin of tympanic bulla;
     postorbital breadth less than length of upper premolars and more
     than width of basioccipital measured from medial margin of one
     foramen lacerum posterior to its opposite; least width of palate
     less (except in one specimen) than greatest length of P4; tympanic
     bulla as far posterior to foramen ovale as width of 3-1/2 to 5-1/2
     upper incisors; height of tympanic bulla more or less than
     distance from its anterior margin to foramen ovale; length of
     tympanic bulla more than length of lower molar and premolar
     tooth-row and longer or shorter than rostrum.

Compared with _M. f. nevadensis_, the skull of the male of
_washingtoni_ averages more slender, as shown by the mastoid and
zygomatic breadths and has the preorbital part longer, on the average,
as shown by the greater ratio (to the basilar length) of the length of
the tooth-rows and orbitonasal length. Also, on the average, the
postorbital constriction is longer than in _nevadensis_ and the
tympanic bullae are smaller. In females, the skull is lighter, the
tooth-rows are shorter, the tympanic bullae are smaller, and the
preorbital part of the skull is shorter and narrower as shown by the
orbitonasal length and interorbital breadth. Except that the tympanic
bullae are actually, although not relatively, smaller in males of
_effera_, it differs from _washingtoni_ in the same way as does
_nevadensis_ as regards relative proportions, but, of course, the
actual difference in size is greater since _effera_ is smaller than
_nevadensis_. Comparison of the skull with that of _oregonensis_ is
made in the account of that subspecies.

_Remarks._--_M. f. washingtoni_ was described and named in 1896 by
Merriam as a distinct species. Subsequently, specimens which here are
regarded as intergrades between _altifrontalis_ and _nevadensis_, were
classified as _washingtoni_.

The external measurements given for the specimens from Mount Adams are
those recorded on the labels in inches and fractions thereof. Instead
of total length there sometimes is written "tip to tip." In the series
of 19 winter-taken topotypes the hairs project beyond the end of the
caudal vertebrae for an average distance of 28 (19-40) millimeters. If
the hairs on the end of the tail were included in the measurements, 28
millimeters should be subtracted from the averages. Probably the
measurements should stand as given, since an adult male topotype, no.
226758, U. S. Nat. Mus., taken subsequently by Walter P. Taylor
measures 405; 152; 51.

_Mustela frenata washingtoni_ is not a strongly marked geographic race.
In many features it is intermediate between _M. f. altifrontalis_ and
_M. f. nevadensis_. This is especially true of coloration. In the
series from Mount Adams and that from Mount Rainier, some individuals
have the light color of the underparts extended down the hind legs over
the feet and over the proximal face of the ventral third of the tail as
in _nevadensis_, whereas others from the same place have the light
color of the underparts absent from the tail and extending no farther
down the hind limbs than the knees. The light color of the underparts
in the series of topotypes is so restricted that the transverse extent
at the narrowest place amounts to only 24 (10-37) per cent of the
greatest width of the color of the upper parts. This narrowness of the
color of the underparts has been likened by Merriam (1896:18) to the
condition in _Mustela frenata noveboracensis_. So it is, but it is
similar to the condition found also in the geographically adjoining _M.
f. altifrontalis_.

Of the 37 skulls of subadults and a few adults, 11 had the frontal
sinuses malformed as a result of infestation by parasites.

     _Specimens examined._--Total number, 56, arranged within each
     state by localities from north to south. Unless otherwise
     indicated specimens are in the collection of the United States
     National Museum.

     =Oregon.= Mt. Jefferson, Permilia Lake, 1.

     =Washington.= _Pierce County_: 5500 ft., Spray Park, Mt. Rainier,
     1; Spray Park, 1[74]; 5935 ft., Glacier Basin, Mt. Rainier, 5
     (1[10]); 5051 to 5100 ft., Owyhigh Lakes, Mt. Rainier, 7 (1[10]),
     Tahoma Creek, 1[72]; Nisqually entrance, 1[72]; Longmire, 1[72];
     Mt. Rainier Nat'l Park, 2[72]. _Klickitat County_: Trout Lake, S
     Base Mt. Adams, 35; 3500 ft., Gotchen Creek, Mt. Adams, 1.


=Mustela frenata saturata= (Merriam)

Long-tailed Weasel

Plates 19, 20, 21 and 30

    _Putorius saturatus_ Merriam, N. Amer. Fauna, 11:21, June 30, 1896.

    _Mustela saturata_, Miller, U. S. Nat. Mus. Bull., 79:98, December
      31, 1912.

    _Mustela arizonensis saturata_, Grinnell, Univ. California Publ.
      Zoöl., 40:102, September 26, 1933.

    _Mustela frenata saturata_, Hall, Carnegie Instit. Washington Publ.
      473:106, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 65930, U. S. Nat. Mus.,
     Biol. Surv. Coll.; Siskiyou, Jackson County, Oregon; June 6, 1894;
     obtained by C. P. Streator; original no. 3905.

     The skull (plates 19-21, 30) lacks the middle part of each
     zygomatic arch. The teeth all are present although much worn,
     probably from gnawing at the trap which captured the animal. The
     skin, in fresh summer pelage, is fairly well made.

     _Range._--Transition and Boreal life-zones of Siskiyou and Trinity
     mountains in southern Oregon and northwestern California. See
     figures 29 and 30 on pages 221 and 314.

     _Characters for ready recognition._--Differs from _M. f.
     nevadensis_ in lacking light color of underparts on tail and ankle
     and in greater average breadth across mastoid processes of skull
     (see measurements); from _M. f. oregonensis_ in lacking white
     nasofrontal spot, in having color of underparts interrupted at
     ankle; from _M. f. munda_ in lacking white nasofrontal spot, in
     smaller and relatively deeper skull of males and smaller skull of
     the female.

     _Description._--_Size._--Male: Four adult males (the type, 1 from
     Mt. Ashland and 2 from Jackson Lake) yield average and extreme
     measurements as follows: Total length, 414 (402-437); length of
     tail, 150 (136-160); length of hind foot, 46 (43-50). Tail
     averages 57 (49-62) per cent as long as head and body. Length of
     hind foot more or less than basal length.

     Female: One young from the summit of the Trinity Mountains east of
     Hoopa and one nontypical adult from 5500 feet elevation on South
     Fork Mountain, Humboldt County, measure respectively as follows:
     Total length, 330, 325; length of tail, 115, 123; length of hind
     foot, 37, 37. Tail is 53 and 61 per cent as long as head and body.
     Length of hind foot less than basal length.

     Average differences in external measurements between the two
     sexes, indicated by the unsatisfactory material available, are:
     Total length, 86; length of tail, 31; length of hind foot, 9.

     _Externals._--Longest facial vibrissae black or dark brown and
     extending beyond ear; carpal vibrissae same color as underparts
     and extending as far as apical pad of fifth digit; hairiness of
     foot-soles, in summer pelage, as shown in figure 19.

     _Color._--Upper parts, in summer, Brussels Brown to near (_n_)
     Brussels Brown or lighter than tone 3 of Raw Umber of Oberthür and
     Dauthenay, pl. 301, usually darkest on nose and forehead. Chin
     white. Remainder of underparts Buff-Yellow to Warm Buff. Tip of
     tail black. Winter pelage unknown. Color of underparts extends
     distally on posterior sides of forelegs over toes onto antipalmar
     faces of feet and sometimes wrists, on medial sides of hind legs
     only to ankles, but toes sometimes with isolated white markings.
     Least width of color of underparts in the type and 2 adults from
     Jackson Lake averaging 35 (30-40) per cent of greatest width of
     color of upper parts. Black tip of tail averaging 54 (53-55) mm.
     long; thus longer than hind foot and averaging 37 per cent of
     length of tail-vertebrae.

     _Skull and teeth._--Male (based on 4 adults: Type, Mt. Ashland, 1;
     Jackson Lake, 2): See measurements and plates 19-21, 30. As
     described in _Mustela frenata nevadensis_ except that: Weight, 3.8
     (3.5-4.3) grams; basilar length, 44.4 (42.6-45.8); zygomatic
     breadth more or less than distance between condylar foramen and M1
     or than distance between anterior palatine foramen and anterior
     margin of tympanic bulla; mastoid breadth more than postpalatal
     length; least width of palate less than medial length of P4
     (except in one specimen).

     Female (based on one adult possibly not typical, from 5500 ft.,
     South Fork Mt.): See measurements. As described in _Mustela
     frenata nevadensis_ except that: Weight, 2.2 grams; basilar
     length, 38.1; zygomatic breadth less than distance between
     condylar foramen and M1 and less than distance between anterior
     palatine foramen and anterior margin of tympanic bulla;
     postorbital breadth more than width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite.

The skull of the male of _saturata_, relative to the basilar length, is
broader across the mastoids and narrower across the rostrum and
interorbital region than that of _nevadensis_. Skull not known
certainly to differ from that of _oregonensis_. Compared with the skull
of _munda_, that of the male of _saturata_ is smaller in every part
measured except depth of tympanic bullae which averages 3.6
millimeters, rather than 3.5 as in _munda_. Also, the skull of
_saturata_ has a less-marked postorbital constriction, is less heavily
ridged, less angular, does not have the impressions of the temporal
muscles carried so far forward on the frontal bones and is relatively
much narrower across the zygomatic arches.

_Remarks._--In 1896, Merriam named _M. f. saturata_ as a distinct
species on the basis of one specimen, taken by Clark P. Streator at
Siskiyou, Oregon, and a second specimen taken the year previously by
Allan C. Brooks at Chilliwack, British Columbia. On the basis of these
two specimens, Merriam (1896:22) ascribed to the race a range ". . . on
the Cascade and Siskiyou mountains of Oregon and Washington, reaching a
short distance into British Columbia." Since that time, this name,
_saturata_, has been employed for the dark-colored weasels, of the
coastal region of Oregon, Washington, and extreme southwestern British
Columbia, which here are arranged under the name _M. f. altifrontalis_.
_M. f. saturata_ proves to be restricted to the humid mountainous
region inland from the coast in northern California and in the Siskiyou
Mountains of southern Oregon. Its range is separated by that of _M. f.
oregonensis_ from the range of the darker-colored, deeper-skulled, _M.
f. altifrontalis_ of the humid costal region proper.

On May 5, 1933, Mr. Clark P. Streator, informed the writer that he
remembered taking the type specimen of _Mustela frenata saturata_
(Merriam) in the town of Siskiyou, Oregon. The exact place, he said,
was reached, at the time of his work there, by going one or two blocks
east of the depot, then through a garden into the thick woods where
there were springs and numerous burrows of the rodent, _Aplodontia_.
Two other weasels labeled as taken at Siskiyou, on September 28 and
29, 1893, by Mr. Streator, are much lighter colored than the type of
_saturata_ and have the color of the underparts extended distally on
the hind legs to the tips of the toes and in other features of
coloration are more like _nevadensis_, the subspecies to which they are
referred, than _saturata_. Probably these did not come from exactly the
same place that the type specimen of _saturata_ did. Although Mr.
Streator does not remember the taking of these particular specimens in
1893, he does remember that on this visit to Siskiyou, he walked
southward through the railroad tunnel and collected on the opposite
side of the ridge from Siskiyou. Here on more southern exposures, the
country was markedly different than in the thick forest at Siskiyou.
Probably these two specimens taken in 1893, and referred to
_nevadensis_, came from a little way south of Siskiyou and from a
different habitat and life-zone than the type specimen of _M. f.
saturata_.

Of the 6 specimens examined, only one, the type, shows malformation of
the frontal sinuses such as result from infestation by parasites.

     _Specimens examined._--Total number, 6, as follows:

     =California.= _Siskiyou County_: Jackson Lake, 5900 ft., 2, Mus.
     Vert. Zoöl. _Humboldt County_: South Fork Mt., 5500 ft., 1, Mus.
     Vert. Zoöl. _County_ in question, Trinity Mts., summit east of
     Hoopa, 5800 ft., 1, U. S. Nat. Mus.

     =Oregon.= _Jackson County_: Mt. Ashland, 1, Univ. Oreg.; Siskiyou,
     1, U. S. Nat. Mus.


=Mustela frenata altifrontalis= Hall

Long-tailed Weasel

Plates 1, 19, 20, 21, 34, 35 and 36

    _Mustela frenata altifrontalis_ Hall, Carnegie Instit. Washington
      Publ. 473:94, November 20, 1936.

    _Putorius (Gale) brasiliensis frenatus_, Coues, Fur-bearing
      animals, p. 142, 1877 (part).

    _Putorius saturatus_ Merriam, N. Amer. Fauna, 11:21, June 30, 1896
      (part).

    _Mustela saturata_, Miller, U. S. Nat. Mus. Bull., 79:98, December
      31, 1912.

     _Type._--Male, adult, skull and skin; no. 42093, Mus. Vert. Zoöl.;
     Tillamook, Tillamook County, Oregon; July 10, 1928; obtained by
     Alex Walker; original no. 717.

     The skull is complete and unbroken. P3 on the left side is
     missing; otherwise the teeth all are present and entire. The skin
     is well made and the enlarged scrotal pouch shows the collector's
     sexing of the specimen to have been correct.

     _Range._--Altitudinally from sea level up to at least 4800 feet
     (Mount Baker) in the Transition Life-zone of the humid, coastal
     region of Oregon, Washington and extreme southwestern British
     Columbia. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f.
     nevadensis_ in tone 4 of Brownish Drab, pl. 302, rather than tones
     1-3, of Raw Umber, pl. 301, of Oberthür and Dauthenay of upper
     parts, in near (14 _a´_ to 16 _c´_) Ochraceous-Buff rather than
     Buff-Yellow to Straw Yellow of underparts, in that least width of
     color of underparts amounts to less than 37 per cent of greatest
     width of color of upper parts, in absence of color of underparts
     on ventral side of tail and on hind leg distal to knee, and in
     greater depth of skull through frontal region; from _M. f.
     washingtoni_ in darker color of upper parts and underparts, latter
     near (14 _a_´ to 16 _c_´) Ochraceous-Buff rather than ranging from
     Buff-Yellow to Naples Yellow, in deeper skull in both sexes (see
     measurements), in males a shorter preorbital region, broader skull
     with longer bullae and in females a larger skull with interorbital
     breadth averaging more than 24 per cent of basilar length; from
     _M. f. oregonensis_ in frontonasal white patch absent, color above
     darker (tone 4 of Brownish Drab, pl. 302, rather than tone 2 to 3
     of Raw Umber, pl. 301 of Oberthür and Dauthenay), light-colored
     underparts narrower and not extended distally beyond knee, in
     females tooth-row shorter, amounting to less than 38 per cent of
     basilar length.

     _Description._--_Size._--Male: Eight adult topotypes yield average
     and extreme measurements as follows: Total length, 426 (392-445);
     length of tail, 160 (148-170); length of hind foot, 47 (42-53).
     Tail averages 60 per cent as long as head and body. Length of hind
     foot averages more than basal length.

     Female: Five adults from Tillamook and Blaine, Oregon, yield
     average and extreme measurements as follows: Total length, 347
     (320-370); length of tail, 125 (114-131); length of hind foot, 38
     (35-44). Tail averages 56 per cent as long as head and body.
     Length of hind foot less than basal length.

     The average differences in the external measurements are: Total
     length, 79; length of tail, 35; length of hind foot, 9.

     _Externals._--Longest facial vibrissae black, brown or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to or
     beyond apical pad of fifth digit; hairiness of foot-soles (in
     summer pledge) slightly less than shown in figure 19.

     _Color._--Upper parts, in summer, near (_n_) Argus Brown or tone 4
     of Brownish Drab of Oberthür and Dauthenay, pl. 302. Dark spot at
     each angle of mouth well developed; often fused with color of
     upper parts which sometimes covers lower lips. Chin white.
     Remainder of underparts near (14 _a´_ to 16 _c´_) Ochraceous-Buff.
     In winter, upper parts near (14) Argus Brown with smoked effect
     and Warm Buff to Naples Yellow below. Tip of tail at all times
     black. Color of underparts extends distally on posterior sides of
     forelegs over toes onto antipalmar faces of feet and usually all
     of wrists, on medial side of hind legs typically only to knee but
     sometimes to ankle. Tips of toes of hind feet almost always marked
     with color of underparts. Least width of color of underparts
     averaging in a series of 14 males from Blaine, Oregon, 23 (14-36)
     per cent of greatest width of color of upper parts. Black tip of
     tail in 8 adult males from Blaine, Oregon, averaging 59 (47-70)
     mm. long; thus longer than hind foot and averaging 37 per cent of
     length of tail-vertebrae.

     _Skull and teeth._--Male (based on 9 adults from Blaine, Tillamook
     Co., Oregon): See measurements and plates 19-21; weight, 4.4
     (3.3-5.3) grams; basilar length, 45.6 (42.4-47.7); zygomatic
     breadth more or less (usually more) than distance between condylar
     foramen and M1 or than between anterior palatine foramen and
     anterior margin of tympanic bulla; mastoid breadth more or less
     (usually more) than postpalatal length; postorbital breadth less
     (except in some instances of malformations of frontal sinuses
     which result from infestation by parasites) than length of upper
     premolars and more or less than width of basioccipital measured
     from medial margin of one foramen lacerum posterior to its
     opposite; interorbital breadth more or less than distance between
     foramen opticum and anterior margin of tympanic bulla; breadth of
     rostrum less than length of tympanic bulla; least width of palate
     more or less than length of P4; anterior margin of tympanic bulla
     as far posterior to foramen ovale as width of 3 to 4 (including
     I3) upper incisors; height of tympanic bulla more than distance
     from its anterior margin to foramen ovale; length of tympanic
     bulla more than length of lower molar and premolar tooth-row and
     more or less than orbitonasal length; anterior margin of
     masseteric fossa directly below m2.

     Female (based on 4 adults): See measurements and plates 34-36;
     weight, 2.2 (2.2-2.3) grams; basilar length, 38.1 (37.8-39.7);
     zygomatic breadth more or less (less in three of four specimens)
     than distance between condylar foramen and M1 or than between
     anterior palatine foramen and anterior margin of tympanic bulla;
     relation of postorbital breadth to other measurements in doubt
     because of malformation of frontal sinuses by parasites; least
     width of palate not less than greatest length of P4; tympanic
     bulla as far posterior to foramen ovale as width of 3-1/2 to 5-1/2
     upper incisors; height of tympanic bulla more than distance from
     its anterior margin to foramen ovale; length of tympanic bulla
     more than length of lower molar and premolar tooth-row and longer
     or shorter than rostrum.

Compared with the skull of _M. f. washingtoni_ that of each sex of
_altifrontalis_ averages slightly larger in every measurement taken,
except measurements of teeth which are approximately the same, and is
relatively deeper through the frontal region and through the braincase
as measured at the anterior margin of the basioccipital. Skulls of
females of _altifrontalis_ have a relatively broader interorbital
region. Skulls of males of _altifrontalis_ further differ in having
relatively, as well as actually, longer tympanic bullae, relatively
lesser orbitonasal length and a greater relative breadth across the
mastoids and across zygomata. Compared with _M. f. nevadensis_, the
skull of the male of _altifrontalis_ averages slightly larger and
heavier although the skulls of females are of approximately the same
size and weight. Relative to the basilar length, the skulls of both
sexes are deeper through the braincase and narrower across the
mastoids; the rostrum is broader, especially in males; the tooth-rows
are shorter and the interorbital breadth less, especially in females.
Comparison with the skull of _oregonensis_ is made in the account of
that subspecies.

_Remarks._--Until the present study was begun, animals of this race
have gone under the name _Mustela saturata_ (Merriam). The United
States National Museum has a juvenile taken, in 1858, by Wayne at
Astoria, O. T.; the Samuel N. Rhoads collection contained one specimen
taken in 1891, at Tacoma, Washington; one in the Bangs' collection was
taken at Chilliwack, British Columbia, in 1895, and the Field Museum
has one taken on the Olympic Peninsula in 1898. The best material is
that collected by Alex Walker, at Tillamook, Oregon.

Intergradation with _nevadensis_ is indicated by several specimens. The
coloration of the one adult female, no. 90, Chas. R. Conner Mus., from
Swamp Creek, Washington, has the color of the underparts extended down
the hind legs over the feet, and over the proximal third of the ventral
face of the tail as in _nevadensis_ although the other two specimens
from the same place have the color pattern of _altifrontalis_. Of the
four specimens from British Columbia referred to this subspecies, only
the specimen from Chilliwack is typical as regards color pattern. The
one from Cultus Lake has the color pattern of _nevadensis_ and might be
referred to that race almost as well as to _altifrontalis_. The two
specimens from Lihumption Park are intermediate between the two races
in tone of color. Neither has the color of the underparts extended onto
the tail or continuously over the hind feet as in _nevadensis_ but each
does have the color of the underparts less restricted and of lighter
hue than in _altifrontalis_. Only one of the specimens, no. 7848 Canad.
Nat. Mus., from Lihumption Park is adult and it has a skull which
agrees with that of _altifrontalis_ rather than _nevadensis_.

After writing the above, a good representation of the weasel population
along the eastern side of Puget Sound was made available by friends in
that area. Study of the weasels from there shows that their color is
intermediate between that of _altifrontalis_ and _nevadensis_. On the
whole, they (specimens from Bellingham, for example) resemble one
subspecies about as much as the other. In cranial characters some
specimens, in certain features, approach _nevadensis_ but most
specimens agree with _altifrontalis_ and all are more nearly like
_altifrontalis_ to which race all are referred.

The color of these animals is to me indistinguishable from that of
_washingtoni_. The color of _washingtoni_ is merely intermediate
between that of _nevadensis_ and _altifrontalis_. Nevertheless, the
race _washingtoni_ has cranial characters (long narrow skull) which set
it off from both _altifrontalis_ and _nevadensis_. This shape of skull
is not found in the specimens from along the eastern side of Puget
Sound; these animals have skulls like that of _altifrontalis_ and when
departures from this occur they are in the direction of _nevadensis_
and not _washingtoni_.

The above, then, explains why specimens which are colored like those
of _washingtoni_ are not referred to that race but instead to the race
_altifrontalis_.

Of 23 adult skulls examined, 19 have the frontal sinuses malformed as
the result of infestation by parasites.

     _Specimens examined._--Total number, 80, arranged within states by
     counties from north to south. Unless otherwise indicated specimens
     are in the United States National Museum.

     =British Columbia.= _Chilliwack_, 1[74], Lihumption Park, 4750
     ft., 2[77]; Cultus Lake, 1[77].

     =Oregon.= _Clatsop County_: Old Fort Clatsop, 1[74]; Astoria, 1.
     _Tillamook County_: Tillamook, 12 (7[14], 2[74], 2[2], 1[46]);
     Netarts, 1[46]; Blaine, 16 (13[14], 1[93], 1[76], 1[59]). _Lane
     County_: Reed, 1; Mercer, 1[46]. _Curry County_: Langlois, 1[46].

     =Washington.= _Whatcom County_: Nooksack River, 2000 ft., 14 mi. E
     Glacier, 1; Swamp Creek, 2050 ft., Nooksack River, 3[10]; Lookout,
     4800 ft., Mt. Baker, 2[10]; Bellingham, 8[25]; 5 mi. S Bellingham,
     1[49]. _Skagit County_: Rockport, 300 ft., 1. _King County_:
     Bothell, 2[94]; N Seattle 1[51]; Seattle, 1[49]; Tye, 1[51], 2 mi.
     E Skykomish, 1[51]; 7 mi. E Kent, 1[76]; Auburn, 3[94]. _Pierce
     County_: Tacoma, 1[1]. _Clallam County_: Sequim, 1[49]; Soleduc
     Riv., near [_sic._] Sappho, 1[49]; Happy Lake, 1[60]; mouth of
     Boulder Creek, Elwha River, 560 ft., Olympic Mts., 1; Hume's
     Ranch, 1000 ft., Elwha River, 1; Bogachiel Riv., 1[49]. _Mason
     County_: Lake Cushman, 2; 4 mi. N Shelton, 1[51]. _Thurston
     County_: Olympia, 2[49]; Tenino, 1[51]. _Pacific County_: 2-1/2
     mi. SE Chinook, 3[74].


=Mustela frenata oregonensis= (Merriam)

Long-tailed Weasel

Plates 19, 20, 21, 30, 34, 35 and 36

    _Putorius xanthogenys oregonensis_ Merriam, N. Amer. Fauna, 11:25,
      June 30, 1896; Bangs, Proc. New England Zoöl. Club, 1:57, June 9,
      1899.

    _Mustela xanthogenys oregonensis_, Miller, U. S. Nat. Mus. Bull.,
      79:99, December 31, 1912.

    _Mustela xanthogenys munda_, Grinnell, Univ. California Publ.
      Zoöl., 40:102, September 26, 1933 (part).

    _Mustela frenata oregonensis_, Hall, Carnegie Instit. Washington
      Publ. 473:107, November 20, 1936.

     _Type._--Male, subadult, skull and skin; no. 32019/43828, U. S.
     Nat. Mus., Biol. Surv. Coll.; Grants Pass, Rogue River Valley,
     Josephine County, Oregon; December 19, 1891; obtained by C. P.
     Streator; original no. 1404.

     The skull (plates 19-21, 30) is complete and unbroken. P3 on the
     left side is missing. Otherwise the teeth all are present although
     worn probably as a result of gnawing at the trap which captured
     the specimen. The skin, in brown, winter pelage, is fairly well
     made.

     Although the label on the skin and the label in the skull vial
     each give the sex of the specimen as female, and although Merriam
     (1896:25) regarded the specimen as a female, the present writer
     regards the specimen as a male.

     It is as large as other undoubted males and larger than any known
     female of this subspecies. The labels with the skull and skin give
     the locality as "Rogue River Valley, Oregon." The listing here of
     the more restricted locality, Grants Pass, is made on the basis of
     Merriam's (1896:25) original description of the subspecies.

     _Range._--Transition and Canadian life-zones along coast of
     northern California and southern Oregon from Humboldt County,
     California, north through Curry County, Oregon, thence inland,
     west of the Cascades, north to the Columbia River. See figures 29
     and 30 on pages 221 and 314.

     _Characters for ready recognition._--Differs from _M. f.
     altifrontalis_ in presence of frontonasal white patch, lighter
     color above (tone 2 to 3 of Raw Umber, pl. 301, rather than tone 4
     of Brownish Drab, pl. 302, Oberthür and Dauthenay), wider extent
     of light color of underparts which is extended distally beyond
     knee, and in females, longer tooth-row which amounts to more than
     38 per cent of basilar length; from _M. f. munda_ in shorter hind
     foot of males which is less than 50, and in both sexes, smaller,
     less rugose skull (see measurements and plates); from _M. f.
     saturata_ in presence of frontonasal white patch, in having color
     of underparts extended uninterruptedly over ankle onto foot; from
     _M. f. nevadensis_ in presence of frontonasal white patch, lack of
     light color of underparts on ventral face of tail, and longer
     skull, which relative to its length in males, is shallower through
     braincase; from _M. f. effera_ in presence of frontonasal white
     patch, lack of light color of underparts on ventral face of tail,
     and larger skull with basilar length averaging more than 41.7 in
     males; from _M. f. washingtoni_ in presence of frontonasal white
     patch, shorter skull in males, which in percentage of basilar
     length has, on the average, orbitonasal length amounting to less
     than 35, mastoid breadth more than 55, and zygomatic breadth more
     than 63; and in females larger skull with least width of palate
     more than length of P4, upper tooth-rows more than 38-1/2 per cent
     of basilar length, bullae larger and averaging more than 13.4
     long.

     _Description._--_Size._--Male: Five males (3 adults and 2
     subadults from Eureka, Ferndale, and Carlotta, California) yield
     average and extreme measurements as follows: Total length, 392
     (347-430); length of tail, 138 (110-160); length of hind foot, 46
     (43-50). Tail averages 54 (46-61) per cent as long as head and
     body. Length of hind foot more or less than basal length. The type
     specimen, and an adult from Goldbeach measure, respectively, as
     follows: Total length, 412, 386; length of tail, 155, 137; length
     of hind foot, 44, 46.

     Female: Three adults (2 from Fortuna and 1 from Carlotta,
     California) yield average and extreme measurements as follows:
     Total length, 367 (360-374); length of tail, 130 (123-134); length
     of hind foot, 40 (39-40). Tail averages 55 (52-57) per cent as
     long as head and body. Length of hind foot less than basal length.
     A subadult from Goldbeach, an adult from 13 mi. SW Grants Pass,
     and an adult from Medford, measure, respectively, as follows:
     Total length, 316, 344, 294; length of tail, 114, 120, 122; length
     of hind foot, 36, 40, 38.

     The average differences in external measurements of the two sexes
     in the vicinity of Carlotta, are: Total length, 25; length of
     tail, 8; length of hind foot, 6. Corresponding differences, at
     Goldbeach, are: 70, 23, 10. Probably the females at Fortuna
     reflect the large size of _munda_ more than do the males at
     Carlotta and the differences between the measurements of the two
     sexes probably, therefore, are actually more than are indicated by
     the figures above.

     _Externals._--Longest facial vibrissae black, brown or white
     (often all three colors in same specimen) and extending beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles, in summer
     pelage, as shown in figure 20.

     _Color._--Upper parts, in summer, near (16 _l_) Brussels Brown or
     tone 2 of Raw Umber of Oberthür and Dauthenay, pl. 301, to
     slightly darker than tone 3 of same plate. Darker on nose and top
     of head, usually with frontonasal white patch but lacking white
     bar in front of each ear, except in the type and 2 specimens from
     Salem. Chin, lower lips, angle of mouth, and usually posterior
     seventh of upper lip white. Remainder of underparts Pale
     Orange-Yellow. In winter usually lighter above with underparts
     Warm Buff to Straw Yellow. Tip of tail at all times black. Color
     of underparts extends distally on posterior sides of forelegs over
     toes onto antipalmar faces of feet and wrists, on medial side of
     hind leg, typically over ankle in extremely narrow line which
     widens out over distal phalanges of antiplantar faces of toes but
     sometimes interrupted at ankle. Least width of color of underparts
     averaging, in twenty available specimens, 39 (27-54) per cent of
     greatest width of color of upper parts. Black tip of tail in five
     adults averaging 50 (43-60) mm. long; thus averaging longer than
     hind foot and 33 per cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on 4 adults and subadults from
     Eureka, Requa, Goldbeach, and Grant Pass): See measurements and
     plates 19-21, 30. As described in _Mustela frenata nevadensis_
     except that: Weight, 3.5 (3.5-4.1) grams; basilar length, 42.9
     (41.8-44.0); least width of palate more or less than medial length
     of P4.

     Female (based on 2 adults, one from Carlotta and one from 13 mi.
     SW Grants Pass): See measurements and plates 34-36. As described
     in _Mustela frenata nevadensis_ except that: Weight, 2.4 (2.2-2.6)
     grams; basilar length, 37.7 and 39.5; zygomatic breadth less than
     distance between condylar foramen and M1 and less than distance
     between anterior palatine foramen and anterior margin of tympanic
     bulla. See under "_Remarks_" for additional data on variation in
     size of skulls of females.

     The skulls of the female averages 31 per cent lighter than that of
     the average male.

Because there is much geographic variation between specimens here
referred to _oregonensis_, the person who is guided by the present
account should keep in mind that results, here reported, of comparisons
of the skull with those of other races, were obtained by employing
specimens of _oregonensis_ from Carlotta and Eureka, California. These
specimens from California are judged to have more of the characters of
the subspecies _munda_ than do specimens of _oregonensis_ from more
northern localities.

Compared with that of _M. f. washingtoni_ the skull of the male is
shorter, especially in the preorbital region and is relatively broader
across the mastoidal processes and zygomatic arches. The skull of the
female is longer in the preorbital region, has a less cylindrical
braincase and differs less from the male skull than is the case in _M.
f. washingtoni_. Compared with _M. f. effera_, the skull of the male is
smaller in every part measured and relative to the basilar length is
broader across the mastoids and has relatively shorter tympanic bullae.
From _M. f. nevadensis_ the skull of the male differs in the same way
except that size is about the same. The skull of the female
_oregonensis_ is more heavily ridged and is relatively broader across
the mastoids than that of _effera_. From _M. f. saturata_,
_oregonensis_ is not surely known to differ in cranial characters. From
_M. f. munda_, _oregonensis_ differs in having the skull of both sexes
smaller, and on the average, in all parts measured, has a less marked
postorbital constriction, relatively narrower interorbital region and
relatively more expanded zygomata. From _M. f. altifrontalis_, males of
_oregonensis_ differ on the average, in having larger teeth, and
relative to the basilar length, a greater mastoid breadth and a
shallower braincase as measured at the anterior margin of the
basioccipital. Females of _oregonensis_ differ in larger average size
of skull, except for breadth of rostrum and interorbital breadth which,
therefore, are relatively less in _oregonensis_, as also is the
relative depth of the skull measured at the posterior borders of the
upper molars and at the anterior margin of the basioccipital. However,
skulls of females of _oregonensis_ have relatively longer tooth-rows
and are relatively broader across the zygomata and mastoidal processes.

_Remarks._--In 1896, Merriam named _oregonensis_ as a subspecies of the
California bridled weasel on the basis of a single specimen taken by
Clark P. Streator. Three additional specimens were acquired in later
years, by workers of Dr. Merriam's bureau, from near the type locality
and specimens from farther north in Oregon have been accumulated at the
University of Oregon. The most satisfactory material is that saved from
Humboldt County by the late H. E. Wilder, which, when brought together,
is adequate to give some idea of the range of variation that can be
expected in a given population.

Of two specimens from Goldbeach, one shows approach to _altifrontalis_
in that the color of the underparts stops at the ankle, and in one, the
angle of the mouth is dark colored. Specimens from Eugene and vicinity
lack the white facial markings, and in this feature approach the
adjoining _washingtoni-effera-nevadensis_ stock. A specimen from 6
miles south of Medford shows approach to _saturata_ in the
interruption, on the ankle and lower tibial region, of the color of the
underparts. One adult female, no. 1413, Univ. Oregon, from the Rogue
River Valley, 13 miles southwest of Grants Pass, stands out
prominently, among the other specimens from extreme southern Oregon and
northwestern California, by reason of the near (18) Apricot Yellow
color of the underparts, but this same color occurs in specimens from
the more northerly localities of Buchanan, Eugene, Vida Fish Hatchery,
and McKenzie Bridge, as well as in no. 2178, Univ. Oregon, from Cresent
Lake. The last mentioned specimen is here referred to _nevadensis_.

Two females referred to _oregonensis_ from southern Oregon differ so
greatly in size of skull that they challenge one's imagination in any
attempt to provide an explanation for so wide a range of variation in
one subspecies. One of these, no. 244520, U. S. Nat. Mus., is an adult
female from Medford. The other, no. 224034, U. S. Nat. Mus., is a
subadult female (though labeled male) from 43 miles northeast of Grants
Pass. The skull of the adult from Medford has a basilar length of 41.5,
upper tooth-rows, 16.1 in length, and a weight of 2.75 grams, whereas
corresponding figures for the subadult are only 33.8, 12.9, and 1.4.
Two other adult females are intermediate in size: No. 1413, Univ.
Oregon, from 13 miles southwest of Grants Pass, Oregon, approaches the
specimen from Medford in size, and the second specimen, no. 34325, Mus.
Vert. Zoöl., from Carlotta, California, is smaller.

Not only is there a difference in length between the skulls of the two
extremes of the females but this difference extends to all other
dimensions of their skulls, and is most pronounced in the preorbital
region. The differences in breadth of the braincase and other parts of
the skull are relatively less than the differences in length.
Differences of the same nature, although of lesser degree than found in
the females, are to be seen in two males. The skull of an adult no.
51590, Mus. Vert. Zoöl., from 6 miles south of Medford, has a basilar
length of 46.4, upper tooth-rows, 17.6 mm. long, and a weight of 4.0
grams, whereas corresponding figures for the subadult type specimen
from Grants Pass, are only 43.0, 16.2, and 3.3.

The wide range of variation in size of skull of both sexes, together
with the considerable variation in color pattern of the specimens here
referred to _oregonensis_ raises the suspicion that we are using the
name in a composite sense; nevertheless, to recognize more than one
subspecies with the material now available would be unwise.

A subadult female, of abnormal color, no. 47149, Mus. Vert. Zoöl.,
taken by Mr. H. E. Wilder at Carlotta, California, on December 20,
1930, in a region where weasels do not turn white in winter, is white,
except for the black tip of the tail, but has a suffusion of orange.
This specimen, discussed at greater length on page 43, is instructive
in that it suggests that there are separate determiners for the brown
and red elements of the pelage. It is interesting also as suggesting
how natural selection may tend to eliminate from the population a
conspicuous color-variation of this kind. At any rate, Mr. Wilder (Ms.)
states: "This specimen was picked up in a field, where it evidently had
been dropped by a hawk or an owl." The braincase of the skull is
crushed in three places as though by a raptor's beak. None of the
several other weasels, all normally colored, saved by Mr. Wilder from
this general locality gives evidence of having fallen a victim to a
raptor.

Only 2 skulls of the 12 adults and subadults examined show malformation
of the frontal sinuses such as results from the presence of parasites.

     _Specimens examined._--Total number, 29, arranged within states
     from north to south by counties. Unless otherwise indicated
     specimens are in the collection of the United States National
     Museum.

     =California.= _Del Norte County_: Requa, 1[8]. _Humholdt County_:
     Eureka, 2 (1[74], 1[75]); Ferndale, 1[74]; Fortuna, 2[63];
     Carlotta, 6 (3[74], 3[59]); 12 mi. E Bridgeville, 1[59]; 2 mi. W
     Bridgeville, 1[59].

     =Oregon.= _Washington County_: Forest Grove, 1. _Marion County_:
     Salem, 2. _Benton County_: Buchanan, 1. _Lane County_: McKenzie
     Bridge, 1[101]; Vida Fish Hatchery, 1[101]; Eugene, 1[101].
     _Douglas County_: Anchor, 1. _Curry County_: Gold Beach, 2[60].
     _Josephine County_: Rogue River Valley (Grants Pass), 1; 13 mi. SW
     Grants Pass, 1[101]. _Jackson County_: Medford, 2; 6 mi. S
     Medford, 1[74].


=Mustela frenata munda= (Bangs)

Long-tailed Weasel

Plates 1, 19, 20, 21, 22, 23, 30, 34, 35, 36 and 40

    _Putorius xanthogenys mundus_ Bangs, Proc. New England Zoöl. Club,
      1:56, June 9, 1899; Stephens, California mammals, p. 247, 1906.

    _Mustela frenata_, Audubon and Bachman, Journ. Acad. Nat. Sci.
      Philadelphia, 8 (Pt. 2):291, 1842 (North California about 40°
      latitude).

    _Mustela xanthogenys munda_, Miller, U. S. Nat. Mus. Bull., 79:99,
      December 31, 1912.

    _Mustela frenata munda_, Hall, Carnegie Instit. Washington Publ.
      473:107, November 20, 1936.

     _Type._--Male, adult, skull, os penis and skin; no. 5459,
     collection of E. A. and O. Bangs, but now in collection of Mus.
     Comp. Zoöl.; Point Reyes, Marin County, California; June 19,
     1896; obtained by C. A. Allen; original no. 931. (See comments
     under "Remarks," below, on places in California to which the name
     Point Reyes has been applied.)

     The skull (pls. 19-21, 30) is complete and unbroken. I1 on each
     side and right I2 are broken away; p2 and p3 on each side have
     been aborted and the only alveoli remaining are two for the right
     p3. Otherwise all teeth are present and entire. The skin is fairly
     well made and in good condition.

     Cranially, the type is a "runt"; its small size and the
     circumstance that the tympanic bulla is longer than the lower
     molar and premolar tooth-row and longer than the rostrum are
     features which differentiate the type from any other specimen seen
     of this race.

     _Range._--Sea level to at least 6,000 feet (South Yolla Bolly
     Mountain, Trinity County, California); Upper Sonoran and
     Transition life-zones of the coast and Coast Range of northwestern
     California from the Golden Gate northward into southern Humboldt
     and Trinity counties. See figures 29 and 30 on pages 221 and 314.

     _Characters for ready recognition._--Differs from _M. f.
     oregonensis_ in longer hind foot of males which is more than 50
     mm., and in both sexes, larger, more prominently ridged skull (see
     measurements and plates); from _M. f. saturata_ by presence of
     nasofrontal white spot, larger and relatively shallower skull of
     males and larger skull of female; from _M. f. nevadensis_ by
     presence of well-developed, white, facial markings; absence of
     color of underparts on ventral face of proximal third of tail; and
     hind foot of males more than 50; from _M. f. xanthogenys_ by near
     (_l_) Sudan Brown to near (_l_) Antique Brown rather than
     Buckthorn Brown colors of upper parts and greater size, and in
     adult male basilar length more than 45 and hind foot more than 47;
     from _M. f. nigriauris_ by having inside of ears same color as
     back rather than much darker than back.

     _Description._--_Size._--Male: Three adults and two young from
     Point Arena and Gualala, Mendocino County, yield average and
     extreme measurements as follows: Total length, 447 (434-470);
     length of tail, 167 (150-185); length of hind foot, 53 (50-60).
     Corresponding measurements of three adults from 5 and 6 miles west
     of Inverness, Marin County, are: 430 (420-440), 154 (141-160), 48
     (48-49). Corresponding measurements of four individuals (3 adults
     and 1 young of large size) from South Yolla Bolly Mountain,
     Trinity County, are: 383 (374-400), 134 (130-138); 44 (43-44). The
     tail averages 60 per cent as long as the head and body in the
     series from Point Arena, 56 per cent in the series from Point
     Reyes, and 53 per cent in the series from South Yolla Bolly
     Mountain. In every specimen except two, length of hind foot less
     than basal length. The two exceptions are no. 19720, M.V.Z., male
     adult from Point Arena in which the hind foot is recorded as 60
     (probably an error in measurement), and no. 19721, M.V.Z., from
     the same place, in which the skull has not yet attained its full
     growth.

     Female: One adult from Point Arena measures as follows: Total
     length, 383; length of tail, 134; length of hind foot, 43.
     Corresponding measurements of an adult from seven miles north of
     Laytonville, Mendocino County, are: 336, 121, 33 (= 36 on dried
     skin). Corresponding measurements of an adult from South Yolla
     Bolly Mountain, Trinity County, are, 326, 113, 37. In these three
     specimens, the tail is, in the order given, 54, 56, and 53 per
     cent as long as the head and body. Length of hind foot more than
     basal length.

     Differences in external measurements of the two sexes as indicated
     by the five males and one female from Point Arena, are: Total
     length, 64; length of tail, 33; length of hind foot, 10. Weights
     of 2 adult males are 265 and 221 grams and of one adult female 155
     grams.

     _Externals._--As described in _Mustela frenata nigriauris_.

     _Color._--Spot between eyes, narrow band or spot confluent with
     color of underparts on each side of head anterior to each ear,
     chin, lower lips, and rarely posterior third or less of each upper
     lip white; dark spot posterior to each angle of mouth uniformly
     present and of large size; tip of tail black; remainder of upper
     parts near (14 _l_) Sudan Brown and tone 4 of Raw Umber of
     Oberthür and Dauthenay, pl. 301; occasionally, slightly darker
     brown on forehead, nose, and about eyes. Underparts near (_a_ to
     _c_) Ochraceous-Buff and sometimes Orange-Buff. Color of
     underparts extends distally on posterior sides of forelegs over
     toes onto antipalmar faces of feet and wrists, on medial sides of
     hind limbs over antiplantar faces of toes. Least width of color of
     underparts averaging, in a series of 5 males from Mendocino
     County, 57 (46-67) per cent of greatest width of color of upper
     parts; 38 (35-40) in 3 males from Point Reyes, Marin County. Black
     tip of tail in Mendocino County series averaging 53 (46-60) mm.,
     which is same length as hind foot and 32 per cent of length of
     tail. In Point Reyes males, black tip of tail averages 44 (34-52)
     mm., which is less than length of hind foot and 45 per cent as
     long as tail-vertebrae.

     Several specimens of the smaller, inland variant (see under
     "_Remarks_") are near (_l_) Antique Brown rather than near (14
     _l_) Sudan Brown above and hence do not differ in this respect
     from _nigriauris_.

     _Skull and teeth._--Male (based on 3 adults from Mendocino
     County): See measurements and plates 19-23, 30. As described in
     _Mustela frenata nigriauris_ except that: Weight, 6.0 (5.4-6.3)
     grams; basilar length, 47.6 (46.5-48.2); length of tympanic bulla
     more than length of lower molar and premolar tooth-row.

     Female (based on no. 19723, M.V.Z., from Point Arena): See
     measurements and plates 34-36, 40. As described in _M. f.
     nigriauris_ except that: Weight, 3.0 grams; basilar length, 42.3.

     The skull of the female is 50 per cent lighter than that of the
     average male.

Compared with the skull of the male of _nevadensis_ that of _munda_
averages larger in every part measured and specimens from Point Arena
are nearly as heavy again, have relatively more expanded zygomata and
mastoid processes but are relatively narrower anteriorly as shown by
the breadth of the rostrum, interorbital breadth and postorbital
breadth. Also the braincase is less inflated anteriorly, the tympanic
bullae are lower and the skull is more angular. Females show the same
differences although in different degree. Compared with the skull of
the male of _M. f. nigriauris_, that of _munda_ from Point Arena
averages larger in every part measured except for the length of the
upper tooth-rows. Relative to the basilar length, the skull of _munda_
averages broader across the mastoids and across the zygomata, is deeper
through the braincase at the anterior end of the basioccipital, and
has a greater development of the lambdoidal crest.

_Remarks._--The skin and part skull, no. 536/1849, U. S. Nat. Mus.,
taken by Lieutenant W. P. Trowbridge at San Pablo Bay, is the first
specimen known to have been saved of this subspecies. Since 1899 when
O. Bangs diagnosed _munda_ as of small size, the weasel of the humid
costal belt north of San Francisco Bay has been regarded as smaller
than bridled weasels from farther south in the State. Actually,
however, the weasel of the humid costal belt shares with _M. f.
pulchra_ the distinction of being one of the two largest weasels in
California.

_M. f. munda_ may be a composite subspecies, for the variation in
facial markings, in coloration otherwise, in external measurements and
in size and shape of skull is great. At one time in the course of the
present study, manuscript accounts of two subspecies were prepared for
the animals now all called _munda_ and there is still much
justification for recognizing two subspecies, one, along the coast
proper, the larger, darker-colored animal with reduced white facial
markings and large, wide, heavily ridged skull from Point Arena, and 6
miles south of Laytonville, Mendocino County, along with the specimens
from 5 and 6 miles west of Inverness, Marin County, and the other, an
inland race, which is a smaller, lighter-colored animal with more
extensive white facial markings and a smaller, narrower, skull, known
by specimens from Point Reyes [station?], Nicasio, 15 mi. north of San
Rafael, Freestone, Vallejo, and Mount Sanhedrin. The differences
between these two lots of specimens are of great degree. However, a
female from Fort Bragg proves to be no larger than three females
labeled as from Point Reyes. Also, a male from 2 miles south and one
mile east of Stewarts Point on the coast has a skull no larger than the
animal from Vallejo, whereas the skin alone of an adult female from 3
miles south of Stewarts Point is large and agrees with the specimens
from Point Arena. Consequently, no logical ranges can be worked out for
the two variants with the material now available.

Finally, the type specimen of _munda_ is a "runt," smaller than any
other male seen. This specimen, purchased by E. A. and O. Bangs from C.
A. Allen, who collected and sold specimens widely, was labeled as from
Point Reyes. So far as this place-name is concerned, it might refer to:
(1) The point of land by that name which projects out into the Pacific
Ocean, (2) an abandoned ranch house bearing that name at the head of
Drakes Bay, 6 miles north and 3-3/4 miles east of the actual point, or
(3) the railway station by the same name at the head of Tomales Bay,
12 miles east and 4-3/4 miles north of the actual point. Allen,
himself, lived near San Geronimo (then Nicasio) about nine miles
southeast of the Point Reyes railway station. All these places are in
Marin County, but differ markedly as regards climate and flora. The
first two are treeless, windswept and have much fog, whereas Point
Reyes Station is more often sunny, and is situated in a shallow valley,
inland, where the open grass-covered west-facing slopes meet the
east-facing wooded ones. From which one of these three places the type
specimen came, I do not know. The same may be said of the three female
specimens labeled Point Reyes; two of these are in the United States
National Museum and one in the Field Museum.

The specimens in the Museum of Vertebrate Zoölogy from 5 and 6 miles
west of Inverness and those from near the same place in the collection
of John Cushing come from within a couple of miles or less of the Point
Reyes represented by the abandoned ranch house. These specimens, as
remarked above, agree with those from Point Arena in large size,
reduced facial markings and wide skull. These are points of difference
from the smaller variant suspected of being a recognizable subspecies.
It is the smaller variant which the type specimen approaches in size,
and with which it agrees in relatively well-developed white facial
markings. This suggests that the type specimen came from Point Reyes
Station rather than from either of the two other places bearing the
name "Point Reyes," from one of which, as just stated, the variant of
large size is known. The three females labeled "Point Reyes" also have
well-developed white facial markings and are of lesser size than the
female of similar age from Point Arena, Mendocino County. The
presumption is that these three females also came from Point Reyes
Station.

The smaller, inland variant seems to agree in size, cranial characters,
and coloration with _M. f. nigriauris_ to the southward of San
Francisco Bay, but lacks the black on the head which characterizes
_nigriauris_. The larger variant, on which the description here used
for _munda_ is based, comprises animals which differ from _nigriauris_
in larger size, darker color, reduced white facial markings, and
larger, relatively wider skull. Both of the variants mentioned above
are sharply distinct from _nigriauris_ on the basis of coloration of
the inside of the ear which is blackish in nigriauris like the dark
facial markings, and in _munda_ is colored like the back. _M. f. munda_
lacks the dark facial markings; an occasional specimen has at most, a
trace of the markings but this does not extend back so far as the ears.
This difference, blackish versus non-blackish face, persists eastward
of San Francisco Bay to at least as far as the Carquinez Straits, where
a specimen of _munda_ is available from 4 miles north of Vallejo and
one of _nigriauris_ from Glen Frazer Station on the south shore
opposite Vallejo.

[Illustration: FIG. 30. Map showing the geographic distribution of
subspecies of _Mustela frenata_ in California]

Intergradation with _M. f. nevadensis_ and possibly with _M. f.
saturata_ is indicated by specimens from South Yolla Bolly Mountain,
Trinity County. In them the external measurements and measurements of
the skull are intermediate. Also the white frontal spot is much reduced
in size. The white bars in front of the ears are absent in three
specimens, and weakly developed in the other two. The relative
proportions of the skulls as a whole are nearer those of _nevadensis_
or _saturata_ than _munda_. The skull of one of the three adult males
and the skull of the adult female suggests _M. f. oregonensis_ in
certain features; for example, the dorsal outline of the skull in
longitudinal axis is slightly convex as it is in _oregonensis_.

None of the specimens shows malformation of the frontal sinuses such as
results from infestation by parasites.

     _Specimens examined._--Total number, 37, arranged by counties from
     north to south. Unless otherwise indicated specimens are in the
     Museum of Vertebrate Zoölogy.

     =California.= _Trinity County_: S. Yolla Bolly Mt., 3[91]; 1/2 mi.
     S S. Yolla Bolly Mt., 1. _Tehama County_: 2 mi. S S. Yolla Bolly
     Mt., 1. _Mendocino County_: 6 mi. N Laytonville, 1; Mt. Sanhedrin,
     1[87]; Ft. Bragg, 1; Gualala, 1; Point Arena, 5. _Sonoma County_:
     2 mi. S and 1 mi. E Stewarts Point, 1; 3 mi. S Stewarts Point P.
     O., 1; Freestone, 1. _Napa County_: 6 mi. SSW, Napa, 1; 4 mi. N
     Vallejo, 1. County in question: San Pablo Bay, 1[91]. _Marin
     County_: 6 mi. W Inverness, 2; 5 mi. W Inverness, 2(1[28]); Point
     Reyes, 4 (2[91] 1[60], 1[75]); Nicasio, 2 (1[60], 1[75]); Kehoes
     Ranch, Pierce Point, 1[28]; Drakes Bay, 1[28]; Tomales Point,
     about 1/2 mi. SW White Gulch, 1; Point Reyes School, 3-3/4 mi. W
     Inverness, 1; 15 mi. (by road) N San Rafael, 1[52]; Hurley Ranch,
     2 mi. W Tomales, 1. No locality more definite than California,
     1[7].


=Mustela frenata xanthogenys= Gray

Long-tailed Weasel

Plates 21, 22, 23, 28, 30, 34, 35 and 36

    _Mustela xanthogenys_ Gray, Ann. and Mag. Nat. Hist., 11:118, 1843.

    _Putorius (Gale) brasiliensis frenatus_, Coues, Fur-bearing
      animals, p. 142, 1877 (part).

    _Putorius xanthogenys_, Merriam, N. Amer. Fauna, 11:25, June 30,
      1896; Bangs, Proc. New England Zoöl. Club, 1:56, June 9, 1899.

    _Mustela xanthogenys xanthogenys_, Miller, U. S. Nat. Mus. Bull.,
      79:99, December 31, 1912.

    _Mustela frenata xanthogenys_, Hall, Carnegie Instit. Washington
      Publ. 473:107, November 20, 1936.

     _Type._--Male, adult, skull and skin; skull no. 197a-43.6.4.55,
     skin no. 234a-42.11.21.4, British Museum (Nat. Hist.); from the
     bank of Sacramento River below mouth of Feather River, or from
     north shore of San Francisco Bay, California; taken in "1837 or
     1838"; presented by Captain Edward Belcher.

     The skull (plate 28) lacks the occiput, the right mandible
     posterior to m1, and the right pterygoid; the right zygomatic arch
     is fractured. The teeth are not greatly worn. The skin was
     originally mounted for exhibition (R. I. Pocock in Litt.) but in
     1937 when I saw the skin, it was prepared as a conventional study
     skin. The skin is in fairly good condition; some hair is missing
     on the hind quarters and the skin of the tail is torn at one
     place.

     _Range._--Altitudinally, less than 600 feet (Fair Oaks); Lower
     Sonoran and Upper Sonoran life-zones of all but southern end of
     the San Joaquin Valley, and probably Sacramento Valley,
     California. See figures 29 and 30 on pages 221 and 314.

     _Characters for ready recognition._--Differs from _M. f.
     nevadensis_ by presence of light facial markings and Buckthorn
     Brown rather than near (14_n_ to _l_) Brussels Brown color of
     upper parts; from _M. f. munda_ by Buckthorn Brown rather than
     near (_l_) Sudan Brown, or near (_l_) Antique Brown color of upper
     parts and lesser size, in adult males basilar length less than 45
     and hind foot less than 47; from _M. f. nigriauris_ by lighter
     color in same way as from _munda_ and also by having inside of
     ears same color as back rather than much darker than back; from
     _M. f. pulchra_ in hind foot of males less than 46 and narrower
     skull, in males having breadth of rostrum less than 13.9 and
     mastoid breadth less than 26.0, see comparison of skulls in the
     account of _pulchra_.

     _Description._--_Size._--Male: Three adults, from Fresno, Selma
     and Los Banos, measure, respectively as follows: Total length,
     425, 417, 450; length of tail, 152, 154, 180; length of hind
     foot,--, 43, 44. Tail averages 61 per cent as long as head and
     body. Length of hind foot less than basal length.

     Female: Adults from Selma, Los Banos, and 4 mi. SW Turlock,
     measure respectively as follows: Total length, 357, 365, 395;
     length of tail, 133, 132, 145; length of hind foot, 40, 38, 41.
     Tail averages 58 per cent as long as head and body. Length of hind
     foot less than basal length.

     The average differences in external measurements between the two
     sexes, as represented by these six specimens, are: Total length,
     65; length of tail, 25; length of hind foot, 3.5. One adult male
     weighs 274 grams and 2 adult females 182 and 214 grams.

     _Externals._--As described in _Mustela frenata nigriauris_.

     _Color._--Spot between eyes, band confluent with color of
     underparts on each side of head extending anterodorsally anterior
     to each ear, and posterior half to third of each upper lip white,
     or whitish tinged with some shade of yellowish; chin and lower lip
     white; dark spot posterior to each angle of mouth of varying size
     but uniformly present; tip of tail black; remainder of upper parts
     Buckthorn Brown of Ridgway or a trifle browner than tone 4 of
     Brown Pink of Oberthür and Dauthenay, pl. 297. Upper parts of
     uniform color except for slight darkening of head-markings
     anterior to ears. Underparts Ochraceous-Buff to Warm Buff. Color
     of underparts extends distally on posterior sides of forelegs over
     toes onto antipalmar faces of feet and wrists, on medial sides of
     hind limbs over antiplantar faces of toes and sometimes tarsal
     region. Least width of color of underparts averaging, in 9
     specimens from Fresno, Selma and Los Banos, 54 (32-74) per cent of
     greatest width of color of upper parts. Black tip of tail in three
     males (one subadult and 3 adults) averages 55 (50-60) mm. long.
     Thus longer than hind foot and averaging 34 per cent of length of
     tail-vertebrae.

     _Skull and teeth._--Male (based on 2 adults from Fresno and one
     from Selma): See measurements and plates 21-23, 30. As described
     in _M. f. nigriauris_ except that: Weight 3.8 grams; basilar
     length, 43.7 (43.4-43.9); least width of palate more or less than
     lateral length of P4; length of tympanic bulla more than length of
     lower molar and premolar tooth-rows.

     Female (no. 2626 W. E. Snyder, from Selma): See measurements and
     plates 34-36. As described in _M. f. nigriauris_ except that:
     Weight, 2.5 grams; basilar length, 39.4.

     The skull of the female is 34 per cent lighter than the average
     for the three males.

Compared with skulls of _nevadensis_ from the Sierra Nevada, those of
the two adult males from Fresno differ as follows: M1 wider
(transversely); tympanic bullae narrower; preorbital part of skull
smaller. Comparison with _pulchra_ is made in the account of that
subspecies. Compared with skulls of adult males of _nigriauris_, from
Santa Clara County, the two skulls from Fresno are generally smaller
and in basilar length, length of tooth-rows and measurements of the
teeth fall below the minimum for _nigriauris_. Relative proportions of
the skulls are approximately the same. Comparison with _munda_ reveals
essentially the same differences as does comparison with _nigriauris_
except that the difference in size is greater.

_Remarks._--The name _Mustela xanthogenys_ Gray was long applied to all
the weasels of the interior valleys of California and of the coast of
that state south of San Francisco Bay. Gray, when he named the species
and when referring to it in later accounts, never defined the locality
whence the specimen came more definitely than "California." In 1896,
Merriam (1896:25) gave the type locality as "Southern California,
probably vicinity of San Diego" and later writers have not contradicted
him. The type specimen was obtained in the course of the voyage of the
British ship Sulphur, under command of Sir Edward Belcher. Examination
of Belcher's (1843, vol. 1, p. 129) narrative of the voyage indicates
the following places in California at which the specimen of weasel,
described by Gray, could have been obtained: Fort Ross, Bodega,
vicinity of San Francisco Bay and up Sacramento River to the mouth of
the Feather River, Monterey, Santa Barbara, Buenaventura, San Pedro,
San Juan, and San Diego.

Reginald I. Pocock has kindly compared the type specimen in the British
Museum with several specimens sent for that purpose. In the first
place, comparison of skulls shows that the type specimen is a member of
one of the races north of San Diego. In the second place, comparison of
skins shows that the inside of the ears are not blackish but similar in
color to the back. In fact, Pocock writes under date of February 12,
1929, regarding the type specimen, that "It is practically uniformly
colored from the snout to the base of the tail, there being scarcely a
trace of the darkening of the head, or muzzle, observable in your
specimens [those sent for comparison]." This character of coloration of
the ear excludes all the weasels of the Coast region of California from
San Francisco Bay southward, namely, _M. f. latirostra_ and _M. f.
nigriauris_. My own examination of this type specimen at a date later
than that on which Pocock compared it satisfies me as to the accuracy
of his statement above.

Accordingly, the name _xanthogenys_ would seem to apply to one of the
two subspecies here called _munda_ and _xanthogenys_. Perusal of
Belcher's narrative of the voyage (_loc. cit._) shows that little, if
any, opportunity was afforded to obtain vertebrate specimens at Fort
Ross or Bodega, both localities within the range of the subspecies here
called _munda_. Furthermore, the type specimen is smaller than
individuals of _munda_ from 5 to 6 miles west of Inverness and from
Point Arena with which the animals from Fort Ross and Bodega would be
expected to agree in size. Weasels from along the north shore of San
Francisco Bay are smaller than those on the coast north of the bay.
Possibly the type specimen of _xanthogenys_ came from the north side of
San Francisco Bay but probably it came from the bank of the Sacramento
River and almost certainly not farther up stream from San Francisco Bay
than the junction of the Sacramento and Feather rivers. The statement
of Belcher (1843, vol. 1, p. 129), regarding the trip up the Sacramento
River as far as Point Victoria, lat. 38°46´47" north, and return to
San Francisco Bay, that "Cuyote or jackal--fox, racoon, land otter,
weasel, and squirrel were obtained" lends strong probability to the
idea that this type specimen was taken along the Sacramento River,
possibly in the vicinity of the existing city of Sacramento.
Unfortunately no specimens are available from the Sacramento Valley. If
some were available, a comparison of them and specimens of _munda_ from
along the north side of San Francisco Bay and Carquinez Straits with
the type specimen of _xanthogenys_ should determine the correct
application of the name. For the present it seems best to retain the
name _munda_ and apply the name _xanthogenys_ to the weasels inhabiting
the northern part of the San Joaquin Valley and presumably the southern
part of the Sacramento Valley.

Efforts to obtain specimens of weasels from the Sacramento Valley have
been in vain. A juvenal specimen taken five miles south of Fair Oaks,
Sacramento County, by Mr. John Fitzgerald, Jr., in December, 1927, was
examined at his home and found to agree in coloration with specimens
from farther south. Geographically, this specimen probably is more
nearly a topotype than any other examined.

Most of the specimens examined are immature and adequate adult cranial
material has not been seen. Two adults, one of each sex, from Los Banos
have skulls of large size which agree with those of _nigriauris_. The
same is true of one adult and one young female from 4 miles southwest
of Turlock, which, unlike the animals from Los Banos, show a darkening
of the head extending in reduced degree even to the inside of the ears,
as in _nigriauris_. The slightly darker than average (for
_xanthogenys_) color on the back may indicate intergradation with
_nevadensis_. Intergradation with _M. f. nevadensis_ is shown by
specimens, from the southern part of the Sierra Nevada, mentioned in
the account of _nevadensis_.

None of the skulls shows malformation of the frontal sinuses such as
result from infestation by parasites.

     _Specimens examined._--Total number 30, arranged by counties from
     north to south.

     =California.= _Sacramento County_: Bank of Sacramento River, 1[7];
     5 mi. S Fair Oaks, 1[29]. _San Joaquin County_: 4 mi. W Stockton,
     1[74]. _Merced County_: Tegner School, 4 mi. SW Turlock, 2; Los
     Banos, 4 (2[74], 1[91] 1[87]). _Fresno County_: Mendota, 1[74];
     Biola, 1[30]; Clovis, 1[55]; Fresno, 5 (1[74], 1[91], 2[55],
     1[1]); 5 mi. W Fresno, 1[14]; Selma, 3 (2[50], 1[104]); 4 mi. NW
     Sanger, 1[55]; 5 mi. S Selma, 1[62]. _Tulare County_: Monson,
     1[74]; 1-1/2 mi. N Goshen, 1[74]; Milo, 1[91]; 2 mi. N Tipton,
     1[74]; Poplar, 2[53]. No locality more definite than California,
     1[4].


=Mustela frenata nigriauris= Hall

Long-tailed Weasel

Plates 22, 23, 24, 34, 35, 36 and 41

    _Mustela frenata nigriauris_ Hall, Carnegie Instit. Washington
      Publ. 473:95, November 20, 1936.

    _Putorius xanthogenys_, Baird, Mamm. N. Amer., 1858, p. 176 (part).

    _Mustela xanthogenys_ Gray, Ann. and Mag. Nat. Hist., 14(ser.
      4):375, 1874 (part?).

    _Putorius (Gale) brasiliensis frenatus_, Coues, Fur-bearing
      animals, p. 142, 1877 (part).

    _Putorius xanthogenys xanthogenys_, Grinnel, Proc. California Acad.
      Sciences, fourth series, 3:292, August 28, 1913.

    _Mustela xanthogenys xanthogenys_, Miller, U. S. Nat. Mus. Bull.,
      79:99, December 31, 1912; Grinnell, Univ. California Publ. Zoöl.,
      40:102, September 26, 1933.

     _Type._--Male, adult, skeleton and skin; no. 32820, Mus. Vert.
     Zoöl.; Half Moon Bay, San Mateo County, California; received at
     Museum of Vertebrate Zoölogy, May 4, 1922, through A. L.
     Hagedoorn, after having been in captivity a few days where death
     occurred owing to injuries received in trap; original no. 1590.

     The skull has each of the zygomatic arches and the anterior end of
     the nasals broken through. The only part missing is the central
     two millimeters of the left zygomatic arch. The teeth all are
     present and entire. The skeleton appears to be complete except for
     the bones of the feet, which are preserved within the skin. The
     skin is well made and in good condition.

     _Range._--Altitudinally, sea level to more than 4000 feet; Sonoran
     and Transition life-zones of Coast Range and coast of California
     from San Francisco Bay south to Point Conception, Santa Barbara
     County, California. See figures 29 and 30 on pages 221 and 314.

     _Characters for ready recognition._--Differs from _M. f. munda_,
     _xanthogenys_, and _pulchra_ by having inside of ears darker than
     back rather than same color as back, and from _xanthogenys_ and
     _pulchra_ in near (_l_) Antique Brown color of upper parts rather
     than Buckthorn Brown or near (16 _j_) Buckthorn Brown to near
     (_h_) Yellow Ocher respectively; from _M. f. latirostra_ by
     postorbital breadth, of adult males and females, less, rather than
     more, than width of basioccipital measured from medial margin of
     one foramen lacerum posterior to its opposite.

     _Description._--_Size._--Male: Five adults from Palo Alto, Santa
     Clara County, yield average and extreme measurements as follows:
     Total length, 447 (412-465); length of tail, 167 (147-175); length
     of hind foot, 46 (45-47). Corresponding measurements of four
     adults from San Francisco are: 412 (394-435); 153 (145-160); 43.5
     (41-46). Corresponding measurements of five adults and subadults
     from Berkeley, Alameda County, are: 419 (390-448); 148 (135-160);
     44 (42-47). Tail averages 59 per cent as long as head and body in
     series from Palo Alto and in one from San Francisco. The average
     of 55 for the Berkeley series probably reflects a lesser average
     age. Length of hind foot less than basal length. The type specimen
     measures, 415, 150, 43. It is smaller than the mean.

     Female: A subadult from Palo Alto measures: Total length, 368;
     length of tail, 126; length of hind foot, 39. An adult and two
     subadults from Berkeley measure, respectively, as follows: Total
     length, 347, 365, 340; length of tail, 134, 123, 125; length of
     hind foot, 37, 38.4, 36.5. In these four females the tail averages
     55 per cent as long as head and body. Length of hind foot less
     than basal length.

     The average differences in external measurements of the two sexes,
     as represented by specimens from Berkeley, Alameda County, are:
     Total length, 68; length of tail, 21; length of hind foot, 7.
     Eight adult males weigh 249 (217-335) grams and one adult female
     123 grams.

     _Externals._--Longest facial vibrissae brownish like dark color of
     head and extending beyond ear; carpal vibrissae mostly color of
     underparts and extending to apical pad of fifth digit; hairiness
     of foot-soles slightly more than shown in figure 20.

     _Color._--Spot between eyes, band, confluent with color of
     underparts, on each side of head extending anterodorsally anterior
     to ear, and posterior third of each upper lip tinged with color of
     underparts or, less often, pure white; chin and lower lips white;
     remainder of sides and top of head posteriorly to, or a little
     behind, a line connecting posterior margins of ears, blackish;
     inside of pinna of ear, and sometimes outside of pinna, blackish;
     dark spot posterior to each angle of mouth present on each side in
     three-fourths of specimens; tip of tail black; remainder of upper
     parts near (_l_) Antique Brown, and with more yellow than tone 3
     of Raw Umber of Oberthür and Dauthenay, pl. 301. Often with more
     blackish and red in winter. Underparts near (_a_ to _c_)
     Ochraceous-Buff or Ochraceous-Salmon. Ochraceous-Salmon in some
     juveniles. Color of underparts extends distally on posterior sides
     of forelegs over toes onto antipalmar faces of feet and wrists,
     and on medial sides of hind limbs over antiplantar faces of toes.
     Least width of color of underparts averaging, in 17 adult males
     (Berkeley, 5; San Francisco, 5; Palo Alto, 7), 55 (40-73) per cent
     of greatest width of color of upper parts. Black tip of tail in
     same series of males averaging 51 (35-60) mm., thus averaging
     longer than hind foot and 33 per cent of length of tail (Palo Alto
     and San Francisco, 31 per cent; Berkeley, 35 per cent). In 8 adult
     females, least color of underparts amounts to 55 (47-62) per cent
     of greatest width of color of upper parts. Black tip of tail
     averages 41.5 (28-50) mm., thus averaging longer than hind foot
     and 32 per cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on six adults from Stanford Univ.
     and vicinity): See measurements and plates 22-24; weight (four
     adults), 5.4 (5.0-5.9) grams; basilar length, 47 (46.1-48.1);
     zygomatic breadth more than distance between condylar foramen and
     M1, or than between anterior palatine foramen and anterior margin
     of tympanic bulla; mastoid breadth more than postpalatal length;
     postorbital breadth less than length of upper premolars (less than
     distance between posterior borders of P4 and P2) and less than
     width of basioccipital measured from medial margin of one foramen
     lacerum posterior to its opposite; interorbital breadth not
     greater than distance between foramen opticum and anterior margin
     of tympanic bulla; breadth of rostrum less than length of tympanic
     bulla; least width of palate less than lateral length of P4;
     anterior margin of tympanic bulla as far posterior to foramen
     ovale as width of 3 or 4 (including I3) upper incisors; height of
     tympanic bulla more than distance from its anterior margin to
     foramen ovale; length of tympanic bulla more or less than (about
     equal to) length of lower molar and premolar tooth-row and longer
     or shorter (usually shorter) than rostrum; anterior margin of
     masseteric fossa below anterior half of m2.

     Female (based on three adults, Hayward, Palo Alto, and Morro): See
     measurements and plates 34-36; weight (no. 43574, from Morro) 2.7
     grams; basilar length, 41.2 (40.2-42.2); zygomatic breadth more or
     less than distance between condylar foramen and M1 and more or
     less than distance between anterior palatine foramen and anterior
     margin of tympanic bulla; postorbital breadth less than length of
     upper premolars and less than width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite;
     least width of palate less than lateral length of P4; tympanic
     bulla as far posterior to foramen ovale as width of 3 (including
     I3) upper incisors; height of tympanic bulla more than distance
     from its anterior margin to foramen ovale; length of tympanic
     bulla more than length of lower molar and premolar tooth-row and
     longer or shorter than rostrum.

     The skull of the female averages 50 per cent lighter than that of
     the average male.

     Comparisons of the skull of the male with those of _M. f.
     latirostra_, _pulchra_, _xanthogenys_, and _munda_ are made in the
     accounts of those subspecies.

_Remarks._--Like _M. f. latirostra_, _nigriauris_ long bore the name
_xanthogenys_. The fairly adequate lot of specimens is divided between
the collections of several institutions. The most satisfactory material
in any one collection is in the Stanford University Natural History
Museum where local specimens have been accumulated over a period of
many years.

No actual intergrade between _nigriauris_ and _xanthogenys_ has been
seen, although the specimens from Los Banos, referred to _xanthogenys_,
have large skulls as in _nigriauris_. Intergradation with _latirostra_
is shown by specimens, referred to _latirostra_, from the Los Angeles
area. Also the one adult male from 5 miles southeast of Santa
Margarita, San Luis Obispo County, is of small size and in this respect
approaches _latirostra_. The range of _nigriauris_ is separated from
that of _munda_ by San Francisco Bay, Carquinez Straits, and I suppose
by the lower part of the San Joaquin River. On the basis of color of
the inside of the pinna of the ear, the two subspecies are uniformly
distinct. Intergradation is assumed to occur through the subspecies
_xanthogenys_.

None of the 26 adult and subadult specimens examined for evidences of
infestation of the frontal sinuses by parasites shows malformation of
the sinuses.

     _Specimens examined._--Total number, 103, arranged by counties
     from north to south. Unless otherwise indicated specimens are in
     the Museum of Vertebrate Zoölogy.

     =California.= _Contra Costa County_: Glen Frazer Station, 1; 2 mi.
     W Pinole, 1[13]; 1 mi. E Pinole, 1; Richmond, 1[13]; Lafayette, 1;
     7 mi. E Clayton, 1; Moraga Valley, 1; Pinehurst, Redwood Canyon,
     1; Concord, 1. _Alameda County_: Berkeley, 11; Oakland, 1;
     Piedmont, 1; Haywards, 2; near Haywards, 2; 10 mi. E Haywards,
     1[91]; Redwood Canyon, 1; Calaveras Dam, 1. _San Francisco
     County_: San Francisco, 11 (5[8], 2[91], 1[60], 1[7]); Ocean View,
     1[68]; Visitation Valley, 1. _San Mateo County_: Moss Beach, 1;
     Half Moon Bay, 1; Redwood City, 1[87]; Menlo Park, 9 (5[87],
     2[68]); no locality more definite than county, 1[8]. _Santa Clara
     County_: 1/4 mi. N Milpitas, 1; 1/4 mi. S Milpitas, 1; Stanford
     University, 6 (4[68], 2[91]); Palo Alto, 11 (6[41], 2[60], 1[75],
     1[87]). _Santa Cruz County_: 3 mi. E Santa Cruz, 1; 2-1/2 mi. E
     Santa Cruz, 1; Santa Cruz, 6 (2[91], 1[68], 1[4]). _Monterey
     County_: 1 mi. E mouth Salinas River, 10 ft., 1[37]; Pacific
     Grove, 1[8]; Monterey, 2 (1[7]); Carmel, 1[8]; Carmel Valley,
     1[68]; Point Lobos, 1; Gonzales, 1. _San Luis Obispo County_: 5
     mi. SE Santa Margarita, 1; Morro, 1[91]; 3-1/2 mi. S Oceano, 6.
     _Santa Barbara County_: Santa Maria, 1[87]; 5 mi. N Las Cruces, 1;
     7 mi. W Gaviota, 1; Gaviota, 1.


=Mustela frenata latirostra= Hall

Long-tailed Weasel

Plates 1, 22, 23, 24, 34, 35 and 36

    _Mustela frenata latirostra_ Hall, Carnegie Instit. Washington
      Publ. 473:96, November 20, 1936.

    _Putorius xanthogenys_, Baird, Mamm. N. Amer., p. 176, 1858 (part);
      Stephens, California mammals, p. 246, 1906; Merriam, N. Amer.
      Fauna, 11:25, June 30, 1896 (part).

    _Putorius (Gale) brasilianus frenatus_, Coues, Fur-bearing animals,
      p. 142 (part).

    _Mustela xanthogenys xanthogenys_, Miller, U. S. Nat. Mus. Bull.,
      79:99, December 31, 1912; Grinnell, Univ. California Publ. Zoöl.,
      40:102, September 26, 1933.

    _Mustela arizonensis_, Grinnell and Swarth, Univ. California Publ.
      Zoöl. 10, 376, October 31, 1913.

     _Type._--Male, adult, skull and skin; no. 3257, Mus. Vert. Zoöl.;
     San Diego, San Diego County, California; May 20, 1907; obtained by
     Frank X. Holzner.

     Right M1 is missing and the part of the jaw bearing this tooth is
     broken away. With this exception the skull is complete and
     unbroken and the teeth are all present and entire. The skin is
     fairly well made and in good condition except that it is slightly
     soiled.

     _Range._--Altitudinally sea level to 8000 feet (Tahquitz Valley,
     San Jacinto Mountains); Sonoran and Transition life-zones of coast
     and mountains west of Mohave and Imperial deserts of southern
     California from Point Conception and Cuyama Valley southward at
     least to Mexican boundary. See figures 29 and 30 on pages 221 and
     314.

     _Characters for ready recognition._--Differs from _M. f.
     nigriauris_ by having postorbital breadth of adult males and
     females, more, rather than less, than width of basioccipital
     measured from medial margin of one foramen lacerum posterior to
     its opposite; from _M. f. pulchra_ by having tympanic bulla longer
     than rostrum (orbitonasal length) and by near (_l_) Antique Brown
     rather than near (16 _j_) Buckthorn Brown to near (_h_) Yellow
     Ocher color of upper parts.

     _Description._--_Size._--Male: Six adults and subadults from San
     Diego yield average and extreme measurements as follows: Total
     length, 439 (428-449); length of tail, 153 (142-160); length of
     hind foot, 45 (40-47). Corresponding measurements for a series of
     eight adult males from the vicinity of Los Angeles are: 416
     (394-428); 158 (151-166); 44 (40-47). In the series from San Diego
     the tail averages 54 per cent as long as head and body. In the
     series from Los Angeles the average is 61 per cent. Length of hind
     foot in each series, less than basal length. The type specimen
     measures, 435, 142, 42.

     Female: No. 5070, adult, from San Diego, measures 367, 141, 38.
     Nos. 22 and 6748 from Santa Ysabel, measure: 359, 380; 130, 140;
     39, 35. No. 7194 from Jamacha measures, 358, 125, 35. Three adult
     females from Los Angeles yield the following: Total length, 373,
     345, 368; length of tail, 150, 122, 134; length of hind foot,--,
     41, 41. In no. 5070 the tail is 62 per cent as long as the head
     and body and in the three from Los Angeles it averages 60 (55-67)
     per cent. Length of hind foot, in each case, less than basal
     length.

     The average differences in external measurements of the two sexes
     as shown by the six males from San Diego and the four females
     from San Diego County are: Total length, 73; length of tail, 19;
     length of hind foot, 8. Corresponding differences shown by the
     eight males and three females from Los Angeles are: 54, 23, 3.

     _Externals._--Longest facial vibrissae brownish, like dark color
     of head and extending beyond ear; carpal vibrissae mostly color of
     underparts and extending to apical pad of fifth digit; hairiness
     of foot-soles slightly more than shown in figure 20.

     _Color._--Spot between eyes, band confluent with color of
     underparts on each side of head extending anterodorsally anterior
     to ear, and posterior third of each upper lip tinged with color of
     underparts or, less often, white; chin and lower lips white;
     remainder of sides and top of head posteriorly to near line
     connecting posterior margins of ears, blackish; inside of pinna of
     ear, and sometimes outside of pinna, blackish; dark spot posterior
     to each angle of mouth present on each side in three-fourths of
     specimens; tip of tail black; remainder of upper parts near (_l_)
     Antique Brown, and with more yellow than tone 3 of Raw Umber of
     Oberthür and Dauthenay, pl. 301. Underparts Ochraceous-Buff to
     Warm Buff and in some specimens from Los Angeles and Ventura
     counties Ochraceous-Orange, especially in young and juveniles.
     Color of underparts extends distally on posterior sides of
     forelegs over toes onto antipalmar faces of feet and wrists and on
     medial sides of hind limbs over antiplantar faces of toes. Least
     width of color of underparts averaging, in 15 adult and subadult
     males from San Diego County, 54 (35-75) per cent of greatest width
     of color of upper parts. Black tip of tail in same series of males
     averaging 54.5 (46-60) mm. long. Thus averaging longer than hind
     foot and 35 per cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on 6 adults from San Diego
     County). See measurements and plates 22-24. As described in _M. f.
     nigriauris_ except that: Weight (4 specimens), 3.9 (3.8-4.0)
     grams; basilar length 43.8 (41.9-47.0); postorbital breadth more
     than width of basioccipital measured from medial margin of one
     foramen lacerum posterior to its opposite; interorbital breadth
     not less than distance between foramen opticum and anterior margin
     of tympanic bulla; anterior margin of tympanic bulla as far
     posterior to foramen ovale as width of 2 to 2-1/2 (including I3)
     upper incisors; length of tympanic bulla more than length of lower
     molar and premolar tooth-row and longer than rostrum; anterior
     margin of masseteric fossa below m2.

     Female (based on 4 adults from San Diego County): See
     measurements. As described in _M. f. nigriauris_ except that:
     Weight, 2.6 (2.2-2.8) grams; basilar length, 40.0 and 40.1;
     postorbital breadth more than width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite;
     length of tympanic bulla more than length of rostrum.

     The skull of the female averages 34 per cent lighter than that of
     the average male.

The skull of the male of _latirostra_, compared with that of
_nigriauris_, is by weight, more than one-fourth lighter, has a lesser
basilar length, a lesser mastoid breadth, a lesser zygomatic breadth
and a narrower M1. In these features no overlap has been observed
between adults from the general vicinities of the type localities of
the two forms. In adult males of _latirostra_ the postorbital breadth,
with one exception, is more than the combined length of P4 and P3
whereas the reverse is true in adult males of _nigriauris_. Both males
and females of _latirostra_ have a generally smaller skull with
relatively broader interorbital and postorbital parts and the tympanic
bullae are relatively larger, rounder and more inflated.

Compared with the skull of the male of _pulchra_ that of _latirostra_
is, by weight, more than one-fourth lighter, has a lesser basilar and
orbitonasal length, lesser zygomatic and mastoid breadth and a more
nearly flat braincase. In these features no overlap has been observed
between adults from the general vicinities of the type localities of
the two subspecies. Also, in _latirostra_ the tympanic bulla is longer
than the rostrum whereas the opposite is true in _pulchra_. The skull
of _latirostra_ is generally smaller and relatively, on the average,
has the preorbital part of the skull deeper and broader with longer
tooth-rows, although with shorter rostrum, while the zygomatic and
mastoid breadths are less. Study of skulls of subadult females of
_pulchra_ indicate that females of _latirostra_ and _pulchra_ differ in
the same fashion as do males.

_Remarks._--This subspecies long has gone by the name _M. xanthogenys_
and the type locality was generally supposed to be in the vicinity of
San Diego. This supposition seems to have originated with Merriam's
(1896:25) statement that the type locality was "Southern California,
probably vicinity of San Diego." Nevertheless, as set forth in the
account of _M. f. xanthogenys_ the type specimen concerned now is
thought to have come from much farther north.

Although 76 Recent specimens are available from southern California,
additional adults are needed to understand the geographic variation
there. _M. f. latirostra_ may be a composite--made up of more than one
geographic race. Specimens from San Diego County differ so much in
relative length of the tail that at one stage in the present study it
was thought that a difference in this respect existed between the
coastal animals and those from farther inland. Material received later
did not wholly substantiate this view and because of the uniformly
small size of all of the skulls from that county, the animals were
later regarded as of the same subspecies. Eventually, even this
supposed common feature proved to be inconstant for an adult male from
Jamacha, no. 7098, of the San Diego Society of Natural History, and
another adult male from San Marcos, no. 8869, collection of Ralph
Ellis, were later examined and found to have skulls as large as those
of average-sized, adult males of _nigriauris_.

Despite these puzzling local variations, it is established that the
long-tailed weasels of southern California are smaller than those from
farther north. Also, the southern animal averages smaller in weight and
size of skull, and the skull is differently proportioned. Specimens in
series from Los Angeles County definitely are intermediate in size and
shape of skull between _latirostra_ from San Diego County and
_nigriauris_ from, say, Santa Clara County, but definitely more closely
resemble _latirostra_ from San Diego County than they do _nigriauris_.
A skull of a young animal, not here identified to subspecies, from
Potholes, in the Colorado River Valley, 10 miles northeast of Bard,
Imperial County, California, may have closest relationship to _M. f.
latirostra_. Additional comment on this specimen is offered in the
account of _M. f. neomexicana_.

From the asphalt pits of Rancho La Brea, in Los Angeles County, a total
of 57 skulls have been examined, more than half of which are reasonably
complete. I have been unable to learn whether these came from pits
regarded by students of the deposit as wholly Recent, from pits
regarded as of Pleistocene age, or from both. Suffice to say that only
two specimens were found which could be distinguished from skulls of
the subspecies of weasel living in that area today.

These two specimens, lent to me by Professor Chester Stock, were with
other skulls received from the Los Angeles Museum of History, Art and
Science and bore identifying numbers as follows: 16/20-27, the anterior
part of the skull of an adult, and 16, the skull posterior to the
cribiform plate of a subadult or possibly young individual. The latter
has a mastoid breadth of 28.0 millimeters, a tympanic bulla 16.1 long
and other measurements in proportion. It is larger than any specimen of
weasel, of any subspecies, seen from California and in the subgenus
_Mustela_ seems to be exceeded in size only by certain individuals of
_M. f. texensis_. _M. f. neomexicana_ attains relatively large size and
comparisons were made with individuals of that subspecies. However, the
young specimen from Rancho La Brea differs from _neomexicana_ in that
the tympanic bullae rise less steeply on the medial sides and the
inferior lip of the external auditory meatus is less developed
laterally. Age considered, the sagittal crest is less developed and the
mastoid processes project more abruptly from the skull. The anterior
part of the skull of the adult, no. 16/20-27 is larger than any
specimen seen of _M. f. latirostra_ or adjoining subspecies, and among
California-taken specimens is equaled in size only by the largest males
of _M. f. munda_ from the northwest coastal district in Mendocino
County. This adult from Rancho La Brea differs from _neomexicana_, sex
and age taken into account, in greater postorbital breadth, lesser
rostral width in comparison with the interorbital breadth, and in
having the temporal ridges at the anterior end of the sagittal crest
spread out into a Y-shaped, rather than a T-shaped, pattern. All these
differences from _neomexicana_ are features of agreement with the
California bridled weasels of the subspecies _latirostra_,
_nigriauris_, and _munda_. The same is true of the characters which set
apart the young specimen from _neomexicana_. In summary: of 57 weasel
skulls examined from the asphalt pits at Rancho La Brea, Los Angeles
County, all but two are indistinguishable from the skulls of the Recent
weasel living in that region today. These two skulls agree in
qualitative characters with animals of the California coastal
subspecies now living from Los Angeles northward to Humboldt County,
but are larger. For the time being these two may be thought of as
giants of the same type of animal inhabiting the Los Angeles region
today.

Only one of 41 adult and subadult skulls examined for malformation of
the frontal sinuses shows infestation by parasites.

     _Specimens examined._--Total number, 142, listed by counties from
     north to south. Unless otherwise indicated specimens are in the
     Museum of Vertebrate Zoölogy.

     =California.= _Santa Barbara County_: Rincon Point, 1. _Ventura
     County_: Cuyama Valley, 2200 ft., 1[91]; Nordhoff, 3[59]; Santa
     Paula, 1[59]; Ventura, 7. _Los Angeles County_: near Owensmouth,
     1[24]; Cahuenga, 1[91]; Llano, 10 mi. E Littlerock, 1; Flint
     Ridge, Pasadena, 1[59]; Pasadena, 3; Lankershim, 1[24]; 1 mi. S
     Lankershim, 1[24]; Duarte, 1[59]; Covina, 1[59]; Claremont, 1[91];
     El Monte, 4 (2[75], 1[24]); Montebello, 1; Alhambra, 6 (5[2],
     1[91]); El Nogal, 2[8]; Gardena, 1[26]; Palos Verdes Estate, 3;
     Rancho La Brea asphalt deposits, 57[70]^{ and }[92]. _San
     Bernardino County_: San Bernardino Valley, 1[75]; San Bernardino,
     4 (2[20], 1[91]); Redlands, 2 (1[38]); Bluff Lake, 2 (1[59],
     1[33]). _Riverside County_: West Riverside, 1; Arlington, 800 ft.,
     1[17]; 3-1/2 mi. E and 1/2 mi. N Beaumont, 2600 ft., 1; Banning,
     1[91]; Cabazon, 1[91]; San Jacinto Plain, 1[20]; Tahquitz Valley,
     8000 ft., 1; Elsinore, 1[1]. _San Diego County_: Twin Oaks, 1[91];
     San Marcos, 2 (1[87], 1[41]); Escondido, 1; Witch Creek, 1[91];
     Ballena, 1[20]; Santa Ysabel, 3 (2[20], 1[87]); Julián, 1; La
     Jolla, 1; Lakeside, 1[91]; El Cajon, 1[91]; El Vido (not found on
     map), 1[91]; San Diego, 9 (1[91], 1[20], 1[87], 1[32]); Jamacha,
     2[87]; Chula Vista, 1[20].


=Mustela frenata pulchra= Hall

Long-tailed Weasel

Plates 22, 23 and 24

    _Mustela frenata pulchra_ Hall, Carnegie Instit. Washington Publ.
      473:98, November 20, 1936.

     _Type._--Male, adult, skeleton and skin; no. 16668, Mus. Vert.
     Zoöl.; Buttonwillow, Kern County, California; April 30, 1912;
     obtained by J. Grinnell; original no. 1953.

     The skull (plates 22-24) is complete and unbroken (a fracture in
     the right jugal has healed). All teeth are present and entire. The
     skeleton lacks the os penis, left fibula, shaft of left tibia and
     the distal three or four caudal vertebrae. Some of the bones of
     the feet distal to the radius and tibia are with the skeleton, and
     the remainder probably are in the skin. The skin is fairly well
     made and in good condition, except for the left hind leg which was
     torn when the animal was captured. A well-developed scrotal pouch
     shows the specimen to have been a male.

     _Range._--Altitudinally around 300 feet in San Joaquin Valley to
     2500 feet at Isabella; Upper Sonoran and Lower Sonoran life-zones
     of southern end of San Joaquin Valley and in mountains at southern
     end of Valley, California. See figures 29 and 30 on pages 221 and
     314.

     _Characters for ready recognition._--Differs from _M. f.
     nevadensis_ in presence of light facial markings, and from _M. f.
     nevadensis_ and _M. f. inyoensis_ in near (16 _j_) Buckthorn Brown
     to near (_h_) Yellow Ocher rather than near (14 _n_ to _l_)
     Brussels Brown color of upper parts, and greater size with hind
     foot more than 40 in females and basilar length averaging more
     than 46.0 in males; from _M. f. latirostra_ in having rostrum
     (orbitonasal length) longer than tympanic bulla and from _M. f.
     latirostra_ and _M. f. nigriauris_ by color of upper parts as
     stated above rather than near (_l_) Antique Brown, and by having
     inside of ears same color as back rather than much darker than
     back; from _M. f. xanthogenys_ in hind foot of males more than 46
     and broader skull which in males has breadth of rostrum more than
     13.9 and mastoid breadth more than 26.0.

     _Description._--_Size._--Male: The type specimen and five other
     adults yield average and extreme measurements as follows: Total
     length, 454 (428-477); length of tail, 178 (153-184); length of
     hind foot, 50 (47-55). Tail averages 65 per cent as long as head
     and body. Length of hind foot approximately equal to basal length.
     The type specimen measures, 460, 184, 49.

     Female: Three subadult topotypes yield average and extreme
     measurements as follows: Total length, 399 (383-411); length of
     tail, 154 (140-161); length of hind foot, 42 (41-42). Tail
     averages 63 per cent as long as head and body. Length of hind foot
     less than basal length.

     The average differences in external measurements of the two sexes
     are: Total length, 55; length of tail, 24; length of hind foot, 8.

     _Externals._--As described in _Mustela frenata nigriauris_.

     _Color._--Spot between eyes, band confluent with color of
     underparts, on each side of head extending anterodorsally anterior
     to each ear, posterior third of each upper lip, lower lips and
     chin white or more often darker than Ochraceous-Buff and
     therefore same color as belly; dark spot posterior to each angle
     of mouth present but small; tip of tail black; remainder of upper
     parts near (16 _j_) Buckthorn Brown to near (_h_) Yellow Ocher and
     from tone 2 to 4 of Brown Pink of Oberthür and Dauthenay, pl. 297,
     but with a trifle more reddish brown. Upper parts of uniform color
     except for occasional slight darkening of nose, forehead, and
     areas around eyes. Underparts darker (_a_) than Ochraceous-Buff.
     Color of underparts extends distally on posterior sides of
     forelegs over toes, onto antipalmar faces of feet and wrists, on
     medial sides of hind limbs over antiplantar faces of toes, tarsal
     region and sometimes in diluted fashion on proximal third of
     underside of tail. Least width of color of underparts averaging,
     in 6 male topotypes, 55 (43-81) per cent of greatest width of
     color of upper parts. Black tip of tail in same series of males
     averaging 58 (53-63) mm. long; thus averaging longer than hind
     foot and 33 per cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on 6 ads., type and 5 topotypes):
     See measurements and plates 22-24. As described in _M. f.
     nigriauris_ except that: Weight (6 ads.), 5.3 (4.5-6.1) grams;
     basilar length, 47.6 (46.0-48.6); (one skull, no. 335, with
     postorbital breadth more than distance between posterior borders
     of P4 and P2); interorbital breadth more or less than distance
     between foramen opticum and anterior margin of tympanic bulla;
     anterior margin of tympanic bulla as far posterior to foramen
     ovale as width of 2 to 3-1/2 (including I3) upper incisors; length
     of tympanic bulla more than length of lower molar and premolar
     tooth-row and shorter than rostrum.

     Female: Adult skull of typical female not seen.

As compared with the skull of the type specimen of _inyoensis_, skulls
of adult males of _pulchra_ are larger throughout, relatively broader,
especially in the preorbital part of the skull, have more inflated
tympanic bullae, and are less convex in dorsal outline. Comparison of
the skull with that of _latirostra_ has been made in discussion of that
subspecies. Comparison of skulls of adult males of _nigriauris_ and
_pulchra_ shows that those of _pulchra_ average larger in every
measurement taken except those of m1, M1, P4, and depth of skull at
posterior borders of upper molars. The basilar length is only slightly
more and it follows that, relative to this length, other measurements
of the skull are relatively, as well as actually, larger. In no one
measurement is there an entire lack of overlap, but the skulls of adult
males, and probably adult females, may be distinguished from those of
_nigriauris_ by the combination of the following mentioned, average
differences: Tympanic bullae larger in each of three dimensions;
preorbital and interorbital parts of skull broader and notably heavier;
interorbital breadth greater; zygomatic arches more expanded laterally;
mastoid processes more prominent. As compared with _xanthogenys_,
differences of similar nature, but of greater degree, distinguish
_pulchra_. As compared with those of _nevadensis_ (represented by
specimens from Mono Co., Calif.), skulls of adult males of _pulchra_
average larger in every measurement taken and no overlap exists in
basilar length, orbitonasal length, mastoid breadth, zygomatic breadth,
length of tympanic bulla, or depth of skull at either the anterior
margin of the basioccipital or at the posterior margins of the upper
molars. Relatively, the preorbital portion is about the same size in
the two forms.

_Remarks._--The best material of this big weasel was obtained in 1910
and 1911 by John Wimmer and forwarded to the California Academy of
Sciences through John R. Rowley, although in 1905, one specimen had
been obtained by A. S. Bunnell for the collections of the United States
Bureau of Biological Survey, another by J. Grinnell for the Museum of
Vertebrate Zoölogy in 1912, and in 1933, another by L. M. Huey, for the
San Diego Society of Natural History.

The males from the type locality are relatively uniform in size and
shape of skull. The one exception is no. 137935, U. S. Nat. Mus.,
slightly younger than the others. Its skull is relatively more slender
than any of the others and does not display several of the differential
characters. The male, no. 127566, U. S. Nat. Mus., from Alila (=
Earlimart) is intermediate in cranial features between _pulchra_ and
_xanthogenys_ as known from specimens taken in the vicinity of Fresno.
The skull of the female, no. 127565, from the same place, is too young
to provide diagnostic characters. Since the skull of an adult female of
topotypical _pulchra_ is unknown, doubt attaches to the identification
of the adult, female specimen, no. 115895, U. S. Nat. Mus., from
Delano. It has a relatively broad skull in comparison with the adult
female of _xanthogenys_ from Los Banos. The adult female, no. 9998, San
Diego Soc. Nat. Hist., from 2 mi. SW Simmler, shows approach to
_nigriauris_ in slightly reduced size. The skin alone from Coalinga, a
male, taken on April 10, 1935, measures 462, 179, 47. The adult female,
with crushed skull, from 4 miles east of Coalinga, measures 350, 129,
40. In size, these specimens agree better with _pulchra_ than with
_xanthogenys_. The skin alone from 3 miles south of Coalinga is unsexed
and without external measurements. Skulls of adults from Coalinga are
needed to permit of more positive identification of the subspecies
found there. The female from 4 miles east of Coalinga, taken on
February 21, 1936, is in process of molt on the underparts, and the
longer hair which is near (20´) Naples Yellow contrasts strongly with
the incoming shorter hair which is near (10 _c_) Salmon-Orange. The
skin alone, no. 16270, Mus. Vert. Zoöl., from Isabella, was made up
from a decayed animal and is of but little use. It is referred to
_pulchra_ purely because of geographic nearness of Isabella to the type
locality of _pulchra_. The most that can be told from the specimen is
that it is a relatively light-colored, bridled weasel. The fact that
the color is slightly darker than in _pulchra_ may or may not indicate
intergradation with _nevadensis_. No. 54103/41042, U. S. Nat. Mus.,
consisting of crushed bits of skull and the skin of the head, is from
Willow Spring, Kern County. This marginal locality is really in the
Mojave Desert rather than in the San Joaquin Valley. The light color of
the skin of the head suggests _pulchra_, but it is realized that a
complete specimen might show the animal there to be unlike _pulchra_.

None of the skulls shows evidence of having had the frontal sinuses
infested by parasites.

     _Specimens examined._--Total number, 18, listed by counties from
     north to south. Unless otherwise indicated, specimens are in the
     Museum of Vertebrate Zoölogy.

     =California.= _Fresno County_: Coalinga, 1[23]; 4 mi. E Coalinga,
     1; 3 mi. S Coalinga, 1[8]. _Tulare County_: Alila (= Earlimart),
     2[91]. _Kern County_: Delano, 1[91]; Buttonwillow, 9 (6[8],
     2[91]); Isabella, 1; Willow Spring, 1[91] _San Luis Obispo
     County_: 2 mi. SW Simmler, 1[87].


=Mustela frenata inyoensis= Hall

Long-tailed Weasel

Plates 22, 23 and 24

    _Mustela frenata inyoensis_ Hall, Carnegie Instit. Washington Publ.
      473:99, November 20, 1936.

    _Putorius xanthogenys_, Merriam, N. Amer. Fauna, 11:25, June 30,
      1896 (part).

    _Mustela xanthogenys xanthogenys_, Miller, U. S. Nat. Mus. Bull.,
      79:99, December 31, 1912.

     _Type._--Male, adult, skull (with skeleton) and skin; no. 25907,
     Mus. Vert. Zoöl.; Carl Walter's Ranch, 2 mi. N Independence, Inyo
     County, California; June 26, 1917; obtained by A. C. Shelton;
     original no. 3143.

     The skull (plates 22-24) is complete and unbroken. All teeth are
     present and entire. The skin is well made and in good condition.

     _Range._--From 3700 feet (Lone Pine) to at least 4000 feet
     (Alvord); Lower Sonoran Life-zone of the floor of Owens Valley in
     Inyo County, California. See figures 29 and 30 on pages 221 and
     314.

     _Characters for ready recognition._--Differs from _M. f.
     nevadensis_ in presence of white facial markings; from _M. f.
     pulchra_ in near (_l_) Brussels Brown rather than near (16 _j_)
     Buckthorn Brown to near (_h_) Yellow Ocher color of upper parts
     and basilar length of less than 45 in males; from _M. f.
     latirostra_ in brownish rather than blackish color of inside of
     ear and orbitonasal length of more than 15.

     _Description._--_Size._--Male: Two adults, the type specimen and
     no. 25392/32805, measure, respectively, as follows: Total length,
     423 and 390; length of tail, 170 and 145; length of hind foot, 42
     and 44. Tail is 67 and 59 per cent as long as head and body.
     Length of hind foot less than basal length.

     Female: No. 12400, Field Mus. Nat. Hist., which is young, has the
     following measurements: Total length, 390; length of tail, 150;
     length of hind foot, 39. Tail is 63 per cent as long as head and
     body. Length of hind foot less than basal length.

     The differences in external measurements between the two sexes, as
     represented by the male type specimen and by the young female,
     are: Total length, 33, length of tail, 20; length of hind foot, 3.

     _Externals._--Longest facial vibrissae black or dark brown and
     reaching beyond ear; carpal vibrissae same color as underparts and
     extending to apical pad of fifth digit; hairiness of foot-soles
     (in summer pelage) slightly less than shown in figure 19.

     _Color._--Large spot between eyes, band confluent with color of
     underparts, on each side of head extending anterodorsally anterior
     to each ear, upper throat, chin, lower lips and in some specimens
     part or all of upper lips white; patch between eyes and bars in
     front of ears tinged with some shade of yellowish in one specimen;
     dark spot posterior to each angle of mouth present in four of five
     specimens; tip of tail black; remainder of upper parts, in summer,
     near (_l_) Brussels Brown or tones 1 to 2 of Raw Umber of Oberthür
     and Dauthenay, pl. 301; slightly darker brown on forehead, nose
     and about eyes. In winter near (_j_) Snuff Brown or lighter than
     Brussels Brown with a smoked effect. Underparts Buff-Yellow,
     winter and summer. Color of underparts extends distally on
     posterior sides of forelegs over toes onto antipalmar faces of
     feet and wrists and on medial sides of hind legs over antiplantar
     faces of toes. Least width of color of underparts averaging, in 5
     available specimens 34 (24-42) per cent of greatest width of color
     of upper parts. Black tip of tail, in two adult males, averaging
     53 (45 and 60) mm. Thus longer than hind foot and averaging 34 per
     cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on the type): See measurements and
     plates 22-24. As described in _M. f. nigriauris_ except that:
     Weight, 4.4 grams; basilar length, 44.7; postorbital breadth not
     less than width of basioccipital measured from medial margin of
     one foramen lacerum posterior to its opposite; length of tympanic
     bulla less than length of lower molar and premolar tooth-row.

     Female: Adult unknown.

Compared with the skull of the male of _nevadensis_, no single
difference not covered by individual variation in _nevadensis_ has been
detected. Selected differences of _inyoensis_ in comparison with
_latirostra_ are larger size, less inflated tympanic bullae and
relative narrowness of the postorbital, interorbital and preorbital
parts of the skull. Comparison of the skull with that of _M. f.
pulchra_ is made in the account of that subspecies.

_Remarks._--Although two specimens of this subspecies were taken during
the Death Valley Survey conducted by Dr. C. Hart Merriam, only three
additional individuals are known to have been saved as study specimens
since that time.

_M. f. inyoensis_ as now known may be thought of as closely similar to
_M. f. nevadensis_ except for the presence of well-developed white
facial markings like those found in the weasels of the San Joaquin
Valley and coastal region of California south of San Francisco Bay. The
nonwhite areas of the head are almost the same color as the back and
not distinctly blackish as in _M. f. latirostra_ and _M. f.
nigriauris_. The one specimen in the winter coat, no. 25392/32805, U.
S. Nat. Mus., from Lone Pine, is brown rather than white. The brown has
the pale smoke-tinge common in the winter pelage of subspecies whose
members are either brown or white in winter. The range of this
subspecies is thought to include the floor and lower elevations of
Owens Valley although it may occur in limited numbers southwestward
along the base of the Sierra Nevada and through the mountains in places
of low elevation like Walker Pass its range may meet that of _pulchra_.

The type specimen was taken in an alfalfa field by ranch hands, who,
according to A. C. Shelton (MS), stated that the species was common at
the type locality. None of the five specimens shows infestation of the
frontal sinuses by parasites.

     _Specimens examined._--Total number, 5, listed by localities from
     north to south.

     =California.= _Inyo County_: Alvord, 4000 ft., 1 (U. S. Nat.
     Mus.); 2 mi. N Independence, 1 (Mus. Vert. Zoöl.); Lone Pine, 3 (2
     in Field Mus. Nat. Hist. and 1 in U. S. Nat. Mus.).


=Mustela frenata neomexicana= (Barber and Cockerell)

Long-tailed Weasel

Plates 1, 22, 23, 24, 34, 35 and 36

    _Putorius frenatus neomexicanus_ Barber and Cockerell, Proc. Acad.
      Nat. Sci. Philadelphia, 1898:188; Lantz, Trans. Kansas Acad.
      Sci., 19:178, 1905.

    _Mustela frenata neomexicana_, Miller, U. S. Nat. Mus. Bull.,
      79:100, December 31, 1912; Bailey, Animal Life of Carlsbad
      Cavern, p. 97, 1928; Hall, Carnegie Instit. Washington Publ.
      473:108, November 20, 1936.

    _Mustela frenatus neomexicanus_, Bailey, N. Amer. Fauna, 35:19,
      September 5, 1913.

     _Type._--Male, adult, skull and skin; no. 10475, Mus. Comp. Zoöl.;
     Armstrong's Lake, Mesilla Park, Dona Ana County, New Mexico;
     February 1, 1898; obtained by A. C. Tryson; original no. 58 of C.
     M. Barber.

     The skull is imperfectly cleaned but unbroken. The right upper
     incisors, right P2 and left p3 are broken away. The skin is
     indifferently stuffed but in a good state of preservation except
     that the distal part of the tail is missing. The animal's coat is
     ragged, and this imperfect appearance is heightened by injury to
     the posterior part of the body, probably at the time of capture.

     _Range._--From 3800 feet (type locality) to 9000 feet (Cloudcroft,
     N. Mex.); Upper Sonoran and Lower Sonoran life-zones of northern
     México, southeastern Arizona, New Mexico and western Texas,
     panhandle of Oklahoma, southeastern Colorado and southwestern
     Kansas. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f. frenata_
     and _M. f. texensis_ by Buckthorn Brown rather than Brussels Brown
     color of upper parts, mastoid breadth of adult males ordinarily
     more, rather than less, than postpalatal length; from _M. f.
     leucoparia_ by Buckthorn Brown rather than Argus Brown color of
     upper parts, distance from anterior margin of tympanic bulla to
     foramen ovale less, rather than more, than four-fifths height of
     tympanic bulla; from _M. f. arizonensis_ and _M. f. nevadensis_ by
     Buckthorn Brown, rather than near (14 _n_) Brussels Brown or, in
     winter, white color of upper parts, in presence of white frontal
     spot continuous with color of underparts, in basilar length of
     more than 46 mm. in males and 40 mm. in females; from _M. f.
     longicauda_ by Buckthorn Brown rather than near (_h_) Clay Color
     of upper parts, by presence of white facial markings on Argus
     Brown head, and by length of tooth-rows amounting to less than 37
     per cent of basilar length; from _M. f. primulina_ by Buckthorn
     Brown rather than Brussels Brown color of upper parts, in presence
     of white frontal spot and broad white bands on side of head, in
     anteriorly truncate rather than anterolaterally rounded bullae and
     zygomatic breadth of more than 30 in males and 24 in females.

     _Description._--_Size._--Male: The type specimen (see Barber and
     Cockerell, 1898:188) measured: Total length, 500; length of tail,
     205; length of hind foot, 50. Tail 70 per cent as long as head and
     body. Length of hind foot less than basal length.

     Female: No. 21779 from Tombstone, Arizona, measured: Total length,
     419; length of tail, 165; length of hind foot from dried skin, 41
     (probably 43 in flesh). Tail 65 per cent as long as head and body.
     Length of hind foot less than basal length.

     The average differences in external measurements of the two sexes,
     as known from these two individuals, are: Total length, 81; length
     of tail, 40; length of hind foot, 7.

     Compared with _M. f. frenata_, the size, proportions of parts and
     difference in size of the two sexes, appears to be about the same.

     _Externals._--Longest facial vibrissae colored like upper parts
     [in the type specimen some of the "long bristles of the upper lip"
     are white as pointed out by Barber and Cockerell (_op. cit._:
     188)] and extending beyond ear; carpal vibrissae colored like
     underparts and extending to apical pad of fifth digit; hairiness
     of foot-soles as shown in figure 20.

     _Color._--Broad white bands on sides of head, extending
     anterodorsally anterior to each ear, confluent with white spot
     between eyes and with color of underparts; posterior half or all
     of each upper lip edged with white; usually few white hairs on top
     of head between ears; remainder of top of head near Argus Brown of
     Ridgway and Chocolate, tone 4, of Oberthür and Dauthenay; dark
     spot posterior to each angle of mouth usually absent; tip of tail
     black; remainder of upper parts varying, in different specimens,
     from Buckthorn Brown to Dresden Brown of Ridgway, and Brown Pink
     (tones 3 to 4, pl. 297, of Oberthür and Dauthenay); underparts
     Antimony Yellow or near (_c_) Warm Buff of Ridgway, and Brown Pink
     (tone 1, pl. 297, of Oberthür and Dauthenay); color of underparts
     extends distally on legs over forefeet and hind feet. Least width
     of color of underparts averaging 46 (41-55) per cent of greatest
     width of color of upper parts; black tip of tail 35 to 45 mm. long
     in females; 43 to 68 mm. long in males and averaging 21 (20-36)
     per cent as long as tail-vertebrae.

     No specimen of this subspecies in the white winter coat has been
     seen. Animals taken in midwinter are available from Mesilla Park,
     Willcox, and 10 miles east of Roswell.

     From _M. f. frenata_, _neomexicana_ differs in: upper parts and
     underparts much lighter colored; white facial markings more
     extensive; color of underparts more extended onto feet. From _M.
     f. leucoparia_, _neomexicana_ differs as follows: above and below,
     much lighter colored, but white facial markings less extensive and
     color of underparts less extended onto feet and legs.

     _Skull and teeth._--Male (based on adults: the type; no. 131582
     from Berino, New Mexico; and no. 1485 from Seward Co., Kansas):
     See measurements and plates 22-24. As described in _Mustela
     frenata frenata_ except that: Weight, 6.2 (4.9 and 7.5); basilar
     length, 49.3 (48 and 50.5); mastoid breadth more than postpalatal
     length; least width of palate less than length of P4; anterior
     margin of masseteric fossa directly below m2 or heel of ml.

     Female (based on three adults): See measurements and plates 34-36.
     As described in _Mustela frenata frenata_ except that: Weight, 3.1
     (2.6-3.5) grams; basilar length, 42.7 (40.8-45.5); zygomatic
     breadth less than distance between condylar foramen and M1 and
     more or less than distance between anterior palatine foramen and
     anterior margin of tympanic bulla.

     The skull of the female averages 50 per cent lighter than that of
     the male.

As compared with the skull of the male of _M. f. frenata_, that of
_neomexicana_ is decidedly more angular and ridged. The postorbital
constriction is narrower, the mastoid breadth greater (it is less than
the postpalatal length in some subadult males), the sagittal crest much
higher with impressions of the temporal and masseter muscles carried
farther forward on the frontals, rostrum shorter and tympanic bullae
wider and more inflated. Similar, though less marked, differences exist
between the females. As compared with _M. f. leucoparia_ and _perotae_,
the same differences as noted above between _frenata_ and _neomexicana_
exist. In addition the tympanic bullae are so far removed from the
foramen ovale that the distance from the anterior end of each bulla to
the foramen ovale, instead of being less than the height of tympanic
bullae, is in _leucoparia_ more than four-fifths this height and in
_perotae_ more than the entire height. Also, in _perotae_, the
squamosal, anterior to each tympanic bulla, is ventrally convex rather
than ventrally concave as in _neomexicana_. Compared with _M. f.
longicauda_, _neomexicana_ is relatively narrower in the interorbital
region, has relatively shorter tooth-rows, a V-shaped rather than a
U-shaped interpterygoid space and in males has the interorbital region
flat rather than convex and the sagittal crest is higher. The same
differences are to be noted in comparison with _nevadensis_ but here
the difference in relative length of tooth-row is less. The same
differences exist also in comparison with _M. f. arizonensis_ except
that its interorbital breadth, relative to the rest of the skull, is
about the same. Difference in size is especially marked here; even
females of _neomexicana_ average larger than males of _arizonensis_.

_Remarks._--When Barber and Cockerell named this subspecies in 1898,
they had three specimens. Only two others are known to have been taken
before this time. These are a skeleton, without corresponding skin,
taken at Lozier, Texas, in 1890 by Wm. Lloyd, and no. 21779/36482, U.
S. Nat. Mus., taken on April 6, 1893, by R. D. Lusk at Tombstone,
Arizona. On the back of a label recently attached to the last mentioned
specimen the name C. K. Worthen appears and probably signifies that the
specimen was purchased from this dealer in vertebrate specimens.

_M. f. neomexicana_ has a large geographic range. The old male from
Liberal, Seward County, Kansas, extends the known range far to the
northeast. Geographically, this occurrence is logical for the
southwestern desertlike conditions extend to this part of Kansas.
Probably the subspecies occurs in southeastern Colorado and in the
panhandle of Oklahoma where conditions are similar. Bailey (1905:198)
lists _neomexicana_ as a member of the mammalian fauna of Texas. As
stated by him (_loc. cit._:198) this inclusion is based on geographic
grounds and not on actual specimens. Strecker (1926:13) also includes
_neomexicana_ in his list of Texas mammals but writes me, under date of
January 9, 1928, that "I included _Mustela frenata neomexicana_ as a
Texas mammal on the strength of its being mentioned by Bailey. . . ."
On better ground, Bailey (1928:97) lists the subspecies as occurring in
southeastern New Mexico at Carlsbad Cavern. However, Bailey (_loc.
cit._) knew of the existence of weasels just below El Paso and at
Langtry, Texas. An unsexed skeleton, no. 167891, in the United States
National Museum, from Lozier, Texas, is not certainly identifiable to
subspecies. If, as I think, the animal is a female, its skull is
intermediate between that of _frenata_ and _neomexicana_ although when
all features are considered it is seen to be nearest the latter. The
large size (basilar length of 46.5 mm.) may reflect some relationship
to _texensis_. The field notes of the collector furnished me by Dr. H.
H. T. Jackson (MS), describe the color as brownish yellow above and
sulphur below. The admission of this subspecies to the list of mammals
of Texas is made certain by the female (no. 1572, Texas Cooperative
Research Collection) taken on July 28, 1940, 1-1/2 mi. NW Kent, Texas,
by C. E. Scull.

The skull alone from Durango (City of), extends the known range far to
the south. This skull is typical of _neomexicana_. Skins from the same
place would be especially interesting as showing the approach, if any,
in color, of _neomexicana_ to _M. f. leucoparia_.

Mr. D. D. Stone of Casa Grande, Arizona, writes, under date of February
2, 1927, that a weasel was seen by an acquaintance of his in a field
near Chandler, Maricopa County, Arizona. Probably this was
_neomexicana_. If so, its range extends much farther west than
collected specimens show.

Actual intergradation with _M. f. frenata_ is not shown by the material
at hand. The two females from Albuquerque, although typically
_neomexicana_ as regards color, have smaller, less prominently ridged
skulls than females of _neomexicana_ of the same age from farther south
and approach _M. f. nevadensis_.

Probably the geographic ranges of _M. f. neomexicana_ and _M. f.
latirostra_ do not meet; the only evidence of the existence of weasels
in all of the large area, comprising western Arizona and the deserts of
eastern California, which intervenes between the ranges of the two
subspecies is the skull of a young individual, no. 68842, Mus. Vert.
Zoöl., from 10 miles northeast of Bard, Imperial County, California.
There, on December 29, 1932, Jack C. vonBloeker, Jr., retrieved the
weathered skull with some of the vertebrae attached, from the top of a
wood rat's nest beneath a mesquite tree near the west bank of the
Colorado River.

The idea that the carcass may have been washed down the river from far
upstream gains no support from a comparison of the specimen itself for
the tympanic bullae are larger than in _nevadensis_ and the skull is
larger than the largest males seen of _arizonensis_, the two upriver
races. On the basis of size the skull could be either a male of
_latirostra_ or a female of _neomexicana_. These two subspecies, like
_arizonensis_ and the skull in question, have much inflated bullae.
However, the immaturity of the specimen conceals any other diagnostic
cranial features, and prevents referring it certainly to either
_neomexicana_ or _latirostra_. In any event the specimen provides no
evidence of intergradation between the two forms last mentioned.
Speculating on its identity, I should say that it might be either an
intergrade between _arizonensis_ and _nevadensis_, from southern Utah
or northwestern Arizona, or a member of an unnamed race resident in the
lower part of the valley of the Colorado River.

Whereas _M. f. panamensis_ and _M. f. aureoventris_ are the
darkest-colored weasels and occur in regions of heavy rainfall, _M. f.
neomexicana_ is the lightest-colored American weasel and occurs in an
extremely arid region where the rainfall and humidity are slight.

According to Barber and Cockerell (1898:189) "The type specimen was
shot in the grass on the shore of Armstrong's Lake. . . ." Bailey
(1928:97) found the tracks of one of these animals "in the great pit at
the west entrance to" Carlsbad Cavern and supposes they "hunt the cave
walls for mice and other small game." Data on the label attached to no.
230973 states that the specimen was taken, two miles west of Willcox,
Arizona, in a prairie dog town.

Only two of the 23 skulls show evidence of infestation of the frontal
sinuses by parasites.

     _Specimens examined._--Total number, 28, arranged alphabetically
     by states and from north to south by counties in each state.
     Unless otherwise indicated specimens are in the United States
     National Museum.

     =Arizona.= _Graham County_: Safford, 1. _Cochise County_: 2 mi. W
     Willcox, 1; Willcox, 1; 8000 ft., Chiricahua Mts., 1; 6000 ft.,
     Pinery Canyon, Chiricahua Mts., 1[33]; Tombstone, 1; Sulphur
     Spring Valley, 1[74].

     =Durango.= "Durango City," 1.

     =Kansas.= _Seward County_: Liberal, 1[93].

     =New Mexico.= _Bernalillo County_: 3 mi. NW Albuquerque, 2.
     _Lincoln County_: 7800 ft., South Fork Eagle Creek, White Mts., 1.
     _Chaves County_: Pecos River, 10 mi. E Roswell, 8[74]; Dexter,
     1[74]. _Otero County_: Cloudcroft, 9000 ft., 1[90]. _Dona Ana
     County_: Mesilla Park, 2 (1[75], 1[7]); Berino, 2.

     =Texas.= _Culberson County_: 1-1/2 mi. NW Kent, 1[90]. _Terrel
     County_: Lozier, 1.


=Mustela frenata texensis= Hall

Long-tailed Weasel

Plates 22, 23 and 24

    _Mustela frenata texensis_ Hall, Carnegie Instit. Washington Publ.
      473:99, November 20, 1936.

    _Mustela frenata_, Strecker, The Baylor Bull., 27:14, September,
      1924.

    _Mustela frenata frenata_, Strecker, The Baylor Bull., 27:12,
      August, 1926 (part).


     _Type._--Male, adult, skull with skin of head, neck and tail; no.
     14821, Amer. Mus. Nat. Hist.; Kerr County, Texas; September 17,
     1897; obtained by H. P. Attwater.

     The skull (plates 22-24) and dentition are complete and unbroken.
     The preserved parts of the skin are not stuffed.

     _Range._--Lower Sonoran and possibly Upper Sonoran life-zones of
     central Texas. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _Mustela frenata
     arthuri_ in possessing white facial markings and postorbital
     breadth less than distance between posterior borders of P4 and P2;
     from _M. f. frenata_ in larger size of body and skull, the basilar
     length of which in adult males is more than 52.5; from _M. f.
     neomexicana_ in Brussels Brown rather than Buckthorn Brown color
     of upper parts and basilar length of skull more than 52.5.

     _Description._--_Size._--Male: Measurements taken from the dried
     skins of a young male, no. 15476, Mus. Comp. Zoöl., from Kerr
     County, Texas, and a subadult male, no. 2017, Baylor Univ. Mus.,
     from 5 mi. N Waco, Texas, are, respectively, as follows: Total
     length, 600 and more than 510; length of tail, 200 and 225; length
     of hind foot, 52 and 52.

     Female: Skins unknown.

     _Externals._--As described in _Mustela frenata frenata_.

     _Color._--As described in _Mustela frenata frenata_.

     _Skull and teeth._--Adult male: See measurements and plates 22-24.
     As described in _Mustela frenata frenata_ except that: Weight, 8
     grams; basilar length 54; least width of palate less than length
     of P4; anterior margin of masseteric fossa anterior to middle of
     m2.

     Female: Skull unknown.

_Remarks._--The type specimen, taken by the veteran collector of Texan
mammals, H. P. Attwater, appears to have been the first one of these
animals to find its way into the collection of any museum or
naturalist. The second specimen from Kerr County was secured by, or
through, the well-known commercial collector, F. B. Armstrong. Two
trade skins, from Kerr County, taken on December 10, 1938, are in the
Texas Cooperative Research Collection, as is also the skeleton of a
young animal from Fredericksburg. The two other specimens from McLennan
County (both males contrary to the statement of Strecker, 1924:14), owe
their preservation to the alertness of John K. Strecker, Curator of the
Baylor University Museum, who has given a complete account of their
history.

The range of this subspecies is thought to include much of central
Texas.

The preserved parts of the skin of the type specimen show it to have
been generally large. The part of the tail preserved measures 226
millimeters and the skin of the head and neck is correspondingly large.
The skin alone, no. 427, from near Waco, Texas, has, as now stuffed, a
body 365 millimeters long. Individuals of this race attain larger size
than those of any other American member of the subgenus _Mustela_ with
the possible exception of _Mustela frenata macrophonius_ from Veracruz,
México. In addition to large size, _texensis_ and _macrophonius_ are
analogous in that each has a small geographic range at the northern end
of an extensive range of its similarly colored southern relative from
which it differs mainly in size. Each of the two groups, _goldmani_ and
_macrophonius_ on the one hand and _perotae_, _frenata_ and _texensis_
on the other, has relatively uniform color, color pattern and body
proportions over a large region but at its northern extremity develops
a "giant" population, _M. f. macrophonius_ and _M. f. texensis_,
respectively. The skull of the type specimen of _M. f. texensis_ is the
largest one seen of any American weasel. The type specimen of _M. f.
macrophonius_ has a basilar length that is greater by one-tenth of a
millimeter but in every other measurement taken the skull of _M. f.
texensis_ is the larger. Its weight, 8 grams, also shows it to be
larger.

The broad, white bands in front of the ears are confluent with the
white patch between the eyes on both sides in two specimens and on one
side only in one other specimen. A white patch between the ears is
present in four specimens. The dark spot at each angle of the mouth is
absent on both sides in four specimens and on one side only in one
other specimen. Thus out of a possible twelve cases, the broad bands in
front of the ears are confluent with the spot between the eyes in five
cases. Four of the six specimens have a white spot between the ears.
The dark spot at each angle of the mouth is present three out of a
possible twelve times.

The skull of no. 2017, from five miles north of Waco, is smaller than
either of the two skulls seen from Kerr County and in this respect
approaches _M. f. frenata_. There is no actual evidence of
intergradation with any other subspecies but intergradation probably
does take place with _M. f. neomexicana_ and possibly with _M. f.
arthuri_ and _M. f. primulina_.

Strecker (1924:14) remarks that of the two specimens obtained near
Waco, one was taken in a trap baited for mink and the other was shot in
a hen house. None of the four skulls had the frontal sinuses infested
with parasites.

     _Specimens examined._--Total number, 7, arranged by counties from
     north to south.

     =Texas.= _McLennan County_: 5 mi. N Waco, 1[3]; Erath, 1[3].
     _Gillespie County_: Fredericksburg, 1[90]. _Kerr County_: 4[75];
     1[2]; and 2[90] trade skins.


=Mustela frenata frenata= Lichtenstein

Long-tailed Weasel

Plates 1, 22, 23, 24, 36, 37, 38 and 40

    _Mustela frenata_ Lichtenstein, Darstellung neuer oder wenig
      bekannter Säugethier, 1832, pl. 42, and corresponding text,
      unpaged; Seton, Lives of game animals, 2:576, 1929.

    _Mustela brasiliensis_ Sevastianoff, Mem. de l'Acad. Imp. Sci. St.
      Petersburg, 4:356-363, tab. 4, 1813, name on plate only, the
      description being in the text (not of Gmelin, 1788); Gray, Proc.
      Zoöl. Soc. London, 1865:114.

    _Putorius frenatus_, Baird Mamms. N. Amer., p. 173, 1858; Merriam,
      N. Amer. Fauna, 11:26, pl. 3, figs. 1, 1a, 1b, June 30, 1896;
      Bailey, N. Amer. Fauna, 25:198, October 24, 1905.

    _Putorius (Gale) brasiliensis aequatorialis_ Coues, Fur-bearing
      animals, p. 142, 1877, part? ("merely as a substitute for Gray's
      [supposedly] preoccupied name" that is, _aureoventris_).

    _Putorius (Gale) brasiliensis frenatus_, Coues, Fur-bearing
      animals, p. 142, 1877 (part).

    _Putorius mexicanus_ Coues, Fur-bearing animals, p. 142, 1877,
      [_nomen nudum_, cited by Coues in synonymy as "_Putorius
      mexicanus_, Berlandier, MSS. ic. ined. 4 (Tamaulipas and
      Matamoros)"].

    _Putorius brasiliensis frenata_, Allen, Bull. Amer. Mus. Nat.
      Hist., 3:219, April 17, 1891.

    _Putorius brasiliensis frenatus_, Allen, Bull. Amer. Mus. Nat.
      Hist., 6:197, May 31, 1894; Bangs, Proc. Biol. Soc. Washington,
      10:9, February 25, 1896; Allen, Bull. Amer. Mus. Nat. Hist.,
      8:74, April 22, 1896.

    _Mustela frenata frenata_, Strecker, The Baylor Bull., 27:12,
      August, 1926; Hall, Carnegie Instit. Washington Publ. 473:108,
      November 20, 1936.

     _Type._--Female, adult, skull and skin; no. 991, Berlin Zool.
     Mus., México City, México; June, 1829; obtained by F. Deppe.

     The specimen once mounted, now is remade into a study skin and
     lacks the distal part of the tail. The skull (plates 36-38, 40)
     lacks the basicranial region.

     _Range._--Altitudinally, sea level (Brownsville, Texas) to 7600
     feet (Tlalpam, México); from southern Texas as far south as México
     City; Lower Sonoran to at least Transition life-zone. See figure
     29 on page 221.

     _Characters for ready recognition._--Differs from _M. f. perotae_
     in nonextension of blackish over anterior fourth of neck, least
     width of color of underparts more than 37 per cent of greatest
     width of color of upper parts; height of tympanic bulla more than
     distance from its anterior margin to foramen ovale; from _M. f.
     leucoparia_ by restricted white facial markings that cover less
     than half surface of head in front of ears, by nonextension of
     black of head onto anterior half of neck and by wider (more than
     7.8) tympanic bullae; from _M. f. neomexicana_ by Brussels Brown
     rather than Buckthorn Brown color of upper parts and mastoid
     breadth less than postpalatal length; from _M. f. texensis_ by
     smaller size of body and skull (basilar length in adult males less
     than 52.5); from _M. f. arthuri_ by white facial markings and
     postorbital breadth less than distance between posterior borders
     of P4 and P2; from _M. f. tropicalis_ by nonextension of blackish
     over anterior fourth of neck, least width of underparts more than
     37 per cent of greatest width of upper parts, postorbital breadth
     of adult males less than distance between posterior borders of P4
     and P2.

     _Description._--_Size._--Male: Fifteen adults and subadults from
     Brownsville, Texas, yield average and extreme measurements as
     follows: Total length, 485 (430-556); length of tail, 202
     (165-250); length of hind foot, 48 (40-55). Averages believed to
     be reliable but extremes probably are not. Tail averages 71 per
     cent as long as head and body. Length of hind foot less than basal
     length. Corresponding measurements of an adult male (topotype, no.
     50826) from Tlalpam, México, are: 505, 203, 53. Another adult
     male, from Miquihuana, Tamaulipas, México, measures: 520, 215, 52.

     Female: Six adults, subadults and young from Brownsville, Texas,
     yield average and extreme measurements as follows: Total length,
     420 (362-456); length of tail, 173 (126-200); length of hind foot,
     41 (40-46). Tail averages 70 per cent as long as head and body.
     Length of hind foot more (with possible exception of no.
     36362/48732 U. S. Nat. Mus.) than basal length.

     The average differences in external measurements of the two sexes
     are: Total length, 65; length of tail, 29; length of hind foot, 7.

     _Externals._--Longest facial vibrissae black and reaching beyond
     ear; carpal vibrissae same color as underparts and extending to
     apical pad of fifth digit; hairiness of foot-soles as shown in
     figure 20.

     _Color._--Spot between eyes, broad band, confluent with color of
     underparts, on each side of head extending anterodorsally anterior
     to each ear, and posterior two-thirds to one-half of each upper
     lip, white; remainder of sides and top of head, posteriorly to
     line connecting posterior margins of ears, blackish; dark spot
     posterior to angle of mouth present on both sides in about half
     the specimens; tip of tail black; remainder of upper parts
     Brussels Brown; chin white; remainder of underparts near (16´_a_)
     Ochraceous-Buff (same color in juveniles and young), which color
     extends distally on posterior sides of forelegs over forefeet and
     on medial sides of hind legs to feet and sometimes onto upper
     sides of toes. Least width of color of underparts averaging, in a
     series of seventeen males from Brownsville, Texas, 47 (extremes
     38-53) per cent of greatest width of color of upper parts. Black
     tip of tail, in same series, averaging 49 (extremes 40-55) mm.
     long, thus about equal to length of hind foot and averaging 24 per
     cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on ten adults from Brownsville):
     See measurements and plates 22-24; weight (three adults, one
     topotype and two from Brownsville, Texas), 6.2 (5.3-7.2) grams;
     basilar length, 49.8 (48.2-51.3); zygomatic breadth more than
     distance between condylar foramen and M1 or than between anterior
     palatine foramen and anterior margin of tympanic bulla; mastoidal
     breadth less than postpalatal length; postorbital breadth less
     than length of upper premolars (less than distance between
     posterior borders of P4 and P2) and not greater (usually less)
     than width of basioccipital measured from medial margin of one
     foramen lacerum posterior to its opposite; interorbital breadth
     not greater than distance between foramen opticum and anterior
     margin of tympanic bulla; breadth of rostrum less than length of
     tympanic bulla; least width of palate more or less than length of
     P4; anterior margin of tympanic bulla as far posterior to foramen
     ovale as width of 3 or 4 (including I3) upper incisors; height of
     tympanic bulla more than distance from its anterior margin to
     foramen ovale; length of tympanic bulla more than length of lower
     molar and premolar tooth-row and longer or shorter (usually
     longer) than rostrum; anterior margin of masseteric fossa just
     behind m2.

     Female (based on two adults from Brownsville, Texas): See
     measurements and plates 36-38, 40; weight, 3.4 (3.3-3.5) grams;
     basilar length (six, adult to young) 43.3 (41.3-47.3); zygomatic
     breadth more or less than distance between condylar foramen and M1
     and more than distance between anterior palatine foramen and
     anterior margin of tympanic bulla; postorbital breadth less than
     length of upper premolars and more or less than (about equal to)
     width of basioccipital measured from medial margin of one foramen
     lacerum posterior to its opposite; least width of palate less than
     outside length of P4; tympanic bulla as far posterior to foramen
     ovale as width of 2 to 3-1/2 (including I3) upper incisors; height
     of tympanic bulla more than distance from its anterior margin to
     foramen ovale; length of tympanic bulla more than length of lower
     molar and premolar tooth-row and longer or shorter than rostrum.

     The skull of the female averages 45 per cent lighter than that of
     the average male.

Comparison of the skull with those of _M. f. arthuri_, _tropicalis_,
_perotae_, _leucoparia_ and _neomexicana_ has been made in accounts of
those subspecies. As compared with _M. f. texensis_ (known only from
males), the only difference detected is smaller size.

_Remarks._--As Merriam (1896:27) has said: "In 1813 a Russian
naturalist, Sevastianoff, gave the name '_Mustela brasiliensis_' to a
weasel brought to St. Petersburg by Capt. A. J. Krusenstern on his
return from a voyage around the world. The animal was said to have come
from Brazil, but no definite locality was given." This name was long
applied by many European naturalists to American weasels which had
white facial markings, and several American naturalists adopted the
name. However, Lichtenstein in 1832 applied the name _Mustela frenata_
to the weasels of the vicinity of México City and that name was used
for bridled weasels from México and the southwestern United States by
most subsequent German writers and by several Americans. In 1896
Merriam (1896:27) showed that Sevastianoff's _Mustela brasiliensis_,
1813, although probably the same as _Mustela frenata_, was preoccupied
by Gmelin's _Mustela brasiliensis_, 1788, applied to an otter and that
Lichtenstein's name must be used as the next available one. Since that
time, 1896, _frenata_ has been the name applied to the large
bridled-weasels of Texas and the high table land of México south to
México City. It may be added that in 1937 search by the writer among
the specimens and records at the Russian Academy of Sciences, in
Leningrad, failed to reveal any trace of the type specimen of
Sevastianoff's _Mustela brasiliensis_.

The geographic range of this subspecies is relatively large and, as
might therefore be expected, specimens show geographic variation. The
specimens from Tlalpam, which Merriam (_op. cit._:27) regards as
topotypes, differ in certain respects from specimens from Texas. The
skull of the adult male "topotype," no. 50826, differs from any other
adult male seen in that the basilar length, the length of the upper
tooth-rows, the orbitonasal length, the ratio of the same to the
basilar length, the mastoidal breadth, the zygomatic breadth, the depth
of the skull at the posterior margins of the upper molars, and the
length and breadth of M1, are greater. The height of the tympanic
bullae is less than the average height for these structures in more
northern specimens. The specimens from Tlalpam have also larger
external measurements than the average of more northern specimens. All
of these features show an approach to the subspecies of more southern
distribution. On the other hand, the blackish of the head is not more
intense or more extended posteriorly onto the neck than in specimens
from Brownsville, Texas. The skin, with skull crushed, no. 767, in the
Paris Museum, from 3200 meters elevation near Toluca, does have the
black color of the head extended 30 millimeters posteriorly to the
ears. In this feature, and also in the extensively white face on which
the white bar in front of each ear connects with the frontal spot, as
well as with the color of the underparts, the specimen resembles
_leucoparia_. Better material from the western part of the state of
México may show the range of _leucoparia_ to extend eastward almost or
quite to Toluca.

An adult male, taken on July 15 at Miquihuana, Tamaulipas, is unique in
several respects. The top of its head is black, rather than blackish,
and this color extends posteriorly on the top and sides of the neck
almost halfway to the shoulders. All of the upper parts are much more
darkly colored than in other specimens of this race. The least width of
the color of the underparts is 63 per cent of the greatest width of the
color of the upper parts; thus the color of the underparts is
considerably more extensive than in any other specimen seen. The
underparts are more intensely colored than in the average specimen. The
mastoidal breadth is greater than in any other adult male and amounts
to more than the postpalatal length. On available maps the elevation of
Miquihuana is given as 1892 meters (about 6200 feet). Thus the dark
colors can hardly be ascribed to more tropical conditions than those
under which animals from Brownsville, Texas, live. Brownsville is only
a few feet above sea level and only 235 miles farther north. The
difference noted, therefore, seems to be of geographic significance.
However, there is from Alvarez, San Luis Potosí, approximately 115
miles south of Miquihuana, a young (nearly subadult) female, no. 21968,
which is as light colored as specimens from Brownsville, Texas, or
Tlalpam, México. The only distinctive feature of this specimen is the
much greater extent of its white facial markings; they are more
extensive even than in the specimen from Miquihuana.

Finally, the series from Brownsville, Texas, indicates that the animal
there is smaller than _frenata_ from the vicinity of México (city). The
skull is similarly proportioned except that relative to the basilar
length the orbitonasal length is more. Several other measurements of
the skull of the adult male from Tlalpam, as pointed out above, are
actually, although not relatively, greater than in any specimen from
Brownsville. The similarities between specimens from the two
localities, Tlalpam and Brownsville, are striking; since the two
localities lie at opposite, extreme ends of the range more geographic
variation would be expected. All that is known of the characters of
populations from intermediate localities is that the one specimen from
Alvarez shows no peculiarities whereas the one from Miquihuana suggests
the existence there of a geographic variant.

None of the specimens seen shows actual intergradation with _M. f.
neomexicana_ or with _M. f. arthuri_ but it is supposed that frenata
intergrades with each of these subspecies. The difference between
_frenata_ and _arthuri_ is greater than between _frenata_ and
_neomexicana_. Bailey (1905:198) records tracks of a weasel seen just
below El Paso which he supposed had been made by a weasel of the
_neomexicana_ type. He also cited the taking of a weasel at Langtry
which suggested to him (_op. cit._) ". . . a continuous range from the
country of _frenatus_ up the Rio Grande to the type locality of
_neomexicanus_ at Mesilla Valley," New Mexico. Other records of
occurrence in Texas cited by Bailey, in addition to those provided by
specimens examined by the writer, are San Diego, Beeville, and Port
Lavaca. The Port Lavaca record is the easternmost one assigned to the
subspecies _frenata_; possibly specimens from there would be referable
to _arthuri_.

The series of thirty-four specimens from Brownsville, Texas, permits
measuring the amount of individual and age variation in several
features. For instance, the material is sufficient to show that
external measurements of subadults and those that fall in the upper
part of the category designated as "young" may be included with the
measurements of adults, because the mentioned measurements are not
appreciably greater in adults. The series of skulls, although not
providing more than six of any one age, shows the range of variation in
size and proportion of certain parts and enables the student the better
to evaluate cranial characters of nearby races known from only a few
specimens. For example, not one of the twenty skulls of males from
Brownsville and immediate vicinity is as large as either of the two
specimens of _texensis_ from Kerr County.

The white facial markings vary much in size and shape. In the series of
thirty-four skins from Brownsville the broad white bands in front of
the ears are confluent with the white patch between the eyes on both
sides in three specimens and on one side only in six other specimens.
These bands are confluent with the color of the underparts in all but
two specimens. In one specimen the connection is lacking on both sides
and in the other on one side only. A white patch between the ears is
present in two specimens. The dark spot at each angle of the mouth is
absent on both sides in eleven specimens and absent on one side only in
ten others.

In six other specimens from parts of Texas north of Brownsville, the
broad white bands in front of the ears are confluent with the white
patch between the eyes on both sides in one specimen. A white spot
between the ears is present in one specimen. The dark spot at each
angle of the mouth is absent on both sides in six specimens and on one
side only in three other specimens.

In eleven specimens from México, the broad white bands in front of the
ears are confluent with the white spot between the eyes on both sides
in two specimens and on one side only in one other specimen. The white
spot between the ears is present in one specimen. The dark spot at each
angle of the mouth is absent on both sides, in six specimens, and on
one side only in one other specimen.

Thus, in 51 specimens the broad bands (one in front of each ear) are
confluent with the white patch between the eyes in nineteen out of 100
instances, and not with the color of the underparts in three instances.
A white spot between the ears is present in four specimens. The dark
spot at each angle of the mouth is present 47 out of a possible 98
times.

Four juvenal specimens from Brownsville, Texas, with their dates of
capture and probable age, are as follows: no. 58574, [F], three weeks
old, taken on February 15; no. 17318/24239, [M], four weeks old, taken
on March 16; no. 45899, [F], forty days old, taken on May 21; no.
21778/36481, [M], thirty days old, taken on October 20. In the order
given, the dates of birth of these four juveniles would be
approximately as follows: January 25, February 15, April 1, and
September 20. The dates of birth of other specimens less than three
months old as judged by the stage of development of the skull, and
reckoning backward from the dates of capture, are as follows: April 1,
April 30, May 25, October 12, and December 21. Thus, young appear to be
brought forth at Brownsville, Texas, in the fall, winter and spring,
that is to say from the latter part of September until the latter part
of May.

_Mustela frenata frenata_ is either free of the parasites that infest
the frontal sinuses of most weasels, or withstands their presence
remarkably well, for only one skull shows a definite pathological
condition of the frontal sinuses.

Allen (1896:74) quotes H. P. Attwater, with respect to this species in
Bexar County, Texas, as follows: "Not common, but occasionally met
within the chaparral and cactus lands, where Wood Rats, Rabbits and
Quail abound. They were frequently met with around San Antonio during
the great 'Tramp Rat' [= _Sigmodon hispidus texianus_, see Bailey
(1905:116)] invasion of 1889-90."

     _Specimens examined._--Total number, 63, arranged by counties, and
     in México by states, from north to south. Unless otherwise
     indicated specimens are in the collection of the United States
     National Museum.

     =Texas.= _Bexar County_: San Antonio, 2 (1[2]). _Goliad County_:
     Charco, 1. _Nueces County_: Corpus Christi, 1[2]. _San Diego
     County_ (not found), 1. _Hidalgo County_: La Hacienda, 1. _Duval
     County_: San Diego, 2[7]. _County_ in question: Lower Rio Grande,
     1. _Cameron County_: Brownsville, 34 (3[2], 4[1], 3[93], 2[75],
     1[59], 1[60], 1[4]); no locality more definite than county, 2.

     =Nuevo León.= Río Ramis, 20 mi. NW Montemorelos, 1[90].

     =Tamaulipas.= Matamoros, 6; Miquihuana (now in Nuevo León), 1[75].

     =San Luis Potosí.= Alvarez, 1[75].

     =México=: Region montagneuse des environs de Toluca, Nevada
     Toluca, 3200 M., 1[84]

     =Distrito Federal.= City of México, 2 (1[4]); Tlalpam, 2. No
     locality more definite than México, 4 (1[4], 3[7]).


=Mustela frenata leucoparia= (Merriam)

Long-tailed Weasel

Plates 1, 24, 25, 26, 29, 30, 36, 37 and 38

    _Putorius frenatus leucoparia_ Merriam, N. Amer. Fauna, 11:28, June
      30, 1896.

    _Putorius brasiliensis frenatus_, Allen, Bull. Amer. Mus. Nat.
      Hist., 2:165, October 21, 1889.

    _Putorius frenatus frenatus_, Allen, Bull. Amer. Mus. Nat. Hist.,
      22:259, July 25, 1906.

    _Mustela frenata leucoparia_, Miller, U. S. Nat. Mus. Bull.,
      79:100, December 31, 1912; Hall, Carnegie Instit. Washington
      Publ. 473:108, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 34914/47179, U. S. Nat.
     Mus., Biol. Surv. Coll.; Pátzcuaro, Michoacán, México; July 27,
     1892; obtained by E. W. Nelson; original no. 2960.

     The skull (plates 29 and 30) lacks most of the braincase; a
     fragment, consisting of the supraoccipital and the coalesced
     frontals and parietals remains. The rostrum, left zygomatic arch,
     palate, left pterygoid, left glenoid fossa and right postorbital
     process are intact. The teeth all are present and entire. The
     lower jaw lacks the right coronoid process and the lateral part of
     the articular condyle. The skin is well made and in good
     condition. It differs from an adult male topotype (36855, U. S.
     Nat. Mus.) and other referred specimens in having: the black of
     the head extended farther posteriorly on the neck, the maximum
     amount of white on the head, and a white stripe 50 mm. long
     extending down the middle of the nape from a point between the
     ears more than half way to the shoulders.

     _Range._--Sonoran and Transition life-zones of mountains west of
     México (city) in Michoacán and Nayarit. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f. goldmani_
     in least width of color of underparts more than 47 per cent of
     greatest width of color of upper parts, hind feet colored like
     underparts rather than like upper parts; postorbital constriction
     less than, rather than more than, combined length of upper
     premolars; from _M. f. macrophonius_ by same details of coloration
     as from _goldmani_ and by ventrally concave rather than ventrally
     convex pretympanic part of squamosal; from _M. f. perotae_ by
     least width of color of underparts more than 40 per cent of
     greatest width of color up upper parts; height of tympanic bulla
     more than three-fifths distance from its anterior margin to
     foramen ovale; from _M. f. frenata_ by white facial markings that
     cover half of surface of head in front of ears, by extension of
     black of head onto neck halfway to shoulders and by narrower (less
     than 7.8) tympanic bullae; from _M. f. neomexicana_ by Argus Brown
     rather than Buckthorn Brown color of upper parts and distance from
     anterior margin of tympanic bulla to foramen ovale more, rather
     than less, than four-fifths of height of tympanic bulla.

     _Description._--_Size._--Male: Two adults and one young from Los
     Reyes and Pátzcuaro, Michoacán, yield average and extreme
     measurements as follows: Total length, 514 (510-523); length of
     tail, 206 (196-215); length of hind foot, 55 (52-58). Tail
     averages 67 per cent as long as head and body. Length of hind foot
     more than basal length.

     Female: One adult from Artenkiki, Jalisco, and one subadult from
     Pátzcuaro, Michoacán, measure, respectively, as follows: Total
     length, 412, 400; length of tail, 159, 159; length of hind foot,
     41, 42. Tail averages 64 per cent as long as head and body. Length
     of hind foot equal to or greater than basal length.

     The average differences in external measurements of the two sexes
     are: Total length, 108; length of tail, 47; length of hind foot,
     13.

     _Mustela frenata leucoparia_ has a greater total length and length
     of tail than either _M. f. frenata_ or _goldmani_. The hind foot
     is longer than that of _frenata_ and approximately the same as in
     _goldmani_. Relative to the body length, the tail averages longer
     than that of _goldmani_ and shorter than that of _frenata_.

     _Externals._--As described in _Mustela frenata frenata_.

     _Color._--Broad white bands on sides of head, extending
     anterodorsally anterior to each ear, confluent with white spot
     between eyes and with color of underparts; posterior third of each
     upper lip white; remainder of sides and top of head, and neck
     posteriorly to point halfway to shoulders from ears, black; no
     dark spots at angles of mouth; tip of tail black; remainder of
     upper parts Argus Brown; chin white and sometimes also chest, neck
     and medial sides of hind legs; remainder of underparts near (16´)
     Ochraceous-Buff (near (_a_) Ochraceous-Buff in juvenal female),
     which color extends distally over all of each foreleg (except its
     lateral face proximally from about middle of forearm) and on
     medial side of hind leg and over most of upper side of each foot.
     Least width of color of underparts averaging, in eight specimens,
     54 (extremes 44-61) per cent of greatest width of color of upper
     parts; black tip of tail averaging, in four males, 52 (extremes
     38-78) mm. long, thus averaging 25 per cent of length of
     tail-vertebrae.

     As compared with _M. f. frenata_ and _goldmani_: white facial
     markings more extensive; color of underparts less restricted and
     more extended on legs; black tip of tail relatively of about same
     extent as in _frenata_ and thus much less than in _goldmani_;
     black color of head extending farther posteriorly than in
     _frenata_ but not so far as in _goldmani_.

     _Skull and teeth._--Male (adult): See measurements and plates
     24-26, 29, 30. As described in _Mustela frenata frenata_ except
     that: Weight (no. 128972) 6.3 grams; basilar length, 51.2;
     interorbital breadth less than distance between foramen opticum
     and anterior margin of tympanic bulla; anterior margin of tympanic
     bulla as far posterior to foramen ovale as width of 4 or 5 upper
     incisors; height of tympanic bulla more or less than (about equal
     to) distance from its anterior margin to foramen ovale; anterior
     margin of masseteric fossa anywhere from slightly anterior, to
     slightly posterior, to m2.

     Female (based on no. 26153): See measurements and plates 37-39. As
     described in _Mustela frenata frenata_ except that: Weight, 3.6
     grams; basilar length, 44.5; zygomatic breadth less than distance
     between condylar foramen and M1, or than between anterior palatine
     foramen and anterior margin of tympanic bulla; tympanic bulla as
     far posterior to foramen ovale as width of 4 or 5 upper incisors;
     height of tympanic bulla not more than distance from its anterior
     margin to foramen ovale; length of tympanic bulla more than length
     of lower molar and premolar tooth-row or than length of rostrum.

     The skull of the female is 43 per cent lighter than that of the
     male.

Comparison of the skull with those of _M. f. perotae_, _goldmani_ and
_neomexicana_ has been made in the accounts of those subspecies. As
compared with that of _frenata_ the main difference is the less
inflated tympanic bulla, the height of which is approximately equal to,
rather than decidedly more than, distance from its anterior margin to
foramen ovale.

_Remarks._--The first specimen known to have been preserved is the
alcoholic in the British Museum of Natural History, taken in September,
1891, on the Río Santiago in Jalisco, by D. A. C. Buller. The other
known specimens of this white-faced weasel are divided between the
American Museum and the United States National Museum. The two referred
specimens from Jalisco were the last of several helpful ones collected
in México and Central America by J. H. Batty, and these two were taken
less than three months before Batty's tragic death in Chiapas (see
Allen, J. A., 1906:191). The five specimens from Michoacán were taken
by Nelson or Nelson and Goldman together. Merriam had only three of
these when he named the subspecies and remarked (1896:29) that "This
form is the poorest subspecies described in the present paper."
Although the form is not strongly marked, the two additional specimens
from Michoacán and better comparative material than Merriam had confirm
several of the differential characters ascribed to it by him and
indicate the existence of still other characters.

_M. f. leucoparia_ occurs in the Sonoran and Transition life-zones. No.
27258 from Los Masos, and no. 26153 from Artenkiki (see specimens
examined for other spellings) approach true _frenata_ in coloration.
Each of these specimens has a few white hairs between the ears and the
white patch between the eyes is confluent on one side only with the
lateral white bands on the side of the head. No. 27258 from Los Masos
has a dark spot at each angle of the mouth. The 7 other specimens are
relatively uniform in coloration. Each has the white spot between the
eyes confluent on both sides with the extensive white areas on each
side of the face. None has a dark spot at either angle of the mouth. Of
these 7 specimens, the type specimen and three others have white hairs
forming a median line between the ears and a fifth specimen has a white
spot behind each ear.

_M. f. leucoparia_ is most like _M. f. frenata_. Unlike _frenata_,
_leucoparia_ has tympanic bullae that are less inflated, narrower and
less projected, at their anterior margins, from the cranium. In these
characters _leucoparia_ is intermediate between _M. f. frenata_ and _M.
f. goldmani_. The latter subspecies has the least inflated, narrowest
and least projecting tympanic bullae of the three. The black color of
the head extends, on the average, farther posteriorly than in _M. f.
frenata_ but not so far as in _M. f. goldmani_. The general color, too,
is intermediate between that of _M. f. frenata_ and that of the much
darker _M. f. goldmani_. The white facial markings are more extensive
than in either _M. f. frenata_ or _M. f. goldmani_. This applies to
both the white area between the eyes and the one on each side of the
head between the ear and eye. _M. f. neomexicana_, whose range possibly
meets that of _M. f. leucoparia_, also has more extensive white facial
markings than _M. f. frenata_ but less extensive markings than _M. f.
leucoparia_.

On the basis of skulls alone, specimens of _frenata_ from Tlalpam and
those of _leucoparia_ from Los Reyes can hardly be distinguished. This
fact, and the circumstance that the specimens from the northern part of
the range of _leucoparia_ closely resemble _frenata_ in color,
constitute sufficient evidence for regarding the two as only
subspecifically distinct. The female, no. 26153 from Artenkiki, as
mentioned above, approaches true _frenata_ in coloration. On this
account it is not to be regarded as typical and it was because no other
skulls of adult females were available that this one was used for
comparison with females of allied races.

_M. f. leucoparia_ is, then, a subspecies of the large, temperate-zone
group and is unique in possessing the maximum extent of white facial
markings.

None of the seven skulls shows signs of having had the frontal sinuses
infested with parasites.

     _Specimens examined._--Total number, 8, all from México.
     Localities are listed by states from north to south. Specimens
     from Michoacán are in the United States National Museum; one from
     Río Santiago is in the British Museum of Natural History; all
     others are in the American Museum of Natural History.

     =Nayarit.= Tepic, 1.

     =Jalisco.= Río Santiago, 1; Los Masos, 1; "Artenkiki" (J. A.
     Allen, 1906, p. 238, writes "Artenkikil" and, on p. 259,
     "Artenkiki."), 1.

     =Michoacán.= Zamora, 1; Los Reyes, 1; Pátzcuaro, 3.


=Mustela frenata perotae= Hall

Long-tailed Weasel

Plates 36, 37 and 38

    _Mustela frenata perotae_ Hall, Carnegie Instit. Washington Publ.
      473:100, November 20, 1936.

    _Putorius frenatus_, Merriam, N. Amer. Fauna, 11: pl. 3, fig. 2,
      June 30, 1896.

     _Type._--Female, adult, skull and skin; no. 54278, U. S. Nat.
     Mus., Biol. Surv. Coll.; 12,500 feet, Cofre de Perote, Veracruz,
     México; May 26, 1893; obtained by E. W. Nelson; original no. 4864.

     The skull (plates, 37-39) lacks the right zygomatic arch. Left p2
     is missing. The skin is fairly well made and in good condition
     except that the extreme tip of the tail has been broken off and
     there are two holes in the right hind leg. The underparts show the
     beginning of a spring molt.

     _Range._--From 7500 (?) feet (Perote) to 13,500 feet
     (Popocatépetl), Upper Sonoran, Transition and Boreal life-zones of
     mountains along Puebla-México boundary, eastward to western
     central Veracruz and south into Oaxaca. See figure 29 on page 221.

     _Characters for ready recognition._--Differs from _M. f. frenata_,
     its nearest relative, in extension from head of blackish onto
     anterior fourth of neck; restriction of color of underparts (least
     width of same less than 37 per cent of greatest width of color of
     upper parts), height of tympanic bulla less than distance from its
     anterior margin to foramen ovale; from _M. f. macrophonius_ and
     _M. f. goldmani_ in presence of, rather than absence of, color of
     underparts on hind feet; upper parts (black) Brussels Brown rather
     than Argus Brown or darker; from _M. f. tropicalis_ in larger size
     (adult female with total length more than 400, basilar length more
     than 40, weight of skull more than 3 grams); postorbital breadth
     less than combined length of upper premolars; m1 more than 5.4
     long; from _M. f. leucoparia_ in white facial markings so
     restricted that spot between eyes is not confluent with white
     stripe in front of ear, or, if so, narrowly (less than 4 wide)
     confluent; color of upper parts extending onto antipalmar face of
     forefoot, least width of color of underparts not more than 40 per
     cent of greatest width of color of upper parts; height of tympanic
     bulla not more than three-fifths distance from its anterior margin
     to foramen ovale.

     _Description._--_Size._--Male: A nontypical specimen from Cerro
     San Felipe, Oaxaca, measures: Total length, 500; length of tail,
     205; length of hind foot, 52.

     Female: The type specimen, measures: Total length, 418; length of
     tail, 160; length of hind foot, 45.

     In this male the tail is 70, and in the female, 62 per cent as
     long as the head and body. In each the hind foot is longer than
     the basal length.

     The differences in external measurements between these two
     specimens, representing the two sexes, are: Total length, 82;
     length of tail, 45; length of hind foot, 7.

     _Externals._--As described in _Mustela frenata frenata_.

     _Color_ (based on type specimen).--Color and color pattern as
     described in _Mustela frenata frenata_ except that: blackish of
     sides and top of head extends one-fourth of way back to shoulders
     from ears; throat and breast as well as chin white; remainder of
     underparts near (16´ _c_) Ochraceous-Buff; least width of color of
     underparts equals 36 per cent of greatest width of color of upper
     parts; black tip of tail equal to 28 per cent of length of
     tail-vertebrae.

     _Skull and teeth._--Male (based on a referred specimen from Cerro
     San Felipe which certainly is nontypical): See measurements. As
     described in _Mustela frenata frenata_ except that: Weight, 4.9
     grams; basilar length, 49.2; postorbital breadth more than
     distance between posterior borders of P4 and P2; tympanic bulla as
     far posterior to foramen ovale as width of 5 upper incisors;
     height of tympanic bulla less than distance from its anterior
     margin to foramen ovale; zygomatic breadth less than distance
     between condylar foramen and M1 or than between anterior palatine
     foramen and anterior margin of tympanic bulla.

     Female (based on type specimen, an adult): See measurements and
     plates 37-39. As described in _Mustela frenata frenata_ except
     that: Weight 3.4 grams; basilar length, 43.5; zygomatic breadth
     less than distance between condylar foramen and M1 or than between
     anterior palatine foramen and anterior margin of tympanic bulla;
     postorbital breadth less than width of basioccipital measured from
     medial margin of one foramen lacerum posterior to its opposite;
     tympanic bulla as far posterior to foramen ovale as width of 5 or
     6 upper incisors; height of tympanic bulla one-half to
     three-fifths distance from its anterior margin to foramen ovale;
     length of tympanic bulla more than length of lower molar and
     premolar tooth-row and longer than rostrum.

     The skull of the female is 33 per cent lighter than that of the
     nontypical (and smaller than average) male from Cerro San Felipe.

Comparison of the skull with that of _M. f. tropicalis_ is made in the
account of that subspecies. Compared with the skull of _M. f._
_macrophonius_, that of the female of _perotae_ is more flattened, has
the longitudinal dorsal outline distinctly concave rather than flat
just behind the postorbital processes, and much wider tympanic bullae.
Accordingly, the basioccipital is slightly narrower in _perotae_. The
more marked postorbital constriction of the type specimen of _perotae_
possibly is due to its relatively greater age. As compared with the
skull of _M. f. leucoparia_, that of the female of _perotae_ has less
inflated tympanic bullae, the height of each being half as great as
distance from its anterior margin to foramen ovale, whereas, in
_leucoparia_ (as represented by no. 26153) the two distances are equal.
As compared with that of _M. f. frenata_, the skull of the female of
_perotae_ differs mainly in the lesser inflation of the tympanic bullae
and their relative position. The height of each bulla is in _perotae_
only half as much as, but in _frenata_ more than, the distance from its
anterior margin to foramen ovale. The anterior margin of the bulla is
much less projected from the floor of the braincase in _perotae_. The
squamosal anterior to each bulla is convex ventrally in _perotae_ but
flat or concave ventrally in _frenata_.

_Remarks._--The type specimen and a juvenal female from the town of
Perote were taken in the spring of 1893 by E. W. Nelson. Of these two,
the type specimen was mentioned and figured by Merriam (1898:30, fig.
16 [= fig. 15], pl. 3, fig. 2) as _Putorius frenatus_. The referred
nontypical specimen from Cerro San Felipe, Oaxaca, was referred by
Merriam (op. cit.:29) to _Putorius frenatus goldmani_ with the comment
that it was intermediate ". . . both in coloration and cranial
characters, between typical _frenatus_ and _goldmani_;. . . ." No other
published references to this subspecies, or specimens of it, have been
seen. In 1941 and 1942, W. B. Davis and associates took four specimens
along the boundary between the states of Puebla and México.

Although the specimen from Cerro San Felipe, Oaxaca, is referred to
_Mustela frenata perotae_, to the description of which it answers best,
that specimen, on account of its structural characters and geographic
position relative to adjacent races, is in reality an intergrade
between several of the adjacent races. Some of its intermediate
characters are pointed out in the discussion of _M. f. goldmani_. In
the specimens from 45 and 55 kilometers ESE of México (city) the black
color of the top of the head does not extend so far behind the ears as
in the holotype of _M. f. perotae_ and in this feature the two
specimens show intergradation between the two subspecies, _perotae_ and
_frenata_.

The type specimen taken on May 26, is acquiring new hair on the belly
and lower sides which appears to be the result of a normal molt.

As would be expected from its geographic position, _M. f. perotae_
resembles _M. f. frenata_ of northern México and the high mountain
forms of southern México more than it does the lowland tropical forms.
This is true as regards size of entire animal, proportions of its
parts, and size, general angularity and major proportions of its skull.
The marked postorbital constriction, convex supralacrymal face of
rostrum, width of tympanic bullae and angularity of the braincase place
it nearest _M. f. frenata_ as does also the color and color pattern.
The ventrally convex squamosal anterior to each tympanic bulla and the
slight degree of projection from the cranium of the anterior margin of
each tympanic bulla are intermediate in degree between the condition in
_M. f. macrophonius_ and that in _M. f. frenata_. Thus _M. f. perotae_
combines several characters of _M. f. frenata_ on the one hand with
some of _M. f. macrophonius_ on the other and in some features, for
instance in the size, shape and degree of inflation of the tympanic
bullae, presents intermediate stages of development.

On the eastern plain below the high mountain, Cofre de Perote, there
ranges the similarly colored, smaller, tropical weasel, _Mustela
frenata tropicalis_. Between _M. f. perotae_ and _M. f. tropicalis_
there is marked differentiation in the skulls with much less
differentiation in coloration. The differences in typical skulls of the
two subspecies are so pronounced that one would, at first glance,
hardly believe it possible for direct intergradation to occur between
them on the sides of this mountain. Merriam (1896:30) thought that it
did not. The two skulls figured by him (_op. cit._:31) are a topotype
of _M. f. tropicalis_ from Jico and the one which now is the type
specimen of _M. f. perotae_. They show the great difference in size and
proportions and are females of comparable ages, not of different ages
as I suspected before examining the skulls. However, despite this
marked difference in the skulls, there is some, although not
conclusive, evidence of intergradation furnished by a young female from
Xuchil, Veracruz. This specimen is described in connection with _M. f.
tropicalis_ (see p. 366).

None of the seven skulls shows marked deformity of the interorbital
region, but two of the three adults appear to have had these parts
infested with nematodes.

     _Specimens examined._--Total number, 7, all from México, listed by
     localities from north to south. Specimens from Veracruz and Oaxaca
     in the United States National Museum; remainder in Texas
     Cooperative Research Collection.

     =México=: Monte Río Frío, 45 Km. ESE México City, 1; 55 Km. ESE
     México City, 1; N slope Mt. Popocatépetl, 13,555 ft., 1.

     =Puebla.= Río Otlati, 8700 ft., 1.

     =Veracruz.= Cofre de Perote, 12,500 ft., 1; Perote, 1.

     =Oaxaca.= Cerro San Felipe, 10,000 ft., 1.


=Mustela frenata goldmani= (Merriam)

Long-tailed Weasel

Plates 1, 24, 25, 26 and 30

    _Putorius frenatus goldmani_ Merriam, N. Amer. Fauna, 11:28, June
      30, 1896; Elliot, Proc. Biol. Soc. Washington, 18:236, December
      9, 1905.

    _Mustela frenata goldmani_, Miller, U. S. Nat. Mus. Bull., 79:100,
      December 31, 1912; Hall, Carnegie Instit. Washington Publ.
      473:109, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 77519, U. S. Nat. Mus.,
     Biol. Surv. Coll.; Pinabete, Chiapas, México; February 10, 1896;
     obtained by E. A. Goldman (on attached label collectors recorded
     as Nelson and Goldman); original no. 9279.

     The skull (plates 24 and 30) has the rostrum badly injured. All
     the right, and part of the left nasal, the upper part of the right
     maxilla, the postorbital process and intervening area of frontals
     are missing. Each zygomatic arch is broken but the parts are
     present and attached to the skull. The frontal and interorbital
     regions are greatly malformed owing to parasites that infested the
     sinuses. Right I2 and I3, right and left i3, and the medial parts
     of the paraconid and protoconid of right m1 are missing. The light
     facial markings are less extensive than in any of the referred
     specimens. These markings consist of a separate spot between the
     eyes and a white line, confluent with the color of the underparts,
     on each side of the head, that extends from the base of the ear to
     above the eye. The dark color of the underparts is represented at
     the angles of the mouth by a spot on the left side and a similar
     dark area, confluent with the dark color of the face, on the right
     side. The large size, characters of the skull, and scrotal pouch
     on the skin prove the specimen to be a male as stated on the
     label.

     _Range._--Two thousand five hundred feet (El Cipres, Guatemala) to
     9500 feet (near Tecpám, Guatemala), Upper Tropical Life-zone of
     mountains and western coasts of southern México, Guatemala and
     Salvador. See figure 29 on page 221.

     _Characters for ready recognition_ (characters based on
     males).--Differs from _M. f. nicaraguae_ and _M. f. perda_ by
     larger size (total length of adult males more than 489), least
     width of color of underparts not less than 26 per cent of greatest
     width of color of upper parts, weight of skull of adult male more
     than 5 grams; from _M. f. macrophonius_ by smaller size (total
     length of adult males less than 540), skull of male with basilar
     length less than 52.5 and weight less than 6 grams; from _M. f.
     perotae_ (typical specimens of same sex not available) by darker
     color of upper parts which are Argus Brown or darker rather than
     Brussels Brown; nonextension of color of underparts onto hind
     feet; from _M. f. leucoparia_ in least width of color of
     underparts not more than 37 per cent of greatest width of color of
     upper parts; color of underparts not extended onto hind feet;
     black tip of tail two-fifths rather than one-fourth as long as
     tail-vertebrae; height of tympanic bulla less than four-fifths
     distance from its anterior margin to foramen ovale.

     _Description._--_Size._--Male: Four adults yield average and
     extreme measurements as follows: Total length, 508 (500-512);
     length of tail, 196 (185-207); length of hind foot, 55.5 (54-58).
     Tail averages 63 (59-67) per cent as long as head and body. Length
     of hind foot more than basal length.

     Female: Typical specimen unknown.

     _Externals._--Longest facial vibrissae black and reaching beyond
     ear; carpal vibrissae wholly or in part of same color as upper
     parts and reaching as far as hypothenar pad; hairiness of
     foot-soles distinctly less than that shown in figure 20 on page
     60.

     _Color._--Spot between eyes, band, confluent with color of
     underparts, on each side of head extending anterodorsally anterior
     to each ear and posterior third of each upper lip, white;
     remainder of sides and top of head and neck posteriorly to or
     slightly behind shoulders, black; dark spots at angles of mouth
     usually absent; tip of tail black; remainder of upper parts Argus
     Brown or near (_n_) Argus Brown; chin, throat and breast white;
     remainder of underparts near (16' _c_) Ochraceous-Buff; color of
     underparts extending distally on posterior sides of forelegs onto
     medial toes and on hind legs to points between knees and heels.
     Least width of color of underparts, in five adult males, averaging
     28 (extremes 26-33) per cent of greatest width of color of upper
     parts; black tip of tail, in four adult males, averaging 40 per
     cent of length of tail-vertebrae.

     _Skull and teeth._--Male (based on five adults): See measurements
     and plates 24-26, 30; weight, 5.4 (5.3-5.5) grams; basilar length,
     49.9 (49.6-51.3); zygomatic breadth (except in no. 12523 from
     Salvador) more than or equal to distance between condylar foramen
     and M1 or between anterior palatine foramen and anterior margin of
     tympanic bulla. Mastoid breadth less than postpalatal length;
     postorbital breadth more or less than length of upper premolars
     and greater than width of basioccipital measured from median
     margin of one foramen lacerum posterior to its opposite;
     interorbital breadth less than distance between foramen opticum
     and anterior margin of tympanic bulla; breadth of rostrum less
     than length of tympanic bulla; least width of palate more or less
     than length of P4; anterior margin of tympanic bulla as far
     posterior to foramen ovale as width of five upper incisors; height
     of tympanic bulla less than distance from its anterior margin to
     foramen ovale; length of tympanic bulla more than length of lower
     molar and premolar tooth-row and shorter than or equal to length
     of rostrum; anterior margin of masseteric fossa immediately behind
     m2.

     Female: Typical skull unknown.

Comparison of male skull with that of _M. f. perda_ made in discussion
of that form. Comparison with that of _M. f. nicaraguae_ shows similar
differences, some of which are more pronounced. For example, squamosals
anterior to tympanic bullae more convex ventrally and these bullae
project less from braincase than in _M. f. perda_; thus the difference
in these features is greater between _goldmani_ and _nicaraguae_ than
between _goldmani_ and _perda_.

As compared with the skull of the male of _M. f. macrophonius_, each
one of the skulls of the adult males of _M. f. goldmani_ is smaller in
every measurement taken, with two exceptions. The width of the tympanic
bullae was more in three specimens of _M. f. goldmani_ as was also the
depth of the same in three specimens. Relative to the basilar length
all but two of these measurements average less in _goldmani_; the
exceptions are the zygomatic breadth and depth of the skull at the
anterior margin of the tympanic bullae which average more. Relative to
the basilar length, the orbitonasal length and depth of the skull at
the posterior margin of M1 are less in each skull of _goldmani_. Thus,
excepting the width and height of the tympanic bullae and the relative
zygomatic breadth and relative depth of the braincase posteriorly, the
skull of _goldmani_ is shorter and relatively as well as actually
narrower and lighter throughout.

As compared with the skull of the male of _M. f. leucoparia_, that of
_M. f. goldmani_ averages a trifle shorter and no skull of _goldmani_
equals that of _leucoparia_ in actual or relative zygomatic and mastoid
breadths or length or height of tympanic bullae. In depth, the skull of
_goldmani_ averages actually and relatively greater. Its teeth are
smaller. The squamosal anterior to each tympanic bulla is convex
ventrally whereas it is concave ventrally in _leucoparia_ as in
_frenata_.

_Remarks._--When Merriam (1896:28) named this subspecies, he had only
one specimen but he called attention to the more important diagnostic
characters, which additional specimens show pertain to the race as a
whole.

_M. f. goldmani_ in typical form occurs in high mountains of the Upper
Tropical Life-zone and is most closely related to _M. f. frenata_ and
_M. f. macrophonius_. The altitude at which the two specimens were
taken, twenty miles southeast of Teopisca in Chiapas, is not known.
Merriam (1896:28) states that the type specimen was obtained at "about
8200 feet." The specimen taken by Stirton in Salvador comes from 8000
feet and the one obtained by Barber in Guatemala from 9500 feet. The
specimen from Dueñas, the skin alone of a young animal, is not
instructive.

As regards size, _goldmani_ is larger than the immediately adjacent
subspecies from the Lower Tropical Life-zone but is smaller than _M. f.
leucoparia_ or _macrophonius_. As compared with _M. f. frenata_,
_goldmani_ is longer, has an actually as well as relatively shorter
tail, and a much longer hind foot.

The most outstanding difference in externals from _frenata_ is the
naked foot soles.

Molting probably takes place twice each year although actual proof of
this is lacking. In number 133254 from twenty miles southeast of
Teopisca, taken on May 12, the molt is well advanced. Another specimen
from the same place still retains the winter coat.

In color, _goldmani_ is much darker than _frenata_, has less extensive
white facial markings, longer black tip on tail, more restricted color
of underparts, and lacks the extension of color of the underparts onto
the hind feet.

Of the adult males from the high mountains, the type specimen from
Chiapas is lightest, and the one from Salvador is darkest. This
progressively darker color to the southward probably is geographic
variation.

In total length and relative and actual length of tail, the specimen
from Salvador is the smallest of the five adult males from the higher
mountains. In addition to its darker color and smaller size, no. 12523
from Salvador shows certain distinctive cranial characters. The
zygomatic breadth is less than, rather than more than, or equal to, the
distance between the condylar foramen and M1 or than that between the
anterior palatine foramen and the anterior margin of the tympanic
bulla. This difference appears to be correlated with geographic
position, since no. 15953 from Guatemala has the three distances about
equal and therefore is intermediate in this respect between the
specimen from Salvador and those from Chiapas, in which the zygomatic
breadth is greater than the other two measurements. Also in the greater
depth of the skull and smaller size of the teeth, this specimen from
Salvador approaches the subspecies of the Lower Tropical Life-zone. It
has, however, the longest, highest and widest tympanic bullae of any of
the five specimens. The amount of ventral convexity of the squamosal in
front of each tympanic bulla appears not to be greater than in the
other specimens.

As indicative of intergradation with _perotae_, _leucoparia_ and
possibly _frenata_, there is the specimen from Cerro San Felipe,
Oaxaca. The degree of restriction of the color of the underparts is
intermediate between that of _goldmani_ and _leucoparia_. The same is
true as regards the amount of projection from the braincase of the
anterior margins of the tympanic bullae. The squamosal immediately
anterior to each tympanic bulla is flat instead of ventrally convex as
in _goldmani_ or ventrally concave as in _leucoparia_ and _frenata_. In
accordance with the custom adopted in this paper of referring every
specimen to some one subspecies, this specimen from Cerro San Felipe is
referred to _Mustela frenata perotae_, to the description of which it
most nearly answers.

Possibly _goldmani_, as here constituted, is a composite form. The
specimens from the high mountains closely resemble one another.
However, a specimen, no. 68541 from "Finca El Cipres," Guatemala, which
place Mr. G. Goodwin tells me is at an elevation of 2500 feet,
approximately 5 miles north of Retalhuleu, has a basilar length of 47.3
and is correspondingly small in other parts. This suggests the
existence of a small, lowland race on the western side of the central
divide corresponding to _perda_ and _tropicalis_ on the eastern side.
From only a few miles away, at San Sebastian, there is available, the
adult skull of a still smaller animal. This skull only, no. 41026, in
the Berlin Zoological Museum, has a basilar length of 46.1, zygomatic
breadth of 27.4, and other cranial measurements notably smaller than
those of specimens from the high mountains. A skin-only, no. 12038,
collection of Donald R. Dickey, from La Cebia, altitude 2150 feet, near
the city of San Salvador, seemingly represents an animal smaller than
typical _goldmani_. This specimen from La Cebia has the light color of
the underparts extended distally on the hind legs to the tips of the
toes as in _M. f. tropicalis_. However, the upper parts are darker and
resemble those of _M. f. goldmani_. A fourth specimen from only 3500
feet elevation, on the south side of Volcano Tajumulco, Guatemala, no.
41768, Field Museum of Natural History, a subadult male, measures only
490 in total length and has the least color of the underparts so
restricted as to amount to only 22 per cent of the greatest width of
the color of the upper parts. Both these features are suggestive of the
lowland races.

These four specimens indicate that the lowland population on the
western side of the divide is smaller than the mountain population. The
juvenile from Carolina and a young male from Finca Cipres, however,
both closely resemble individuals of _goldmani_ from the higher
mountains. All these animals here are referred to _goldmani_. More
specimens may reveal an amount and a pattern of geographic variation in
weasels of this region that will require application of another
subspecific name.

The female, no. 68540, from Puebla agrees remarkably well with the
skull of the female, no. 132528, of _macrophonius_. Differences
displayed by the specimen from Puebla are its slightly narrower
braincase and longer space between the foramen ovale and anterior end
of the tympanic bulla. Considering the far eastern location of Puebla
(just north of Río Motagua, at 89° W, according to a sketch map
provided by Mr. G. G. Goodwin), this specimen might be expected to show
some approach to the small lowland races. Actually, however, it
displays the characters of _goldmani_ better than does the subadult
female from Volcano San Lucas, which is nearer the metropolis of
_goldmani_, and I assume at a higher elevation than Puebla.

Concerning this weasel Merriam (1896:29) says: "Mr. E. W. Nelson writes
me that this fine weasel is found sparingly in the forest about
Pinabete, Chiapas, at an altitude of 7000 to 8000 feet (2100 to 2500
meters). The type specimen was shot in the afternoon while hunting on a
heavily wooded hill slope. It was heard making long, slow leaps over
the dry, crisp leaves. Coming to a log, it stood up and rested its fore
feet on the log, in which position it was shot by Mr. Goldman."

The specimen taken by R. A. Stirton in Salvador comes from an elevation
of 8000 feet in the rain forest of the Upper Tropical Life-zone. Mr.
Stirton tells me that one morning on visiting his traps set for small
rodents, he found in one the partly eaten remains of a _Heteromys_.
Leaving these remains as found he placed a steel trap beside them and
on the following morning found the male weasel in the trap.

At least three of the ten specimens had the frontal sinuses infested
with parasites.

     _Specimens examined._--Total number, 15, listed by localities from
     north to south, and unless otherwise indicated in the American
     Museum of Natural History.

     =México=: _Chiapas_: 20 mi. SE Teopisca, 2[91]; Pinabete, 1[91].

     =Guatemala=: Puebla, 1; Finca Porvenir, 3500 ft., S slope Volcan
     Tajumulco, 1[60]; Sierra [=? Cerro] Santa Elena, 9500 ft. (near
     Tecpám), 1[60]; Carolina, 1; Volcano San Lucas, 1; "Finca El
     Cipres," 1; "Finca Cipres," 2500 ft., 1; Finca San Isidro, San
     Sebastión, Dept. Retalhuleu, 1[4]; Dueñas, 1[7]; no locality more
     definite than Guatemala, 1[7].

     =El Salvador=: Los Esesmiles, 8000 ft., Chalatenango, 1[59]; La
     Cebia, 2150 ft., near San Salvador, 1[59].


=Mustela frenata macrophonius= (Elliot)

Long-tailed Weasel

Plates 24, 25, 26, 30, 37, 38 and 39

    _Putorius macrophonius_ Elliot, Proc. Biol. Soc. Washington,
      18:235, December 9, 1905.

    _Mustela macrophonius_, Miller, U. S. Nat. Mus. Bull., 79:100,
      December 31, 1912.

    _Mustela frenata macrophonius_, Hall, Carnegie Instit. Washington
      Publ. 473:109, November 20, 1936.

     _Type._--Male, adult, skull and skin; no. 14063, Field Mus. Nat.
     Hist.; Achotal, Veracruz, México; January 15, 1904; obtained by
     Edmund Heller and Charles M. Barber; original no. 3424.

     The skull (plates 24-26, 30) is complete and unbroken. Excepting
     right P2, which has been aborted or broken away, all the teeth are
     present. The skin is well made and in good condition. As shown by
     the scrotal pouch, the specimen is a male.

     _Range._--Tropical Life-zone, probably into Boreal life-zones, of
     mountains along eastern border of southern Veracruz. See figure 29
     on page 221.

     _Characters for ready recognition._--Differs from _M. frenata
     frenata_ and _M. f. perotae_ and _M. f. leucoparia_ in lacking
     color of underparts on hind feet and in larger skull (skulls of
     adult males with basilar length more than 52.5); from _M. f.
     goldmani_ by larger size of skull (see above) and entire animal
     and wider tympanic bullae; from _M. f. tropicalis_ and _M. f.
     perda_ by larger size (total length of adult males more than 510),
     postorbital breadth amounting to less than combined length of
     upper premolars.

     _Description._--_Size._--Male: External measurements of the type
     specimen, an adult, are: Total length, 598; length of tail, 246;
     length of hind foot, 59. Tail 70 per cent as long as body; length
     of hind foot more than basal length.

     Female: The skin, without field collector's measurements, of an
     adult female from Pérez, Veracruz, shows this sex to be
     correspondingly large. Because the skin is understuffed and
     because the hind feet are skinned out, reliable measurements can
     not be obtained from the dried skin.

     _Externals._--As described in _Mustela frenata goldmani_ except
     that all carpal vibrissae are of same color as upper parts and
     that hairiness of foot-soles is halfway between that shown in
     figures 20 and 21.

     _Color._--As in darkest individuals of _M. f. goldmani_, thus,
     color of upper parts on posterior part of back near (_n_) Argus
     Brown. Color of underparts near (12) Mikado Orange in a juvenile,
     extending distally on posterior sides of forelegs onto inner toes
     and on hind legs to points between knees and heels. Least width of
     color of underparts 28 per cent of greatest width of color of
     upper parts. Black tip of tail 34 per cent of length of
     tail-vertebrae.

     _Skull and teeth._--Male (based on type specimen): See
     measurements and plates 24-26, 30. As described in _Mustela
     frenata frenata_ except that: Weight, 6.9 grams; basilar length,
     54.1; zygomatic breadth less than distance betwee