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Title: Rudiments of Conchology - Intended as a familiar introduction to the science.
Author: Venning, Mary Anne
Language: English
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RUDIMENTS
OF
CONCHOLOGY;
WITH
EXPLANATORY PLATES.
[Illustration: Rudiments of Conchology.]
RUDIMENTS
OF
CONCHOLOGY:
INTENDED AS A
FAMILIAR INTRODUCTION TO THE SCIENCE.
WITH
EXPLANATORY PLATES,
AND
REFERENCES TO THE COLLECTION OF SHELLS IN
THE BRITISH MUSEUM.
BY THE AUTHOR OF
"THE GEOGRAPHICAL PRESENT," &c.
[Illustration: A new and improved Edition.]
LONDON:
DARTON AND HARVEY,
GRACECHURCH STREET.
1837.
LONDON:
PRINTED BY JOSEPH RICKERBY,
SHERBOURN LANE.
ADVERTISEMENT.
The Compiler of the following pages has derived the greater part of the
information contained in them from "The Conchology of Lamarck," from
"Burrows's Elements of Conchology," and other introductory treatises.
In the present Edition of this little Work many alterations and
additions have been made, with the hope of rendering it more useful to
the young student.
ERRATA.
[Note: Corrections were applied.]
Page 3, _for_ Plate 1, _read_ Plate 2.
Page 16, line 8, _for_ squamosa, _read_, squamosus.
Page 20, _for_ candidas, _read_ candida; and _for_ Plate 3,
_read_ Plate 2.
Page 25, _for_ Plates 4 and 5, _read_ Plates 3 and 5; and
_for_ gædaropus, _read_ gæderopus.
Page 27, _for_ epiphippium _read_ ephippium.
Page 35, line 12, _delete_ not.
Page 36, line 14, _read_ Plate 2.
Page 42, _read_ Bruguieres; and _for_ Pollicepes, _read_ Pollicipes.
Page 64, line 3, _read_ Parmophorus--line 6, _read_ Plate 3.
Page 68, line 5 from bottom, _read_ Carocolla.
Page 76, line 6, _for_ Valvata _read_ Voluta.
Page 90, line 4, _read_ anglicanum.
RUDIMENTS
OF
CONCHOLOGY.
CHAPTER I.
INTRODUCTORY.
"A box full of shells!" said Charles to his sister Lucy, who was
looking over her treasures with great attention. "What can you want so
many little shells for?"
"This box and its contents are the gifts of my cousin Jane," replied
Lucy: "she said that I might have her whole collection, if I could find
any pleasure in looking at shells without knowing anything about them.
But I am not _quite_ ignorant of the subject."
"Shells are pretty enough," said Charles; "but how troublesome to
distinguish the differences between each kind! I like plants better
than shells."
[Sidenote: MULTIVALVES, BIVALVES, UNIVALVES.]
"Probably because you are better acquainted with plants," observed his
father, Mr. Elliot, who had just entered the room: "however, the great
naturalist, to whom you are indebted for your knowledge of plants, did
not consider shells as objects beneath his attention."
"You mean Linnæus," said Lucy; "then he, I suppose, separated shells
into the three different divisions--_Multivalves_, _Bivalves_, and
_Univalves_."
"You are right, Lucy," replied her father.
"Pray show me some bivalve shells," said Charles; "I want to know their
forms. A _bivalve_ is a shell with two openings, as I should imagine:
yes, I see that I am right, for you have given me an oyster and a
cockle."
"Here are also _Venus_, _Tellìna_, _Donax_, _Arca_, and _Pinna_,"
observed Mr. Elliot, "all very easy to distinguish."
"'The anchor'd pinna and his cancer friend,'"
repeated Charles. "So the _Pinna_ is a bivalve; but what has _Venus_ to
do with the matter?"
"That is very easy to understand," said Lucy: "the genus called by her
name is remarkable for beauty."
"Now, Charles," said Mr. Elliot, "do you clearly comprehend the verse
that you have just repeated?"
[Sidenote: THE PINNA AND THE CANCER.]
"I have heard that the _Pinna_ is a shell-fish, attended by a _crab_,
'his cancer friend;' but why it is called _anchor'd_ I do not know, but
_cancer_ is Latin for crab."
"Here is a species of _Pinna_," said his father, opening a cabinet;
"and these silken threads are the means by which it fastens itself
to the rocks. The animal is provided with a long foot, with which it
draws out the threads, or _byssus_. The _Pinna_ is sometimes called the
silk-worm of the sea. Lucy, do you know a univalve shell?"
"Oh yes, many!" replied Lucy, "here are rock-shells, cowries, limpets,
and cones. I know the difference between a cowry and a cone; but I am
not yet acquainted with a multivalve shell--will you show me one?"
"_Chiton_, or coat of mail, is a good example," said Mr. Elliot;
"_Pholas_ is another genus of the same division; it has the appearance
of a bivalve. In the _Chiton_ are several _lamina_, or plates, which
are connected by a membrane while the living animal is in the shell;
the membrane is pliant, and the inhabitant has the power of contracting
itself into a ball, when it would avoid injury, like the insect
millepes, that we find under stones in damp places. (Plate 2.)
The curious barnacle-shell, _Lepas_, is another multivalve." (Plate
1.)
"I think we cannot have a more agreeable pursuit for our leisure
hours," said Lucy, "than the study of shells. One can bring them out
or remove them so easily, that they can cause little inconvenience,
which garden-pots often do in town; and then the plants are almost sure
to die, whatever care I take of them."
[Sidenote: LAMARCK'S SYSTEM.]
"Collections of shells are frequently to be seen in London," said
Mr. Elliot, "which are intended for sale. There are now many places
where shells are sold at moderate prices, and young collectors like
yourselves can easily avail themselves of the means thus afforded, to
obtain even a single specimen. While we remain in town you may visit
the British Museum, and become familiar with the rare species of each
genus, of which there are many costly specimens. The arrangement
adopted for that collection is Lamarck's. You will find the work of
this celebrated naturalist on my shelves; it is entitled, '_Histoire
Naturelle des Animaux sans Vertèbres_.' The three last volumes contain
the Conchology."
"It is in French and Latin!" exclaimed Lucy, as she opened a volume.
"Why do you both look so serious?" asked their father. "Are you not
students in those useful languages? To what purpose do you learn a
language if it be not with a view to reading the works of learned men,
whose labours have opened a wide field of knowledge?"
[Illustration: Plate 1.]
[Sidenote: USE OF THE LATIN LANGUAGE.]
"But so many works on science are written in Latin," said Lucy.
"Linnæus, however, has been translated, I know; and as for _British_
botany, we have our own authors in my own dear language."
"The Latin language being universally studied by men of science, it
has become the medium of communication between the learned of most
countries," observed Mr. Elliot. "I should consider a young person of
your age, Lucy, very ignorant who could not read and understand the
general style of Lamarck with the occasional aid of the dictionary."
"Do not be discouraged, brother," said Lucy, "my father will assist
us: remember how frequently he helps us with our lessons now, provided
we do our best. I am resolved to obtain some knowledge of shells this
winter."
"A very good resolution," said Mr. Elliot; "and I predict that your
usual delight on revisiting our favourite country dwelling will be
somewhat increased next spring."
"Because I shall carry down my little collection with the pleasure of
knowing more than I did last year."
"Our own coasts, rivers, and ponds afford a variety of shells. The
hedge-banks, heaths, and other places, possess their inhabitants."
[Sidenote: PLEASURE OF SEARCHING FOR SHELLS.]
"Oh," exclaimed Lucy, "I quite forgot the very pretty snails I have
so often admired on the heath on a dewy morning: why, we may learn
conchology in the open fields as well as botany!"
"Well, then," replied Mr. Elliot, "to-morrow we will apply ourselves
to the needful instruction. I must, however, remind you that I do not
approve of any animal's life being taken away in order to obtain its
habitation. Empty shells are to be found, which will serve perfectly
well for specimens; and should the colour not be so bright as you could
wish, you will have the delightful consciousness that your amusements
have been free from cruelty, and that you have not destroyed the life
of any living, harmless creature, in the pursuit of pleasure. Indeed
there is as much or more gratification in searching among the rocks,
or digging into the sea-sand, with a view to watch the animal in its
natural place, as in possessing its empty shell: and who knows what
grand discoveries you may both make!
"But I must leave you now--be ready for me after our usual
dinner-hour."
CHAPTER II.
[Sidenote: INHABITANTS OF SHELLS.]
"Conchology," said Mr. Elliot, on resuming the conversation with his
children, "is that branch of natural history which comprehends the
study of testaceous animals, or animals with _shell-coverings_, and
includes those of the seas, the rivers, and the land.
"All shells are formed of carbonate of lime. This you may easily
prove by applying a little acid to a shell, and you will find that an
effervescence takes place.
"The animals that inhabit shells are bloodless, without bones, but
provided with a heart, lungs, and mouth, together with other organs
needful to their conformation.
"Testaceous animals have the power of enlarging their habitations; they
can also repair any injury that may occur to them.
"Many kinds of shell-fish are made use of by man, and form a valuable
article of food, such as oysters, cockles, muscles, scallops. The whelk
is also used, and a species of murex.
[Sidenote: FOSSIL SHELLS.]
"A species of cowry is in use for money among some people of Africa;
and pearls, so much valued as articles of ornament, are obtained from
the oyster and mussel genera.
"Within a few years, conchology has become a study of considerable
importance, from its close connexion with geology. Students in the
latter science must be well acquainted with fossil-shells, because they
form so large a portion of organic remains. Species of recent shells,
or those still existing, are also often found in a fossil state, while
many fossil genera are now totally unknown in our earth and waters.
"Thus you perceive that while you are obtaining knowledge in one
science, you are preparing yourselves for making advances in another,
most interesting and wonderful. You, Charles, who are likely to become
a traveller, will perhaps in future years find the advantage of my
present brief lessons.
"I shall first endeavour to make you acquainted with the system of
Linnæus; it is easily learned, and you should be familiar with it, as
it is still adopted by some writers on conchology.
"But in order to understand my instructions, you must have a clear idea
of the terms that I use in describing a shell; now, therefore, give me
your attention while I explain some of those terms to you.
[Illustration: Plate 2.]
[Sidenote: TERMS FOR PARTS OF MULTIVALVES.]
"To begin with the first division, _Multivalves_. There is a group of
_Lepades_, it is the species called goose-barnacle, of which so many
strange and silly tales have been told in former times. (Plate
2, _Lepas anatifera_.) This species is furnished with a kind
of stem, like a bladder, and is called the _peduncle_, (_c_) and is
fastened to other bodies. The _feelers_ (_d_) are feathery projections,
which the animal keeps in continual motion, for the purpose of
catching its food. Here is a group of another kind; (Plate 2,
_Lepas tintinnabulum_;) these are without a peduncle, and are called
_sessile_. The _base_ (_a_) is that part of the shell by which it is
fixed to other bodies: (_a_) the _operculum_ is formed of four small
valves on the summit. (_b_).
* * * * *
"In the shells of the second division, _Bivalves_, we shall find a
greater number of parts. _Valves_ are the different pieces that compose
a shell. When both the valves are alike in form, the shell is called
_equivalve_: when the valves are different in the same shell, it is
called _inequivalve_. _Mya_, _Solen_, _Tellina_, are equivalves:
_Ostrea_, _Anomia_, _Pinna_, &c. are inequivalves.
[Sidenote: TERMS--BIVALVES.]
"The _hinge_ is formed by the teeth of one valve inserting themselves
between those of the other valve, in some genera; in others, by the
teeth fitting into the _cavities_ of the other valve (Plate
3., _a_.) When the teeth are placed in the centre of the hinge
they are called _cardinal teeth_. _Lateral teeth_ are situated on the
sides of the valves, and are generally long and flat, sometimes hollow.
Some hinges are straight, others curved. Here is the hinge of _Arca_,
furnished with many small teeth. (Plate 3, _b_.)
"The _ligament_ is a membrane that connects the valves, and keeps the
hinge in its proper place: it is always situated near the beaks. The
ligament is very perceptible in the cockle, in _Pecten_, or scallop, in
_Tellina_, &c.
"The _beaks_ are the most pointed parts of the bivalve shell (Plate
3, _c_.); when the valves are closed, the line where they meet is
called the _seam_. (Plate 3, _d_.)
"The _anterior slope_ is that part of the shell where the ligament is
placed, and is also called the _area_. (Plate 3, _e_.) The
_posterior slope_, or _areola_, is the other side of the beaks. (_f._)
"The _lunula_ is a crescent-like depression on either the area or
areola. The edge of the valve is called the _margin_; it is often
finely _crenulated_, or toothed. The interior of the valve is called
the _cavity_. (_g._) In the valves of this ark-shell here are two broad
marks, shining and glossy. (_g._) In those of the oyster and muscle
that I now show you, there is but one. These marks are _muscular_
impressions; they are the parts where the muscles of the animal have
been affixed, and are termed _cicatrix_.
[Illustration: Plate 3.]
[Sidenote: TERMS--UNIVALVES.]
"_Ears_ are two processes on each side of the beak; the _Pecten_, or
scallop, is an example. (Plate 3, _i_.)
"_Sinus_, in _bivalve_ shells, is a small hollow in the hinge.
"_Byssus_, or beard, is an appendage composed of silky threads, by
which the muscle and _Pinna_ fasten themselves to the rocks. (Plate
3, _f_.)
"_Cordiform_ is a term applied to heart-shaped shells.
"A _cartilage_ is the same as a ligament. When the valves of a shell
are very nearly flat, they are said to be _compressed_: when a valve
has teeth, it is said to be _dentated_.
"When the valves of a shell do not shut close, they are said to be
_gaping_. (Plate 4, _Mya_.)
"A _muscle_ is a fleshy, pliant organ, by which the animal is attached
to its shell. I have already pointed out to you the impressions of
those muscles within bivalve shells.
"A _suture_ is a toothed joint, in bivalves.
"A shell with ears is said to be _auricled_.
* * * * *
"The third division, _Univalve_ shells, have also their several parts.
The first section has a regular spire. Here are two shells of this
section, _Voluta_ and _Buccinum_, both sawed asunder, in order to show
the interior structure of the shell. (Plate 3.) The aperture,
or opening, being turned _towards you_, the front of a univalve is
seen; reverse it, and you see the back.
[Sidenote: TERMS--UNIVALVES.]
"The top, or highest part, is the _apex_; (_a_) the lowest part is the
_base_ of the shell. (_b._)
"The _spire_ (_c_) is formed of wreaths, or whorls, (_ddd_) which
terminate in the apex: the lowest whorl is the body of the shell. (_e._)
"The _aperture_, opening or _mouth_, (_f_) as it is sometimes called,
is on the right-hand when the front of the shell is turned towards you.
The aperture is an important distinction in univalves: some genera have
a circular opening, as the _Turbo_, or periwincle; some longitudinal,
as the cowry; others semi-lunar, as the _Helix_, or snail genus. (For
examples of these apertures see Plates 1 and 7.)
"The _beak_ is the lengthened process (_g_) at the lower part of the
shell.
"The _canal_, or _gutter_, runs through the beak. (Both these parts are
perceptible in _Murex_ and _Strombus_, Plate 7.)
"_Sutures_ are spiral lines which separate the whorls; they are
sometimes crenated, or notched, sometimes sulcated, or furrowed.
"The _columella_, or _pillar_, extends through the centre of the shell
withinside. The _Buccinum_ and _Voluta_ both show the columella.
(Plate 3.)
[Sidenote: TERMS--UNIVALVES.]
"The _pillar-lip_ of the aperture, or columella margin, is on the
left-hand side of the shell; the _outer_ lip on the right-hand.
Occasionally this order is reversed, but not commonly.
"The _operculum_, or lid, in univalves is that part which fits exactly
into the aperture, and incloses the animal; it serves as a door to the
shell. (Plate 3.) The operculum is either horny, like that of
the periwincle, or of a harder substance, like the shell itself.
"The _umbilicus_ is a circular hole in the body of the shell. This
perforation produces a very curious effect when it is very large. When
the umbilicus is wanting, the shell is called _imperforate_.
"If the spire is truncated, it is _decollated_; if it is surrounded
with spires, it is _coronated_, or crowned.
* * * * *
"Second section, without a regular spire. The _teeth_ in univalve
shells, as the cowry, are ridges upon the aperture. (Plate 1.)
In _Voluta_ they are regular folds or plaits upon the columella.
"A _fissure_ is a notch or slit, as in _Patella fissura_. (Plate
3.)
"Some shells of this section are internally lipped, as _Patella
equestris_; (_Calyptræa_ of other authors, Plate 3;) some are
chambered, as the slipper-limpet; some are cap-shaped, having the apex
much curved--these are the cap-limpets.
[Sidenote: TERMS--UNIVALVES.]
"The _vertex_ in _Patella_ is as the superincumbent part of the shell.
"The _epidermis_ is the outward skin that covers the surface of some
shells.
"_Fauces_ are narrow entrances, as at each end of the cowry.
"_Tubercles_ are protuberances, or knobs, on the surfaces of shells.
"_Striæ_ are raised or flat lines upon the surfaces of shells. When the
surface is marked with lines longitudinally and transversely, it is
_decussated_.
"_Sulci_ are furrows.
"_Fornicated_ signifies arched, greatly excavated.
"_Umbo_ is the swelling part near the beak of bivalve shells; the same
as _boss_.
"_Longitudinal_, running nearly the whole length of the shell in
univalves.
"_Concentric_, having the same centre.
"_Convolute_, when the exterior whorls spirally involve the interior.
"_Varices_, longitudinal, gibbous sutures formed in the shell, at
certain distances on the whorls.
"_Carinated_, having the form of the keel of a boat."
CHAPTER III.
[Sidenote: SYSTEM OF LINNÆUS.]
"As you both assure me," said Mr. Elliot, "that you do not fail to
make yourselves familiar with the _nomenclature_, or terms, used in
conchology, I shall proceed this morning to the arrangement of Linnæus.
"This system is established upon the _outward_ appearances, or external
characters, of the covering bestowed by nature upon the animal, not
upon the form of the animal itself.
"The three principal divisions you are already acquainted with,
namely, _Multivalves_, shells composed of several parts called valves;
_Bivalves_, formed of two parts; and _Univalves_, composed of one part
or piece only.
"These divisions contain several _genera_, and the genera usually
include many individual shells, but occasionally only one.
"The characters of every genus are permanent, and are therefore to be
observed in every one of the species contained in the genus.
"Species are determined by shape, colours, or appearances on the
surface of the shell: there are sometimes many varieties of the same
species.
[Sidenote: LINNÆAN GENERA.]
"The Linnæan genera are thirty-six. I have copied a list of them for
you. In that tray are the specimens mentioned in your list:
ARRANGEMENT OF LINNÆUS.
First Division--_Multivalves_: 3 genera.
* _Chiton_, coat of mail, example, _C. squamosus_.
* _Lepas_, acorn-shell or barnacle, ex. _L. anatifera_ and
_tintinnabulum_.
* _Pholas_, stone-piercer, ex. _P. candida_.
Second Division.--_Bivalves_: 14 genera.
* _Mya_, trough-shell, ex. _M. truncàta_.
* _Solen_, razor-sheath, ex. _S. siliqua_.
* _Tellìna_, wedge-shell, ex. _T. Feroensis_.
* _Cardium_, cockle, ex. _C. cardissa_.
* _Mactra_, kneading-trough, ex. _M. stultòrum_.
* _Donax_, wedge-shell, ex. _D. trunculus_.
* _Venus_, Venus, ex. _V. Paphia_.
_Spondylus_, thorny-oyster, ex. _S. gæderopus_.
_Chama_, clamp-shell, ex. _C. gigas_.
* _Arca_, ark-shell, ex. _A. Noæ_.
* _Ostræa_, oyster, ex. _O. isognomon_.
* _Anomia_. antique lamp, ex. _A. ephippium_.
* _Mytilus_, muscle, ex. _M. edulis_.
* _Pinna_, wing-shell, ex. _P. pectinàta_.
[Sidenote: LINNÆAN GENERA.]
Third Division: 2 sections.--1st. _Univalves_ with a regular
spire: 14 genera.
_Argonauta_, paper-sailor, ex. _A. argo_.
_Nautilus_, sailor, ex. _N. pompilius_. Conus, cone, ex. _C. Hebræus_.
* _Cypræa_, cowry, ex. _C. monèta_.
* _Bulla_, dipper, ex. _B. naucum_.
* _Voluta_, wreath, ex. _V. utriculus_.
* _Buccinum_, whelk, ex. _B. reticulatum_.
* _Strombus_, screw, ex. _S. pes-pelicàni_.
* _Murex_, rock-shell, ex. _M. ramòsus_.
* _Trochus_, top-shell, ex. _T. bifaciàtus_.
* _Turbo_, wreath, ex. _T. muricàtus_.
* _Helix_, snail, ex. _H. nemoràlis_.
* _Nerìta_, nerite, ex. _N. striàta_.
* _Haliòtis_, ear-shell, ex. _H. tuberculàta_.
* * * * *
2nd Section, without a regular spire: 5 genera.
* _Patèlla_, limpet, ex. _P. vulgàta_.
* _Dentàlium_, tooth-shell, ex. _D. elephantìnum_.
* _Sérpula_, worm-shell, ex. _S. triquétra_.
_Terèdo_, ship-worm, ex. _T. navàlis_.
* _Sabella_, Sabella, ex. _S. Belgica_.
Total number of genera in the arrangement of Linnæus, thirty-six.
The genera marked with an asterisk, contain species found in Britain.
[Sidenote: CHITON. LEPAS.]
"Multivalves may be divided into two kinds, the _pedunculated_, or
those fixed to other bodies, as rocks, stones, planks, &c.; or _free_,
as the _Chiton_ and _Pholas_.
"Our first genus is _Chiton_. The shell is easily known. The fixed
character is, many valves placed over each other along the back. I have
already noticed the membrane which connects the valves, which is also a
permanent character. It is elastic: the sides are either scaly, as in
_C. squamòsus_, (Plate 1,) and hairy, or spinous. The species
are determined by the margins. Some of the Chiton genus are
common upon our own coasts; they are frequently found among seaweed and
stones, rolled up like a ball. _C. fasciculàris_ and _C. lævis_ are
British; there are some other British species. The animal adheres to
rocks, like the _Patella_, or limpet. The number of species forty.
"Second genus, _Lepas_. Shell multivalve, fixed at the base; valves
erect, or _upright_.
"Observe how much the situation of the valves differs in _Chiton_ and
_Lepas_. It is scarcely possible to mistake the one for the other.
The feathery tentacula, or feelers, of _Lepas anatifera_ are worthy
notice, and in a state of motion must be yet more beautiful. (Plate
2.) The common acorn-shell, _L. balanus_, is to be seen very
frequently upon the shells of muscles, oysters, periwincles, whelks,
in large groups. I see that you are examining the different appearance
of the pedunculated and the sessile _Lepades_. Linnæus made two
divisions; later writers have separated them into several distinct
genera, which will be noticed when we attend to Lamarck's system. The
species are forty-five, of which several are found on the British
shores, as _L. tulipa_, _L. diadema_, _L. tintinnabulum_, _L. balanus_,
_L. anatifera_, &c. The Indian, American, and Atlantic oceans afford
numerous species.
[Sidenote: PHOLAS.]
"Third genus, _Pholas_. Generic character: shell bivalve, gaping or
divaricated, with several smaller hinges situated upon the hinge; hinge
recurved, with an incurved tooth."
"Father," said Charles, "I must say that the _Pholas_ shell is very
unlike those of the multivalve division: I think it should rank with
bivalves."
"So many conchologists have judged; nevertheless it possesses more than
_two_ valves, and, according to the system, it must be forced into the
division of multivalves.
"The _Pholades_ are found in company, but each individual occupies a
distinct habitation, which the animal excavates for itself, either in
rocks, in wood, coral, or sponge; but the finest specimens are usually
to be seen in chalk. In proportion as the animal increases in size, it
enlarges the cavity in which it is stationed. The animal is supposed
to effect this operation by means of a corroding fluid that is secreted
in the body, and which it has the power of ejecting upon the substance
into which it has entered.
[Sidenote: PHOLAS.]
"The _Pholas_ has the power of emitting a phosphoric liquor, which
shines with brilliancy in the dark.
"I must remind you that the accessory valves are fixed to the margin of
the shell by a gelatinous substance; this decays after the death of the
animal, and consequently the smaller valves are frequently wanting.
"The number of species is twelve. Several of them are found on our
coasts. The _Pholas_ genus is without colour, but the reticulations
in some species are exceedingly delicate. _Pholas candida_ (Plate
2) is found on the shores of Kent; you will be pleased with
the shells. _Pholas dactylus_ is larger and coarser, and not at all
uncommon.
"We have now finished our first division, and must proceed to the
bivalves."
CHAPTER IV.
Second Division.--_Bivalves_: 14 genera.
"I fear," said Charles, "that this new division will be rather
difficult, for my father tells me that we must pay particular attention
to the _hinges_ of bivalve shells."
"Then _apply_ yourself to the study of hinges, Charles, and your
difficulties will chiefly disappear," answered Mr. Elliot.
[Sidenote: MYA.]
"The hinge of _Mya_, the first on the list, is easily known. The
generic characters are, shell gaping at one end, hinge mostly with one
thick spreading tooth, not inserted into the opposite valve. The _Mya_
race burrow in the sand. Here is _Mya arenaria_, a large thick shell,
frequent on the shores of Kent: the large tooth is sufficiently plain
in _this_ species. _Mya truncata_ (Plate 4) is as common, and
the curious membranous case, which you will find attached to one end of
the shell, is a guide to the species. Both these species are without
colour, and have little to attract in their outward appearance. The
genus, however, according to Linnæus, varies exceedingly, and contains
forty-one species.
[Sidenote: SOLEN. TELLINA.]
"_Solen._ Shell bivalve, open at both ends, tooth of the hinge
subulate, or awl-shaped, reflex, often double.
"In this genus, the great length, in comparison with the breadth of
the shells in many of the species, is remarkable: some are exceedingly
brittle. Our example, _Solen siliqua_ (Plate 1) is a British
species. The hinge is not in the centre of the shell, but nearer to
one end of it. Some are shaped like the handle of a knife or a razor,
others are bent resembling the blade of a scimitar. The _Solen_ lives
in the sands of the sea-shore, often burying itself two feet deep, and
retaining its shell in a vertical position: thirty-five species.
"The genus _Tellìna_ is remarkable for the beauty of the shells, and,
according to the arrangement of Linnæus, contains ninety-seven species.
The exterior is sometimes marked with radiations: the surface of some
shells is very finely polished, while in others it is covered with
striæ and undulations. The species that you have placed before me,
Lucy, is _Tellìna Feroensis_; the shell is finely striated, and has
also radiations. (Plate 4.)
"The generic characters are chiefly these: shell compressed towards
the anterior slope, teeth of the hinge mostly three, the lateral ones
smooth, in one valve. Two or three small species are common on our
coasts. I should also observe that there is a convex fold on one valve
and a concave fold upon the other. Many of the _Tellìna_ genus are
found buried in the sea-sands.
[Sidenote: CARDIUM. MACTRA.]
"_Cardium._ Generic character: shell equivalve, convex, ribbed,
striated, or grooved, the margin toothed: hinge with two teeth near the
beak, and a lateral one on each side: fifty-four species.
"Observe how the beaks of this common _Cardium_, cockle, turn inwards,
and the bosses project. Another striking character is the ribs, that
are generally longitudinal, and not concentric or transverse, as in
_Tellìna_, and, as you will see, in _Venus_. _C. aculeatum_ has small
spines on the valves; _C. costatum_, the ribbed cockle, is one of the
finest species of this genus, and _C. cardissa_ is a beautiful shell.
(Plate 4.) The common cockle is _Cardium edule_.
_Mactra._ Generic character: shell bivalve, unequal sided, middle tooth
of the hinge complicated, with a small hollow on each side, and lateral
side-teeth: thirty-seven species.
"The shells of this genus are usually thin, brittle, and remarkably
light. _Mactra stultorum_ is a common species. (Plate 4.)
[Sidenote: DONAX. VENUS.]
"_Donax._ Margin of the shell often crenulate, the anterior slope very
obtuse; hinge with two cardinal teeth, and one lateral tooth.
"The most striking characteristic of _Donax_ is the broad, thick
extremity of one end, gradually lessening towards the other. A rich
purple tint is very frequent in these shells. _Donax denticulatus_ and
_trunculus_ are common British examples. (Plate 4.) You must
remark the ligament of _Donax_, which is exterior.
"Our next genus ranks highest for beauty among the bivalves, and takes
its name from the goddess _Venus_. The species amount to one hundred
and sixteen in the Linnæan system, but other authors have formed
several new genera.
"Shell bivalve, having the lips incumbent on the anterior margin; hinge
with three teeth, all approximate, the lateral ones diverging at the
lip.
"I am afraid," said Lucy, "that we shall find this genus very
difficult: I wish you would tell us the new genera that have been
formed out of it."
"Learn first to know the general appearance of _Venus_, and remark
especially the _teeth_. You may also bear in mind that the _beaks_ are
almost always turned _to_ the posterior slope, and _from_ the ligament.
The area and areola are also very conspicuous: the area is generally
large, and differently coloured to the disk. _Venus Paphia_ is pretty.
(Plate 4.) The spinous species, _V. Diòne_, is more beautiful,
and is the only shell of the genus that has spines. The brown Venus,
_V. chionè_, is very smooth and polished; both species are frequent in
collections. The British shells of this genus are neither numerous nor
very beautiful.
[Illustration: Plate 4.]
[Sidenote: SPONDYLUS.]
"_Spondylus._ Valves unequal, rough; hinge with two recurved teeth,
with a hollow between them; shell sometimes eared. (See Plates
3 and 5.)
"I think," said Lucy, "that the English name, _thorny-oyster_, is not
very suitable: it is more like a scallop; but it differs from both in
having two strong teeth in the hinge, and I observed this morning that
neither the oyster nor the scallop have any hinge."
"So that was the object you had in view," said Charles, "when you
were so quietly handling those shells in the kitchen: I confess I
could hardly help laughing; and now my father will say that _you_ are
'_Eyes_,' and I the '_No Eyes_,' of 'Evenings at Home.'"
"Perhaps I might have made the observation," replied Mr. Elliot; "but
you have reproved yourself, which is far better.
"_Spondylus_ can scarcely be mistaken from any other bivalve shell. The
species _gæderopus_ is remarkable for its projecting beak; the surface
is rough, with either tubercles or spines. Some authors reckon only
four species, others thirteen. The _Spondyli_ are frequently found
attached to rocks at some depth in the ocean. The animal is eaten on
the coasts of the Mediterranean. We have no British _Spondylus_.
[Sidenote: CHAMA. ARCA. OSTREA.]
"_Chama._ Shell thick; hinge with a thick tooth, sometimes crenate,
obliquely inserted into a corresponding channel. (Plate 5.)
The shells of this genus vary greatly, which you will perceive upon
comparing _C. gigas_ and _C. cor_. (See Plate 9, _Isocardia
cor_.) The _Chama_ genus is usually ribbed, foliated, or scaly. _C.
Lazarus_ is a beautiful species: _C. cor_ is a British species, and the
only one. The whole number is twenty-five.
"Here is _Noah's-ark_, an example of the genus _Arca_, and is found on
our own coasts. The long hinge beset with sharp teeth, inserted into
each other, renders the genus sufficiently marked; but in some species
the hinge is curved. The form varies exceedingly. The number of species
is forty-five. (Plate 5.)
"_Ostrea._ In this well-known genus we lose sight of the _toothed_
hinge. Take that _Pecten_, or scallop, which belongs to one division of
_Ostrea_ in this system, and tell me what holds the valves together.
Charles is silent; what says Lucy?"
"Here are the remains of the same kind of substance which we saw in
_Donax_ and in _Venus_. I think it is called the _ligament_."
[Illustration: Plate 5.]
"Very well remembered," continued her father. "The generic character
of this very large portion of bivalves is, shell bivalve, usually with
unequal valves: hinge without teeth, having a hollow cavity or sinus,
and sometimes grooved. Here is a young common oyster, and, according
to the rule of our present system, this shell, _Ostrea isognomon_,
is of the same genus. (Plate 5.) The number of species is
eighty-four, of which thirteen are British. The old shells of common
oysters are often covered with _Serpula_, _Lepas_, and _Anomia_, and
some kinds of corallines.
[Sidenote: ANOMIA. MYTILUS.]
"The next genus, _Anomia_, is remarkable for the thin, delicate, and
almost transparent appearance of the shells. The valves are unequal,
and frequently perforated near the apex; hinge toothless; in the flat
valve, two bony rays.
"_Anomia ephippium_ has a large perforation, through which the animal
passes a ligament, and attaches itself to other substances. These
shells are often to be found on oysters. (Plate 5.) Species
thirty-two.
"_Mytilus._ The principal characters are, shell bivalve, rough, often
affixed by a thick byssus, or beard; hinge without teeth, with a hollow
line extending lengthways. (Plate 3.)
"The common muscle, _Mytilus edulis_, must be well-known to you,
and also the fine polish that the shells will take when cleared of
the rough exterior by artificial means, _Mytilus barbatus_ is not
unfrequent on our shores; the colour is brown, and the shell is shaggy.
Number of species, forty-nine.
[Sidenote: PINNA.]
"Our last bivalve genus is _Pinna_. The generic characters--shell
bivalve, brittle, erect, gaping at one end, throwing out a byssus;
hinge without teeth. (Plate 6.)
"The _Pinna_ race are found plentifully in the Mediterranean, the
Indian, American, and Atlantic oceans: the British seas afford three
species. The genus is noted for producing a fine byssus, that is
manufactured in Italy into various articles, as gloves. The animal is
sometimes used as an article of food.
"An ancient writer asserts that the _Pinna_ is attended by a crab,
that finds a habitation in its shell, and repays the favour by giving
notice, by a gentle nip, when a fish comes within reach; the _Pinna_
opens the valves of the shell, and secures the prey, which serves
for the food of both. Now, Charles, you know the whole sense of the
quotation--
"'The anchor'd pinna and his cancer friend.'"
CHAPTER V.
Third Division.--_Univalves._
"Father," said Lucy, the next time they met to pursue their study, "I
think we have made ourselves familiar with the various hinges of the
bivalve shells, which are becoming favourites with us; but from the
variety of fine specimens which you have on your table, I see that we
shall be much gratified in examining the univalve division."
[Sidenote: ARGONAUTA.]
"My first genus is very beautiful," replied Mr. Elliot; "it is
_Argonauta_, or paper-sailor. The shell is univalve, involute,
unilocular, or without chambers: the aperture cordate. (Plate
6.) These shells are spiral, and remarkably brittle. The argonauts
are supposed to be the shells that taught mankind the use of sails in
the earliest ages of society. In calm weather the animal rises with its
shell to the surface of the water, and spreads its arms over the edge;
these arms answer the purpose of oars. It then spreads a membrane for
a sail, which can be turned in any direction, and is impelled forwards
by the breeze: two other arms serve as rudders to direct the course.
The animal first raises itself to the surface of the sea by ejecting
a quantity of water; if danger occurs, it absorbs water, and thus, by
making itself heavier, sinks to the bottom. The species are few in
number.
[Sidenote: NAUTILUS. CONUS.]
"_Nautilus_, pearly sailor, has several characteristics of _Argonauta_;
but the former is concamerate, the latter without chambers in the
shell. The generic characters of _Nautilus_ are, shell univalve,
divided into several compartments, communicating with each other by an
aperture. _Nautilus pompilius_ is often cut through, or bisected, to
display the chambers of the shell. In the East, the shells are formed
into drinking-cups. Sometimes the outer coat of the shell is removed,
and the pearly surface finely carved. This genus, according to Linnæus,
consists of fifty-eight species, some of which are fossil. (Plate
6.)
"In the following genera we must pay particular attention to the
_aperture_ of the shell, which is a generic distinction in most
univalves.
[Illustration: Plate 6.]
"The first is _Conus_, a large and beautiful genus, including many rare
and valuable species. Shell univalve, turbinate, aperture effuse, or
having the lips separated by a sinus, linear, without teeth, pillar
smooth. In their natural state the shells are usually covered with an
epidermis; but will bear a brilliant polish. _C. textilis_, cloth of
gold, is valuable. _C. generalis_ is sometimes sold for twenty guineas.
The example on the table is _C. Ebræus_, or Hebrew cone. (Plate
6.) Species one hundred and fifty-five; not one British. The
greater number are brought from the Indian Ocean; some from the seas of
Africa and from the South Sea.
[Sidenote: CYPRÆA. BULLA.]
"The shells of the genus _Cypræa_, cowry, are general favourites: the
species are fifty-eight; one British, _C. pediculus_. _C. moneta_
(Plate 1) is very common. The generic characters are, shell
univalve, involute, obtuse, smooth; aperture linear, the whole length
of the shell; effuse at both ends, toothed on each side.
"Look carefully at those three shells: do you perceive much resemblance
between them? 'Not much, if any,' you reply, yet they are all of
the genus _Bulla_. Here is _B. lignaria_, _B. terebellum_, (see
Frontispiece,) and _B. naucum_. (Plate 6.) There are
other forms, as the _B. ovum_, _B. volva_, the first somewhat like a
cowry; but it is toothed only on one side of the aperture; the second
has two long beaks.
"This genus is confessedly ill-determined. _B. naucum_ and _B. ampulla_
are examples of the common characters of the genus. The species are
sixty-one.
[Sidenote: VOLUTA. BUCCINUM.]
"_Voluta_ is also a large genus, containing one hundred and eighty-six
species. Shell univalve, aperture without a beak, and somewhat effuse;
columella _plaited_. This latter character we meet with for the first
time. Here is the common _Voluta_. (Plate 6.) The genus has
been much diminished by forming other very striking genera out of
it, as I shall soon show you, under the names of _Mitres_, _Olives_,
_Gondolas_, &c. _Voluta musica_, the music-shell, is remarkable, and
not at all rare.
"_Buccinum_ is another large genus. The shell univalve, spiral,
gibbous; aperture ovate, ending in a canal turning to the _right_, with
a short beak; pillar-lip expanded. Species, one hundred and seventy-two.
"You must recollect that when the apex of the shell is turned
_downwards_ the canal turns to the right, when it is turned _upwards_
the canal will be to the left hand. My example is _Buccinum
reticulatum_, a very common species upon our own shores." (Plate
7.)
"Is not this genus reduced by other authors?' asked Charles.
"Greatly," replied Mr. Elliot: "you will meet with tuns, helmets,
harps, and needles. Species of the _Buccinum_ genus are found in the
African, American, Indian, European, and Southern oceans. Eighteen
occur upon our coasts.
[Sidenote: STROMBUS. MUREX.]
"_Strombus_ contains forty-four species. Shell univalve, spiral,
aperture much dilated, the lip expanding, ending in a canal inclining
towards the left.
"You must notice the sinus in the outer lip, near the base of the
shell. _Strombus gigas_, the West Indian conch, is very large. Some
species have the lip ending in claws. _Strombus pes-pelicani_, the
pelican's-foot, has four palmated claws: (Plate 7.) it is a
British shell. The city of Santa Cruz, in America, is paved with the
shells of _Strombus gigas_.
"The genus _Murex_ is both large and beautiful. Shell univalve, spiral;
aperture oval, ending in a straight canal.
"These shells are of very unequal form; their surfaces frequently
covered with spines, knobs, or foliations. Some are remarkable for
the great length of the beak, (Frontispiece,) such as the
woodcock, the snipe's-head, and Venus's-comb. The _Murex_ before you
is foliated. (Plate 7.) The species are one hundred and
seventy-one. Several are found on British coasts, but they are not
remarkable for beauty.
"The top-shell, _Trochus_, is univalve, conic, spiral; the aperture
either angular or rounded; columella oblique: some of the apertures
have a tooth-like projection. (Plate 7.) Species, one hundred
and thirty. Several kinds occur in Britain. New Zealand, Friendly
Isles, Red Sea, and most other seas, afford the various species. Two
of this genus have the power of collecting parts of shells and other
testaceous substances, which adhere strongly to the whorls of the
shell: it is called the Conchologist. The other, named Mineralogist,
is loaded with stones, pebbles, ores, &c. When heavily laden they are
considered rarities.
[Sidenote: TROCHUS. TURBO. HELIX.]
"There is a great similarity between the genera _Turbo_ and _Trochus_.
You must observe the generic distinction carefully. Shell univalve,
spiral; aperture contracted, orbicular, entire. The one hundred and
sixty-seven species have been much divided by other writers. The
golden-mouthed _Turbo_ is a very fine shell. This genus also contains
the common periwincle, an inhabitant of most European shores. Sailors
report that if the animal is seen creeping high up the rocks, it
foretells stormy weather. _Turbo muricatus_ is a pretty shell."
(Plate 7.)
"Now we can tell the next genus," said Lucy. "_Helix_, snail. But what
a number of different shapes, father, those shells have! they are not
all snails, I should think, that you have placed on the table."
[Illustration: Plate 7.]
"According to Linnæus they are all of the genus _Helix_, which contains
two hundred and sixty-seven species. Many kinds are land-shells; others
live in fresh water; few inhabit the sea.
"Shell univalve, spiral, brittle; aperture contracted, semi-lunar,
or roundish. The common snail is well-known to most persons. _Helix
nemoralis_, the wood-snail, is very pretty; sometimes it is pink, with
brown bands, or plain yellow, or yellowy banded with brown. (Plate
7.) The greater part of this genus consists of shells remarkable
for their thin, brittle, and semi-transparent substances.
[Sidenote: NERITA. HALIOTIS.]
"The _Nerìta_ genus is very pretty: (Plate 7.) the texture
of the shell is in general much thicker than that of _Helix_. The
shell is spiral, gibbous, pillar-lip transversely truncated, flattish.
Seventy-six species. _Nerìta polìta_ is a handsome species: those most
valued are from the South Sea.
"We have now lost sight of the pillar-lip, and in the genus _Haliòtis_
we find a flat, ear-shaped shell, the spire nearly hidden, the disk
perforated lengthways with pores. Species twenty-one. The animals that
inhabit the ear-shells fasten themselves so firmly to the surfaces of
rocks, that much force is needful to disengage them: during the fine
nights of summer, the animal feeds on the herbage that grows on the
sea-shore. The sea-ear from New Zealand, and that from California, are
superb shells of considerable size. The British species, _Haliòtis
tuberculàta_, is not uncommon. (Plate 8.)
Without a regular spire: 5 genera.
[Sidenote: PATELLA. DENTALIUM. SERPULA.]
"You are well acquainted with _Patella_, the limpet: one species of
this genus is very common on the rocks by the sea-side. (Plate
1.) In the _Patella_ genus we lose sight of a spire; the shell is
nearly conic, and shaped like a basin. The species are very numerous,
exhibiting great variety of form; the number is two hundred and forty.
"The form of _Dentalium_ is easily known. The shell is univalve, nearly
straight, tubular, not chambered, and open at both ends.
"The species called elephant's-tooth is slightly curved, the colour
green, (Plate 2.) It is found in the European and Indian
seas. There are only twenty-two species. _Dentalium entails_, the
dog's-tooth, is very common.
"The _Serpula_ genus is remarkable. The shells are tubular, frequently
closed at one end. They are often found in clusters, adhering to rocks,
stones, fuci, shells, &c.
"There is _Serpula triquetra_ upon a _pecten_, (Plate 8.)
[Sidenote: TEREDO. SABELLA.]
"From the appearance of this piece of timber you may form some idea of
the devastation committed by the _Teredo_, or ship-worm. (Plate
8.) The shell is tubular and flexuose; two valves at each end, and
penetrating through wood. There are four species.
[Illustration: Plate 8.]
"_Sabella_ is the last genus, and a very remarkable one. The species
are twenty-five, several of which are British, (Plate 8.)
"Shell tubular, formed of sandy and calcareous particles, agglutinated,
and inserted in a membranous sheath. _Sabella Belgica_ is found in
Britain. _S. chrysodon_ is found buried in sea-sand, often several
inches long; it is covered with fragments of shells, and so brittle
that it is not easy to obtain a complete specimen.
"We have now finished our Linnæan genera, and here we must pause for
the present. If you wish for any assistance in your study of the
thirty-six examples that I have given you, I shall be ready to afford
you both any help that lies in my limited power."
CHAPTER VI.
[Sidenote: SYSTEM OF LAMARCK.]
"Lucy and I have been collecting a variety of species," said Charles
to his father, "since our last lesson in conchology. We have also
seen several large collections of shells, one of which was arranged
according to Lamarck. I was much pleased with the new genera taken from
_Buccinum_, _Bulla_, _Turbo_, and others.
"We are desirous of gaining information on this new system, if you can
spare a little time to attend to us."
"Willingly," replied Mr. Elliot; "I anticipated such a request, and
have been making lists of the genera belonging to each system; so that,
upon meeting with a new genus, you may be able to ascertain with some
accuracy its place in the old arrangement.
"Lamarck founds his system upon the structure and form of the animals,
so far as they have been ascertained, and with which the exterior, or
shell, must necessarily coincide. The conchology occupies the three
last _classes_, and _one order_ of another class, in the well-known
work which I have before mentioned to you.
[Sidenote: ANNULARIA. SEDENTARIA.]
"To begin with the 3rd Order of the 9th Class:--
Class, _Annularia_. Order, _Sedentaria_, Annulated Worms.
Lamarck. Linnæus.
_Siliquaria_, taken from _Serpula_.
_Dentalium_, ---- _Dentalium_.
_Pectinaria_, ---- _Sabella_.
_Sabellaria_, ---- _Sabella_.
_Spirorbis_, }
_Serpula_, } ---- _Serpula_.
_Vermilia_, }
_Galeolaria._
_Magilus._
"There has been much variation in the opinions of naturalists
respecting the proper place of genus _Dentalium_. Cuvier, a very
celebrated writer, agreed nearly with Lamarck; but still more recently
it has been considered as nearest to a new genus, _Fissurella_,
(_Patella_.) The fossil-shells are found in London clay in great
numbers; in the marle at Folkstone, &c.
"_Spirorbis._ All the species are minute, fixed upon sea-weeds, and
other marine substances. The animal which inhabits them is of a deep
red colour.
"_Galeolaria_ is a New Holland genus.
"_Magillus_ is found in the Isle of France; the shell is sometimes
three feet in length.
* * * * *
[Sidenote: CIRRHIPEDA--FIRST ORDER.]
"Class 10th. _Cirrhipeda_, contains two orders: the first, _sessile_,
or placed upon some other body; the second, _pedunculate_, and fixed at
the extremity of the pedicle to other substances.
"The class takes its name from the _Cirrhi_, or feathery tentacula. The
genus _Lepas_ only is contained in the _Cirrhipeda_ class.
* * * * *
"1st Order. Shells Sessile.
Genera.
_Tubicinella._ }
_Coronula._ }
_Balanus._ }
_Acasta._ } All included in _Lepas_.
_Creusia._ }
_Pyrgoma._ }
"The first genus contains but one species; the shell is buried up to
its aperture in the skin and fat of whales.
"The second, _Coronula_, is found inserting itself in the sea-turtle,
&c.
"_Balanus_ is known to you as the acorn-shell; a genus widely diffused;
abounding on rocks, shells, and wood, in large colonies.
[Sidenote: CIRRHIPEDA--SECOND ORDER.]
"_Acasta_ is found upon sponge.
"For examples of _Creusia_, we must examine our _madrepores_, and other
corals; the shells of this genus are either affixed or buried in them.
"_Pyrgoma_ likewise adheres, or penetrates into corals.
"In the 'Penny Cyclopædia,' under the word _Cirrhipeda_, you will find
much useful information, and some plates that will give you a good idea
of this class. In the British Museum you may see many of the species,
and may thus make yourselves familiar with them.
* * * * *
"2nd Order. Shells pedunculated.
_Pentalasmis_, (_Anatifera_.) }
_Pollicipes_. } _Lepas._
_Cineras._ }
_Otion_, ear-barnacle. }
"We have already noticed _Pentalasmis_, or barnacle, (Plate
2.) The generic name is changed by later writers; so are those of
the two last.
"_Pollicipes_ resembles _Pentalasmis_, with a shorter pedicle, which
is rough. The natives of Goree are said to eat a large species of
_Pentalasmis_."
"I think we shall not fail to recollect the _Cirrhipeda_ class," said
Lucy; "the forms of the shells are remarkable: and those that live on
_Madrepores_ I shall search for immediately; but what a number of new
genera are taken from the single one of _Lepas_!"
[Sidenote: EXPLANATIONS.]
"Since the time of Linnæus," replied Mr. Elliot, "many more
observations have been made upon the shells that he had examined;
many new shells, both genera and species, have been found; and there
is little doubt that, if Linnæus had now been living, he would have
found his own genera inadequate, and would have established new ones.
I fear you will have to regret the opposite extreme, and complain of
the multiplicity of new genera, and new names. Our object is to become
familiar with the shells, and by knowing the Linnæan name, and that
bestowed by Lamarck, two authorities very generally cited, you may
understand what species is alluded to by modern conchologists. The
names of Bruguieres, Leach, Gray, and Sowerby will often occur among
many others.
"For example: let us take the plate of a remarkable multivalve; you
find that it is named _Scapellum vulgare_, and that it is so called
by Leach. Below, you find '_Pollicipes scapellum_, Lamarck;' and
on referring to our comparative lists we find that the shell was a
_Lepas_, (_L. scapellum_ of Linnæus.)"
[Sidenote: EXPLANATIONS.]
"But they have kept the specific name," observed Charles.
"And made it the generic," said Mr. Elliot; the peculiarities and
variations are deemed insufficient to found a new genus.
"Here we shall pause for the present; and then proceed to the 11th
Class."
CHAPTER VII.
Eleventh Class.--_Conchifera._
Two Orders.--1st. _Bimusculosa_, two muscular impressions.
2nd. _Unimusculosa_, one muscular impression.
[Sidenote: CONCHIFERA, SHELL-BEARERS.]
"This class," observed Mr. Elliot, "contains all the bivalves of
Linnæus, and some genera taken from the univalves and multivalves.
"The animals of this class are _shell-bearers_ or _carriers_, they
remain constantly fixed in their habitations: the body is fastened to
the shell by one or two strong muscles: when the shell is vacant we
find the _cicatrix_. Refer to your explanation of terms, and you will
find the word.
"The body is soft, without joints, without head or eyes; it is wrapped
in a mantle or tunic. The mouth, always hidden in the tunic, is merely
an opening to admit food, without jaws or teeth. The shell is always
bivalve; the valves united by a hinge or a ligament; sometimes there
are accessory pieces to the valves.
[Sidenote: CONCHIFERA. UNIMUSCULOSA.]
"Some of the _Conchifera_ are furnished with a kind of foot, which
enables them to move with their shells, to draw out fibres by which
they fasten themselves to marine bodies. The muscles that fasten the
animals to their shells are thick and strong; their use is, to close
the valves by contracting; when the muscle is relaxed, the elastic
ligament is sufficient to open them. The _Conchifera_ are all aquatic;
some inhabit fresh water, the others dwell in the sea.
"The class contains nineteen families and two orders. The first order,
_Bimusculosa_, contains thirteen families. The first includes genera
that you will scarcely expect to find among the bivalve shells.
* * * * *
"1st Family, _Tubicolaria_, contains,
_Aspergillum_, Watering-pot _Serpula._
_Clavagella_ -------
_Firtuluna_
_Septaria_ _Serpula._
_Teredina_ Fossil genus.
_Teredo_ _Teredo._
"_Aspergillum Javanum_ is a rare and curious shell from the Indian
seas, (Plate 9.) The whole family is remarkable, and was
referred, you perceive, to a very different order. _Clavagella_
was till lately considered as existing only in a fossil state. The
researches of recent travellers have discovered _Clavagella_ at Port
Jackson, in Australia.[A] There is a specimen in the British Museum.
The valves are enclosed in the tube.
[A] See Penny Cyclopædia, article Clavagella.
"The valves of _Teredo_ are noticed as forming part of the Linnæan
generic character, you will recollect. Lamarck considers them as true
_Conchifera_. In many specimens of _Teredo_ the valves are wanting, and
the tube only remains.
* * * * *
[Sidenote: PHOLADARIA.]
"The family _Pholadaria_ contains,
_Pholas._ _Pholas_, stone-piercer.
_Gastrochæna_ _Pholas_ and _Mya_.
"Notwithstanding the accessory pieces of the hinge, _Pholas_ is placed
among bivalve shells, the essential character of which is to have two
valves united by a hinge. The _Pholas_ has a foot or strong muscle,
very thick and short. In the next genus, composed of _Pholas hians_ and
_Mya dubia_ there are no secondary valves.
"Allied to this family is _Xylophaga dorsalis_, a curious shell. One
specimen has been lately found at Gravesend, upon a stick.
* * * * *
[Sidenote: SOLENACEA. MYARIA. MACTRACEA.]
"_Solenacea_ includes
_Solen_ _Solen._
_Panopæa_ _Mya._
_Glycimeris_ _Mya._
"The _Solen_ is furnished with a muscle, called by some writers a
tongue. By the aid of this instrument they descend two feet deep in the
sand. The tongue is first projected from the shell, and cuts a hole.
It then assumes the form of a hook, and draws down the shell into the
hole. This operation is repeated until the shell disappears. _Panopæa_
is a large shell--it is in the Museum.
* * * * *
"4th Family, _Myaria_.
_Mya_ _Mya_, or gaper.
_Anatina_ _Mya._
"The animal of _Mya_ has also a foot: it buries itself in the sand. You
know the broad tooth of the _Mya_ genus. _Anatina_ has a tooth on each
valve.
* * * * *
"Second Section contains four families.
"_Mactracea_ has the following genera:
_Lutraria_ _Mactra._
_Mactra_ _Mactra._
_Crassatella_ _Mactra_.
_Erycina_ ----
_Ungulina_ ----
_Solenomya_ _Mya_.
_Amphidesma_ _Tellìna_.
"_Crassatella_ is a genus from the seas of New Holland. The shell
is very thick, with a brown epidermis. A fossil species is found at
Hordwell cliff. There are several species also found in the chalk.
_Mactra_, _Lutraria_, and _Erycina_ are found in a fossil state.
_Crassatella sulcata_ is common in London clay.
* * * * *
[Sidenote: CORBULA. LITHOPHAGA.]
"The family _Corbula_ contains two genera.
_Corbula_ ----
_Pandora_ _Tellìna_.
"_Corbula_ comes chiefly from the Asiatic Seas. There is _one_ species,
formerly _Mya inequivalvis_, from the British Ocean; fossil species
several. _Pandora rostrata_ is British, and is said to be met with at
Weymouth. It is a pretty shell. The ligament of these is internal.
* * * * *
"_Lithophaga_ includes
_Saxicava_ _Mytilus_.
_Petricola_
_Venerupis_, or Venus of the rocks.
[Sidenote: VENERUPIS PERFORANS. PSAMMOBIA.]
"These genera consist mostly of small shells, inhabiting stones, into
which they bore holes. _S. rugosa_ is British. _Venerupis perforans_
is found on our coasts in stones. The valves of these shells have no
accessory pieces like _Pholas_.
* * * * *
"_Nymphacea_ is the next family, containing, in the first section,
_Sanguinolaria_ _Solen_.
_Psammobia_ _Tellina_.
_Psammotæa_ ----
"In the genus _Psammobia_ we find our _Tellina Feroensis_. (Plate
4.) The shells of this and the preceding genus resemble the solens
in a trifling degree, being a little open at the sides. In form they
are near _Tellina_, but have not the fold on the anterior valve, but an
angle on _each_ valve. The ligament is exterior.
* * * * *
"In the second section are--
_Tellina_ _Tellina_.
_Tellinides_ _Tellina_.
_Corbis_ _Venus_.
_Lucina_ _Venus_ and _Tellina_.
_Donax_ _Donax_.
_Capsa_ _Donax_.
_Crassina_ _Venus_.
[Sidenote: CORBIS. LUCINA. CAPSA. CYCLAS.]
"There is but one species of _Tellinides_ from the island of Timor. The
genus _Corbis_ is fossil, with one exception, _Corbis fimbriata_, from
the Indian Ocean. _Lucina_ is a pretty genus of shells. _L. carnaria_
is frequently found in collections. The interior of the valves is of a
deep red colour: the muscular impressions are very distant from each
other; one is greatly lengthened out; the valves delicately striated.
_Capsa_ is taken, you perceive, from _Donax_.
"_Tellina_ is found fossil on the borders of the Red Sea, also in the
county of York. Of _Donax_ and _Mactra_ the fossil species are few.
"In the third section of this order we find six families. 1st.
_Conchæ_, which are of two kinds, fluviatic, living in fresh-waters;
and marine, or living in the sea. Of the first are,
_Cyclas_, taken from _Tellina_.
_Cyrene_, partly from _Tellina_ and _Venus_.
_Galathea_, _Venus paradoxa_, (one species.)
"_Cyclas rivicola_ (Plate 9.) will give you an idea of this
genus: it is _Tellina cornea_ of Linnæus. The species are very common
in lakes, rivers, and ponds: it abounds in river-sand, from which you
may often procure perfect specimens. Lamarck observes that it is rare
in France; but appears common in the Thames.
[Illustration: Plate 9.]
[Sidenote: POTAMOPHILA. ASTARTE. PULLASTRA.]
"_Cyrene_ is a foreign genus.
"In the _Conchæ marìnæ_ the genera are very numerous. They are all
assembled under the _Venus_ of Linnæus. Lamarck reduced the genus; but
it has been yet further divided by later writers.
_Cyprina_, }
_Cytherea_, } From _Venus_, Lamarck's genera.
_Venus_, }
But _Pullastra_,
_Astarte_,
_Venerupes_,
and _Potamophila_ have been since withdrawn from the original genus.
* * * * *
"_Pullastra_ was the name of a species, and includes _V. pullastra_,
_V. papilionacea_, _V. decussata_, _V. litterata_, _V. virginea_.
"_Astarte_ includes some British species, _V. Scotica_, &c.
[Sidenote: VENUS. CYTHEREA. ISOCARDIA.]
"_Potamophila_ is a scarce river-shell from Ceylon. Some species
have also been brought from Congo by African travellers. The form
is triangular, very thick, covered with an olive-green epidermis.
Lamarck's two genera have been still further reduced; but I shall refer
you to the Museum for their new names. Observe, in _Venus_ there are
three cardinal teeth, close together, on each valve, with divergent
lateral teeth. _V. lamellata_ is rare and beautiful, from the seas of
New Holland. There are many species of _Venus_ in a fossil state. In
_Cytherea_ we find four cardinal teeth on the _right_ valve, three of
them near together, the fourth quite apart. The _left_ valve has three
cardinal teeth. _C. Dionè_, the thorny Venus, is a pretty shell with
spines. You may easily procure it.
"_Astarte_ has some fossil species in the crag and green sand: _A.
obliquata_ is one species.
"_Venericardia_ is wholly a fossil genus: one species is found in the
crag, _V. senilis_.
* * * * *
"The family _Cardiacea_ contains
_Cardium_ _Cockle_
_Cardita_ _Chama_ (some species.)
_Cypricardia_ ------
_Hiatella_ _Mya_.
_Isocardia_ _Chama_.
"_Isocardia cor_ is British. (Plate 9.) There is a beautiful
species, _Isocardia moltkiana_ from the East Indies, which is much
valued by collectors.
* * * * *
"In the family _Arcacea_ we find,
_Cucullea_ _Arca_.
_Arca_ _Arca_, ark-shell.
_Pectunculus_ _Arca_.
_Nucula_ _Arca_.
[Sidenote: ARCA. PECTUNCULUS. NUCULA. NAYADA.]
"The hinge of _Arca_ in this arrangement is always _straight_,
furnished with a number of teeth; the ligament is external. The shells
are open at one end, for the animal throws out at the aperture a number
of threads, by which it fastens itself to the rocks. The species are
thirty-seven, and also several fossil.
"The orbicular form of _Pectunculus_, and its arched hinge, distinguish
this genus from the preceding one. They are allied to the Pectens by
their form, and their crenulated internal margin.
"The hinge of _Nucula_ is set with little teeth on each side, like a
comb. It is pearly within, and sometimes small pearls are found in the
shell. _Pectunculus costatus_ is found in London clay.
"_Trigoniana_ is a small family containing _Trigonia_ and _Castalia_.
The first is a fossil genus chiefly. Some species are found in the
Portland stone, or oölite beds.
"The next family contains the _Nayada_, chiefly composed of fluviatic,
or fresh-water shells. They are covered with an olive-brown epidermis,
which is constantly found eroded, or destroyed at the beaks. The
muscular impressions are lateral and much separated; one of them is
formed of two or three distinct irregular impressions.
_Unio_, taken chiefly from _Mya_.
_Hyria_ _Mya_.
_Anodon_ _Mytilus_.
_Iridina_ Very rare genus.
[Sidenote: UNIO. ANODON. DICERAS.]
"_Unio_ has two teeth on each valve; one is cardinal, the other
lengthened out. The ligament is exterior--the shell pearly. _Unio
pictorum_ is common in rivers. The shell is used to hold small masses
of gold or silver for artists, under the name of _shell-gold_.
"_Anodon_ is also to be met with in our rivers.
"_A. anatina_ is eaten by ducks and crows. The latter, when the shell
proves too hard to penetrate, mount with it into the air, and letting
it fall, pick out the fish from the broken shell.
* * * * *
"_Chamacea_ has only three genera.
_Diceras._
_Chama_ _Chama_.
_Etheria_, a rare genus, from the Indies and Madagascar.
* * * * *
"_Diceras_ is a fossil genus--only two species known according to
Lamarck.
[Sidenote: CHAMA.]
"Linnæus had assembled in his genus, _Chama_, shells with equal and
with unequal valves, shells fixed to other marine bodies, with those
that are free; some with _one_, others with _two_ muscular impressions.
In the present genus, _Chama_, the shells are irregular, thick, scaly,
or spinous. The hinge has one thick tooth, often notched: the beaks are
bent inwards. They are found in the Indian, American, and Mediterranean
seas. There are several fossil species.
"The first order, _Bimusculosa_, is finished. In our next lesson we
shall proceed to the families and genera contained in the second,
_Unimusculosa_."
CHAPTER VIII.
[Sidenote: UNIMUSCULOSA. TRIDACNA. MODIOLA.]
Class.--_Conchifera._
Second Order.--_Unimusculosa._
"1st family, _Tridacnacea_.
_Tridacna_ _Chama_.
_Hippopus_ _Chama_, (one species.)
"In the first genus we find the great _Tridacna gigas_, the largest and
heaviest shell yet known. It sometimes weighs five hundred pounds. The
hinge has two teeth, the lunula is open, the valves equal, the ligament
exterior.
* * * * *
"_Mytilacea._
_Modiola_ _Mytilus_.
_Mytilus_ _Mytilus_.
_Pinna_ _Pinna_.
"The greater part of these genera attach themselves to marine
substances by a byssus. The _Modiola_ genus are rarely found fixed. The
ligament internal, lodged in a marginal gutter. Beaks nearly lateral;
hinge without teeth. The genus _Pinna_ is unaltered. Small crustaceous
bodies, resembling the crab, are sometimes found in the shells of the
_Pinna_.
* * * * *
[Sidenote: PINNA. PERNA. AVICULA.]
"_Malleacea._
_Crenatula_ Rare and little known.
_Perna_ _Ostrea_.
_Malleus_ _Ostrea_, hammer-oyster.
_Avicula_ _Mytilus_.
_Meleagrina_ _Mytilus_.
"The first genus is found in the seas of warm climates. The shells are
thin and foliated. The hinge of _Perna_ differs widely from that of the
oyster. It is linear, formed of sulcated teeth. There is a sinus under
the extremity of the hinge, for the passage of the byssus. Compare _P.
isognomon_ with the common oyster, and you will find few points of
resemblance between them. (Plate 5.) _Perna ephippium_ is also
a curious species, very pearly within. The _hammers_ are rugged and
singular in form. They are all foreign, from the oriental seas.
"_Avicula_, or Swallow, so called from the resemblance of the shells to
a bird flying, was considered as a single species by Linnæus. Lamarck
makes eighteen species in his new genera. _Meleagrina_ has two species.
The pearl-bearing muscle, as it is called, is found in the Persian
Gulf, the Gulf of Mexico, &c. The interior of the shell is coated with
thick pearl, and within it are formed those globular substances known
by the name of pearls.
* * * * *
[Sidenote: MELEAGRINA. LIMA. PECTEN.]
"Family, _Pectenida_: genera--
_Pedum_ Only species, from India, rare.
_Lima_ _Ostrea_.
_Plagiostoma._
_Pecten_ _Ostrea_, scallop.
_Plicatula_ _Spondylus_.
_Spondylus_ _Spondylus_, thorny-oyster.
_Podopsis._
"The genus _Lima_ is longitudinal, auricled, or eared; hinge without
teeth, with a hollow receiving the ligament. These are very pretty
shells, generally white, almost transparent, resembling the _Pecten_.
_Lima_ comes from the American seas, and is a species easily obtained.
There are also several fossil species.
"_Plagiostoma_ is wholly a fossil genus, of which several species are
found in this country, in lias, &c.
"The pectens are so easily known that I need only mention some fine
species, such as _P. pallium_, a splendid shell, from the Indian seas:
_P. pleuronectes_ is a finely polished, smooth species from the Indian
Ocean.
"The genus is divided into sections, viz. ears equal, ears unequal. You
may find some common species on our own shores, and you may procure
fossil species: they are numerous.
[Sidenote: PLICATULA. OSTREA.]
"_Plicatula_ is a genus taken from _Spondylus_. _Spondylus gæderopus_,
from the Mediterranean, is a common shell in collections.
"_Podopsis_ is a fossil genus.
"_Ostracea._
"The oysters and pectens differ so widely that they do not even rank in
the same family.
* * * * *
"In the _Ostracea_ are,
_Gryphæa_ _Ostrea_.
_Ostrea_ The same.
_Vulsella._
_Placuna_ _Anomia_.
_Anomia_ The same--Antique lamp.
"There is but one recent species of the first genus; but many fossil.
"The oyster is said to possess the most limited faculties of all
shelly tribes. Immovable upon the rock or marine substance to which
it is fastened, it receives no other nourishment than what the waves
contribute, and indicates no other sign of life than opening and
closing the valve of the shell. This genus still retains a great number
of species: one section has the margin of the shell either _simple_,
or _waved_, the other _folded_. _O. edulis_, common oyster, belongs to
the first division.
"_O. folium_ is of the second; a curious species, from the Indian and
American seas: the shell is fixed to wood and to the roots of trees on
the sea-shores.
"_Vulsella_ is a foreign genus, from the Indian and other seas.
[Sidenote: PLACUNA. ANOMIA.]
"_Placuna_ does not adhere to any marine substance. The valves are
flat, thin, and transparent; the very small space between them shows
that the animal must be extremely flattened: there are two singular
ribs at the hinge in the form of a V.
"_P. placenta_, Chinese window-glass, is so transparent when young,
that it serves instead of that material in China.
"_Anomia._ The shells of this genus are fixed, like the oyster, to
marine bodies. They live and perish on the spot where they are at first
produced. I have noticed the muscle by which they attach themselves.
Lamarck informs us that a hard, small operculum is to be seen at the
extremity of this muscle, and fills up the _hole in the flat valve_
when the muscle is contracted. (Plate 5.)
"The family _Rudista_ contains only a few genera, which will be quite
uninteresting to you at present.
"The next, _Brachiopoda_, has
_Crania._
_Orbicula_ _Patella_.
_Terebratula_ Some from _Anomia_.
_Lingula_ _Patella_."
Lucy could not forbear interrupting her father upon hearing the name
of _Patella_. "How can that genus be mixed with the _Conchifera_?" she
inquired.
"The shell is _bivalve_," he replied; "raised upon a fleshy peduncle,
and fixed to marine substances; the hinge is without teeth, having the
form of a duck's beak; the colour a greenish tint. It is found near the
Molucca isles.
[Sidenote: HIPPONYX MITRATA.]
"Yet more remarkable is the _Hipponyx mitrata_, a common shell, known
as _Patella mitrata_, long supposed to be a univalve, the upper valve
only being known. A French naturalist discovered the lower valve, and
_both_ have one muscular impression in the form of a horse-shoe.
"I think that it will be best to pause a little before we enter upon
the study of the twelfth class, _Mollusca_, which contains most of the
univalves of Linnæus."
CHAPTER IX.
[Sidenote: MOLLUSCA. CLEODORA.]
Twelfth Class--_Mollusca._
"As I have observed that you have been very diligent in studying
Lamarck since our last lesson," said Mr. Elliot, "I propose to make you
acquainted with the variations in the univalve genera.
"The animals of the _Mollusca_ are soft, without joints, generally
possessing a head, eyes, and tentacula, or feelers. They have also
a fleshy membrane, called a foot, which they use for climbing. The
orders, excepting the first, are named from the position of this foot.
They are five in number. The first order contains very few genera. One
genus, named _Cleodora_, contains a species brought from Africa. The
shell is curious, transparent, and shaped like the head of a halberd.
"The animals of the second order, _Gasteropoda_, have a muscular
foot, or disk, on which they rest. The families are seven. The first,
_Tritonia_, I shall pass over.
"_Phyllidiana_ includes the genera--
_Phyllidia._
_Chitonella._
_Chiton_ Coat of mail.
_Patella_ _Patella_, or limpet.
[Sidenote: CHITON. PATELLA.]
"The _Chiton_ moves like the _Patella_, upon a disk, or foot.
"The body of _Patella_ is entirely covered by the shell. You may have
many opportunities of examining the British species. _P. pellucida_ is
very transparent, with blue lines.
* * * * *
"The family _Semi-phyllidiana_ contains
_Pleurobranchus._
_Umbella_ _Patella_.
"The _Umbella_ shell is flat and white, and is sometimes four inches in
diameter. It is common in the Isle of France: there is another from the
Mediterranean.
* * * * *
"_Calyptracea_ is a larger family: it has many genera taken from
_Patella_:
_Parmorphorus_, Thracian-shield.
_Emarginula_, }
_Fissurella_, }
_Pileopsis_, } _Patella_.
_Calyptræa_, }
_Crepidula_, }
_Ancylus_, }
[Sidenote: FISSURELLA. PILEOPSIS. BULLA.]
_Parmophorus_ is found in the seas of New Holland and New Zealand.
The margin of the next genus is distinguished by a slit: the shell
is conic. (Plate 3.) _Fissurella_ has the top of the shell
perforated; it is called the _key-hole_ limpet, from the shape of the
aperture. _Pileopsis_ is obliquely conic. It was with this division
that the curious _Hipponyx_ ranked.
"_Calyptræa_ is very thin and brittle, with an internal lip. (See
Frontispiece.)
"_Crepidula_ has the shell partly covered, or arched: it looks like a
little slipper.
"_Ancylus spina-rosa_ is a pretty species from the south of France: the
genus is fluviatic. _A. lacustris_ and _fluviatilis_ are both natives
of our fresh-waters.
* * * * *
"The next family, _Bullæana_, has
_Acera_ _Bulla_.
_Bullæa_ _Bulla_.
_Bulla_ The same.
"_Acera_ and the following genus have each but one species, _Bulla
carnosa_ and _B. aperta_ of Linnæus. The original genus _Bulla_ was
composed of an assemblage of shells of various characters, having
little resemblance except in their gibbous form. _Bulla naucum_ is an
example of the genus of Lamarck's system; so is _B. lignaria_. (See
Frontispiece.) _B. ampulla_ and _B. striata_ are common in
collections.
* * * * *
[Sidenote: APLYSIA. DOLABELLA.]
"_Aplysiana_ is a small family, containing
_Aplysia_, or Sea-hare.
_Dolabella._
"One species of _Aplysia_ is found on the Devonshire coast: the name
Sea-hare marks the singularity of the two tentacula, which resemble the
ears of the hare. The body is folded up in a loose skin, or mantle:
upon the middle of the back it carries a circular shield, thin,
transparent, and yellowish, in which it resembles the slug. These
animals swim with ease.
"_Dolabella_ resembles the _Aplysia_ in some degree; the genus is
foreign, and one species is known to inhabit the bays of the Isle of
France, where it covers itself with a portion of mud."
"I cannot understand why animals related to the slugs should find a
place here," said Charles.
"Have not slugs the characteristics of the _Mollusca_ class?" asked his
father. "And are you quite sure that they are without a shell?
[Sidenote: ONCHIDIUM. LIMAX.]
"Our next family, the _Limacina_, has
_Onchidium._
_Parmacella._
_Limax_, slug.
_Testacella._
_Vitrina._
"_Onchidium_ is a genus from the shores of the Indian seas. The animals
have a shield: they live near the sea, and some are known to swim,
often coming to the surface to breathe the air.
"_Parmacella_ was found by an English traveller in Mesopotamia. It has
a shell covered by a shield. But you have not answered my question
respecting the _Limax_, or slug."
"I do not recollect," replied Charles; "yet how often we see slugs!"
"If I may be allowed to answer," said Lucy, "I think that the slug has
what I now understand to be a _shield_. I have often watched the animal
contract itself, and seen a broad, flat piece upon the back, which I
thought was a kind of shelter for it."
"The _Limax_, or slug," continued Mr. Elliot, "is, in fact, provided
with a coriaceous escutcheon, or shield, beneath which the animal
partly conceals itself. The _Limax agrestis_, or spinning-slug, has the
power of suspending itself by a kind of thread, formed of the viscid
substance that covers the body.
[Sidenote: TESTACELLUS. COLIMACEA.]
"_Testacellus_ is a very interesting genus, lately found in England:
the animal has a resemblance to the common slug: it carries the shield
on the hinder part of the body.
"_Testacellus scutellum_ feeds on earth-worms, and can so much lengthen
the body that it follows them under-ground.
"Our next order will show great alterations in the very large genus
_Helix_. I shall name to you those of Lamarck.
"The third order of _Mollusca_, _Trachelipoda_, begins with a
well-known genus, the snail, _Helix_. The term signifies that the
_foot_ is situated under the neck, or anterior part of the body.
The families in this order are numerous: they are divided into two
sections; the first includes those that breathe only in the air; the
second those that can exist only in the water, and are furnished with a
syphon.
* * * * *
[Sidenote: HELIX. CUROCOLLA. ANOSTOMA.]
"First section: family _Colimacea_; genera numerous; animals live
upon land only; tentacula generally four; during winter they enclose
themselves in their shells, with a false operculum.
_Helix_, snail _Helix_.
_Carocolla_ _Helix_.
_Anostoma_ _Helix_.
_Helicina_ _Helix_.
_Pupa_ _Helix_.
_Clausilia_ _Helix_.
_Bulimus_ _Helix_.
_Achatina._
_Succinea_ _Helix_.
_Auricula_ _Voluta_.
_Cyclostoma._
"What a number of new genera!" said Lucy. "I see the forms of the
shells vary very much; and how beautiful these little transparent
shells are!"
"They will find a place shortly. Here is a well-known species, _H.
aspersa_, in most of its varieties; _H. pomatia_, the apple-snail, now
naturalized in the county of Surrey; _H. ericetorum_, white with brown
bands, very frequent on chalky soils; _H. citrina_, transparent, pale
yellow, sometimes with one dark band; _H. muralis_, from the walls of
Rome; _H. bidentalis_, from Teneriffe; and the little _Helix hispida_,
which you may search for in your own garden; it is small, dark brown,
and rough.
"_Carocolla_ has the shells more flattened than _Helix_.
"_Anostoma depressa_ is a rare and curious shell.
"_Helicina_ is a West Indian genus. You saw them just now. We shall
find Helix in two other families.
[Sidenote: PUPA. BULIMUS. AURICULA.]
"_Pupa_ is a curious genus. The shells resemble a chrysalis. A few
minute species are found in Britain. _P. muscorum_ I have found buried
among damp moss. The larger species are natives of tropical regions.
These shells are often found _decollated_.
"_Clausilia papillaris_ is a pretty shell. (Plate 9.)
"_Clausilia rugosa_ is found in some parts of Britain, under old
hedges, at the foot of old trees, and similar places. It is a tapering
shell, with the aperture reversed, or left-handed, and bi-dentated:
the colour red-brown. It is to be found in the vicinity of Dorking, in
Surrey.
"_Bulimus_ is a large genus. A common small species is the _Gaudaloupe
Bulimus_.
"The largest land-shells are found in the genus _Achatina_. The greater
number are African.
"_Succinea_ contains a few species. One of them, _S. amphibia_, is
common near fresh-water.
"_Auricula_ has some resemblance to a _Voluta_. The aperture is
longitudinal: the columella has one or more folds.
"The forms of the species in _Cyclostoma_ are variable; but the
aperture is circular, and the margin revolute, or rolled back. _C.
elegans_ is often to be found on hedge-banks or chalk soils. It is a
pretty shell, sometimes white, often tinted with purple.
"In the family _Lymænana_, the species are amphibious; inhabiting
fresh-water; but rising to the surface to breathe the air. They have
but two tentacula.
"As several species are British, you may have the satisfaction of
examining them for yourselves.
* * * * *
[Sidenote: PLANORBIS.]
"The genera are,
_Planorbis_ _Helix_.
_Physa_ _Bulla_.
_Lymnæa_ _Helix_.
"_Planorbis_ is a discoid shell, and one peculiarity of the genus is,
that they are all reverse shells. In a discoid shell the spire is
depressed; when held up, the whorls turn from right to left, and the
aperture is left-handed. The largest species is _P. cornu-arietis_,[B]
which is a native of Brazil. _P. corneus_ is common in ponds and
ditches. Empty shells are to be found at the edge of the water.
(Plate 9.) If you take the animal to examine, and study its
habits, remember that you have no right to injure it, and that you have
already promised me that no kind of cruelty shall take place.
[B] Ram's-horn.
"_P. vortex_ is a smaller species. The outer valve is carinated.
"_Physa_ is found in fresh-water upon aquatic plants. They are small
shells.
[Sidenote: LYMNÆA. MELANOPSIS. VALVATA.]
"The animal of the _Lymnæa_ genus has two flat tentacula. _L.
stagnalis_ is a very pretty spiral shell, common in ponds.
"_L. auricularia_ is also frequent. It is much smaller than the first
species. The last whorl is swelling, and the aperture very wide. They
are both thin and brittle.
* * * * *
"The family _Melaniana_ are chiefly foreign. The shells are covered
with a dark-coloured epidermis. They are operculated.
_Melania_ _Helix_.
_Melanopsis._
_Pirèna._
"A species of _Melanopsis_ inhabits the river Orontes, in Syria.
* * * * *
"There is yet another family connected with _Helix_, the _Peristomata_,
containing
_Valvata._
_Paludina_ _Helix_.
_Ampullaria_ _Helix_, partly.
[Sidenote: PALUDINA.]
"Some of the _Valvata_ genus are found in fresh-water in Britain and
other European countries. The shells are small; they are discoid or
conoid, and have an operculum. In the shells of this family the margin
of the aperture is carried completely round. In _Paludina_ the whorls
are convex. They generally inhabit fresh-waters.
"_P. vivipara_ is found in rivers. Quantities of empty shells may be
taken from the sand of the Thames.
"Fossil species abound--Petworth marble is full of them."
CHAPTER X.
[Sidenote: NERITACEA. NERITINA.]
"The family of the _Neritacea_," said Mr. Elliot, as he renewed his
lessons to Charles and Lucy, "are remarkable in their form. Their
left-margin is truncated, without any appearance of a columella. They
possess an operculum, and are either marine or fluviatic. The genera
are,
_Navicella._
_Neritìna_ _Nerìta_, Nerite, or hoof-shell.
_Nerìta_ _Nerìta_.
_Natìca_ _Nerìta_.
"You will recollect that the order _Trachelipoda_ is still continued.
"_Navicella_ is a foreign genus from the Indian rivers.
[Sidenote: NERITINA. NERITA.]
"_Neritìna_ is a pretty genus of shells, from the European, the East
and West Indian rivers. They resemble the _Nerìta_ genus, but are all
fresh-water shells; thin, smooth, and variously marked; without any
tooth or notch on the right-margin of the aperture.
"_N. virginea_ is common in collections; it is marked with various
lines and dots.
"_N. fluviatilis_ is common in our rivers: you may find plenty in
river-sand, of red and brown colours, and various sizes.
"_N. zebra_ and _N. meleagris_ are also pretty shells. The little
_Neritìna viridis_, from the West Indian streams, is one of the
smallest species, of a pale pellucid green.
"_Nerìta_ is a marine genus. The shells are solid and semi-globose; the
left-margin is truncated, the right-margin toothed, or crenulated. This
genus is never umbilicated.
"_N. polìta_ is a handsome shell: it is thick, polished, and variously
marked; the base of the aperture is yellowish.
"_N. peloronta_, the bleeding-Nerite, is marked with a crimson spot.
"_N. tessellata_ is sulcated, or furrowed, chequered with black and
white.
"_Natìca_ differs from the former genera in these particulars: the
shell is umbilicated; the left-margin oblique, not toothed, callous,
the callosity sometimes covering the umbilicus. The species are
numerous, and several are common in collections. "_N. aurantius_ and
_N. millepunctata_ are good shells.
[Sidenote: IANTHINA. SIGARETUS. STOMATELLA.]
"_Ianthina_ is the last of the snail-like genera. Its beautiful purple
colour renders the shell a favourite. They are marine, though so
fragile and transparent. The animal floats upon the surface of the
sea, by means of a vesicular appendage to the foot, which, it is
said, may be inflated or contracted at pleasure. _Ianthina_ shines by
night. _I. communis_ is found in abundance in the Atlantic and in the
Mediterranean.
* * * * *
"The family _Macrostoma_ contains,
_Sigaretus_ _Helix_?
_Stomatella._
_Stomatia._
_Haliòtis_ _Haliòtis_, sea-ear.
"These genera form a beautiful family, and all bear a resemblance to
the human ear.
"_Sigaretus_ is white and pearly; the shell is enveloped in the folds
of the mantle belonging to the animal. There are several species, one
or two of which were ranked among the _Helix_ race.
"_Stomatella_ is also very pretty; the shells are pearly. _S.
auricula_, from New Holland, has the appearance of a little _Haliòtis_.
"_Stomatia_ is a small genus.
[Sidenote: HALIOTIS. VERMETUS. SCALARIA.]
"With the genus _Haliòtis_ you are already acquainted. The animal
appears to be very elegantly formed, if the plate I have seen of it be
correct.
"There is a number of fine specimens in the British Museum.
* * * * *
"The family _Plicacea_ contains only,
_Tornatella_ _Voluta_, chiefly.
_Pyramidella._
"All the species have plaits, or folds, on the columella. The shells
are marine and foreign in both genera. (Plate 9.)
* * * * *
"Our next family, _Scalariana_, contains the genera
_Vermetus._
_Scalaria_ _Turbo_.
_Delphinula_ _Turbo_.
* * * * *
"The single species of the first genus, _Vermetus lumbricalis_,
inhabits the sea near to Senegal. The shell is tubular, thin, twisted
spirally; it is fixed on marine substances by the end of its thin,
pointed spire. The shells are usually found in groups.
"The genus _Scalaria_ is one of the most elegant among univalve shells.
The singularity of the numerous ribs renders the shells easily known
from all other genera of turreted _Mollusca_. The aperture is nearly
round, the whorls gibbous, or inflated with carinated ribs: the colour
is usually pink or white. It is very costly. (Plate 9.) These
shells are brought from the East Indies.
"The fossil species are very elegant: they are found in the strata
above the chalk.
"Two other species are common, _S. communis_ and _S. lamellosa_. The
first is a British species, and is called the _false Wentletrap_.
[Sidenote: DELPHINULA. SOLARIUM.]
"The shells of the genus _Delphinula_ are solid, thick, somewhat
discoid, often armed with spines, without any apparent columella. The
recent species inhabit the Indian Ocean. There are several fossil
species of _Delphinula_.
"The _Turbinacea_ family contains many genera, with which you will soon
become familiar. I believe you are already acquainted with this shell,
which, from the time it was first known to collectors, has always
been celebrated for beauty. It is now called _Solarium perspectivum_.
(Plate 9.) The large, spiral, crenated umbilicus is its great
peculiarity. The French call the shell _Cadran_, _dial_. In its natural
state the shell is covered with an epidermis. There are a few fossil
species, one in the oölite of our own country. The English name is
_staircase trochus_.
* * * * *
[Sidenote: ROTELLA. TROCHUS. TURBO.]
"The genera of _Turbinacea_ are,
_Solarium_ _Trochus_.
_Rotella_ _Trochus_--wheel-shell.
_Trochus_ _Trochus_--top shell.
_Monodonta._
_Turbo_ _Turbo_.
_Planaxis_ _Buccinum_.
_Phasianella_ _Turbo_.
_Turritella_ _Turbo_.
"The genus _Rotella_ contains small, flattened, wheel-shaped shells,
common in most collections. They are smooth and polished.
"_Trochus_ is still a large genus. _Trochus marmoràtus_ is a fine
species from the Indian Ocean. There are several handsome species
on our own shores. _T. magus_ is one of them; it has a large, deep
umbilicus, or perforation; the spire is flattened; the whorls are
crowned with tubercles. The _Trochi_ of tropical climates are thinner
than those of northern latitudes.
"When any of these shells are placed upon their _base_, their axis is
always inclined: of course they never stand perfectly upright.
"There are several fossil species.
"The genus _Monodonta_ holds a middle place between _Trochus_ and
_Turbo_, differing from the former in the aperture, and from the latter
in the columella, which is arched and truncated at the base. They are
all marine shells.
[Sidenote: LITORINA. TURBO. PHASIANELLA.]
"From the well-known genus _Turbo_, a new one has been formed, called
_Litorina_, which includes all the shells of our own coasts that
formerly ranked under _Turbo_. Consequently we find the periwincle
has changed its generic name, and from _Turbo_ it is altered into
_Litorina_. _T. muricata_ is now of the same new genus, _Litorina
muricata_. (Plate 7.)
"_Turbo pica_ is a large pearly shell known as the magpie. The
golden-mouthed _Turbo_ is very brilliant; the aperture appears as if
gilded, so fine is the yellow tint. It comes from the Molucca Isles.
_Turbo smaragdus_, from New Zealand, is a rare and beautiful species of
a bright green colour.
"_Phasianella_ is a beautiful genus of shells, formerly very costly.
A small but elegant species is found on our own shores, _P. pullus_,
_Turbo pullus_ of some authors. The colour is pink.
"_Phasianella bulimoides_, from New Holland, is the largest of the
species, and once a very rare shell.
"The term _Turritella_ will give you an idea of the form of our
last genus in the family _Turbinacea_. The shells are like _little
towers_, with a circular aperture. The older conchologists gave the
name of _screw_ to all turreted shells, without attending to the form
of the aperture. Hence we find screws among _Turbo_, _Buccinum_, and
_Strombus_ (spindle).
[Sidenote: TURRITELLA.]
"_Turritella duplicata_ is a heavy shell, often more than four inches
long. It is sulcated and carinated; the colour is yellow-white. _T.
bicingulata_ is white, marbled with yellow; the whorls are girded with
two ridges. There are several fossil species of this genus in London
clay."
"I think," said Lucy, "that three or four genera have been taken out of
_Turbo_--_Scalaria_, _Delphinula_, _Litoralia_, and _Turritella_, and
that _Litoralia_ is not Lamarck's genus."
"You are correct," replied her father, "and indeed so many alterations
are continually taking place in the generic names of shells, that I
cannot enter into all the niceties of modern conchologists. However,
the generic name of a shell, according to Linnæus or Lamarck, is
usually given, therefore I hope you will not be greatly at a loss upon
meeting with some apparently unknown genus."
CHAPTER XI.
[Sidenote: RANELLA. VOLUTA. OVULA.]
"What is Charles drawing from his pocket with a look of so much
importance," said Mr. Elliot, the next time they met.
"There is _Ranella crumena_, thorny-frog; _Ovula gibbosa_, the shuttle;
and _Voluta musica_, the music-shell," said Charles.
"Oh, who gave you those nice shells?" asked Lucy, "and how do you know
the names?"
"Let my father say if I am correct, first," replied Charles.
"Perfectly," answered his father; "but I fancy that I can guess how you
obtained your information. You have been buying these specimens, and
had the names from the shell-vender. I hope your purchase did not cost
much, for they are not rare shells?"
"No; I should not choose to spend a large sum, even from my purse,
until I am a better judge of the value of shells. But as our collection
is but small, I thought that Lucy would be glad to see an addition to
the stock."
[Sidenote: CANALIFERA, CERITHIUM.]
"Thank you, brother," said Lucy, "you never forget me in your
purchases or your pleasures."
"Let us return to our subject," said Mr. Elliot, "and notice the
families of the next section, which are all carnivorous, living on
animal substances. They have a projecting syphon, which conveys the
water to them: they are all marine. The syphon passes through the base
of the aperture, either into a canal, or channel, or a narrow, recurved
margin. The mouth is furnished with a trunk.
* * * * *
"_Canalifera_ contains in the first section,
_Cerithium_ Chiefly _Murex_.
_Pleurotoma_ _Murex_.
_Turbinella_ _Voluta_ and _Murex_.
_Cancellaria_ _Voluta_.
_Fasciolaria_ _Murex_.
_Fusus_ _Murex_.
_Pyrula_ _Murex_ and _Bulla_.
[Sidenote: FOSSIL CERITHIUM. TURBINELLA.]
"The naturalist Bruguieres established the fine genus _Cerithium_,
mixed by Linnæus among those of _Murex_, _Strombus_, and _Trochus_.
These shells are always turreted, having a short canal at the base;
the aperture oblong, oblique, with a gutter turned backwards.
(See Frontispiece.) Many are girded with zones, that are
granulated, or beset with little tubercles. It is remarkable that
_Cerithium giganteum_, a species more than a foot in length, is found
fossil in France, and as a living species in the seas of New Holland.
_C. telescopium_ is a fine shell from the East Indies. _C. vertagus_ is
smooth, tawny-white, with a recurved canal. It comes from the Moluccas.
Many species occur fossil in London clay and in plastic clay: the
Woolwich pits afford specimens, and also of _Turritella_.
"_Pleurotoma_, formerly united with _Murex_, is distinguished by the
singular _notch_ in the right-margin of the shell. One species, the
Tower of Babel, is well-known, and another is common under the name of
_Murex javanus_. The fossil species are numerous.
"_Turbinella_ is taken from _Murex_ and _Voluta_: some species are
thick, heavy shells, from the Indian seas.
"_Cancellaria_ is an elegant genus: the shells are varicose,
reticulated, or cancellated; the columella has folds upon it, varying
in number, the right-margin sulcated within. There are several fossil
species, which are considered very beautiful.
"_Fasciolaria trapezium_, the Persian robe, is a fine shell from the
Indian seas, very common in collections.
[Sidenote: FUSUS. PYRULA. RANELLA.]
"The genus _Fusus_ consists of spindle-shaped shells, of which _Fusus
colus_, the distaff, will give an idea. They are covered with an
epidermis which conceals, in some species, the fine colours beneath.
"_Fusus despectus_ (_Murex_ of Linnæus) is the largest of the British
turbinated shells, and very common: it is the large whelk.
"_Fusus contrarius_, the reverse whelk, is found fossil in the Essex
crag.
"Among the shells of the _Pyrula_ genus we find _P. ficus_, the fig,
placed by Linnæus among the _Bulla_ race. _P. spirillus_ is a pretty
species, with a long canal and a flattened spire, having a tubercle at
its termination.
* * * * *
"Second section of _Canalifera_: shells with a varix on the
right-margin.
_Struthiolaria_, }
_Ranella_, } _Murex_.
_Murex_, }
_Triton_, }
"_Struthiolaria_, ostrich-foot, is a remarkable shell from New Zealand.
"_Ranella_, thorny-frog, is frequent in collections: there are several
species: _R. crumena_ is easily obtained--you must purchase a specimen.
[Sidenote: MUREX. TRITON.]
"Notwithstanding the great reductions of the _Murex_ genus, it is
still large, and contains very fine species. The shells have _three
or more_ varices upon each whorl; those in _Ranella_ but _two_; while
_Struthiolaria_ has a varix only on the right-margin. The species are
numerous, and common in collections. _M. saxatilis_ is white, and zoned
with rose-colour or purple. The foliations, or branches, are erect. The
Rose-bush is pretty; and the wagtail, _M. motacilla_, will, doubtless,
be a favourite with you, as well as the scoop, _M. haustellum_.
"Notwithstanding the resemblance of the genus _Triton_ to those of
_Murex_ and _Ranella_, there are permanent differences which make them
distinguishable at first sight. I have already noticed the varices of
the preceding genera; in _Triton_ they never form longitudinal ranges,
but are alternate, few, and nearly solitary on each whorl of the spire;
these varices are generally smooth and without spines.[C] _Triton
variegatum_, the marine trumpet, is a large, handsome species, from the
Asiatic seas. _T. lampas_ and _T. lotorium_ are common. _Triton anus_
is very remarkable.
[C] Lamarck.
"In the next family, _Alata_, we must notice a remarkable fact: the
shells, while they are young, assume a different form to those more
advanced in growth.
[Sidenote: ROSTELLARIA. PTEROCERA. STROMBUS.]
"The genera are three--
_Rostellaria_, }
_Pterocera_, } _Strombus_, wing-shell.
_Strombus_, }
"In the first genus the shells are terminated below by a canal, or
pointed beak; the right-margin entire, or toothed, more or less
dilated with age, and having a sinus contiguous to the canal. There
is a specimen from our own coast, _Rostellaria pes-pelicani_, the
pelican's-foot: it was _Strombus_ of Linnæus. (Plate 7.) There
are many of this species found in a fossil state.
"The _Pterocera_ genus is easily known by the digitated, or fingered,
appearance of the right-margin. The greater part of the species become
very large. Here we find the scorpion, with seven digitations, from
India; the spider, with the same number, a large and fine shell, also
from India.
"_Strombus_ has a short canal, the right-margin dilated with age into
a simple wing, having, at the lower part, a sinus, separated from the
canal at the base of the shell.
"All the species are natives of hot climates; some attain a very large
size, such as _S. gigas_, so frequently seen in shops, and as ornaments
in a room. _S. gibbèrulus_ is a pretty little shell; the white, gibbous
whorls render it remarkable; the interior of the lip is pink. _S.
lineàtus_ has dark lines round the shell. _S. vittàtus_ has a very long
spire; the colour is tawny, girded with white: you may easily meet with
this species.
[Sidenote: CASSIDARIA. CASSIS.]
"The family _Purpurifera_ is composed of genera taken chiefly from the
large Linnæan genus _Buccinum_.
* * * * *
"It is thus divided:
"First, the genera with the canal ascending, or turned towards the back
of the shell--
_Cassidaria_, }
_Cassis_, } _Buccinum_, helmets.
"_Cassidaria_ is not a very common genus; but the helmets, _Cassis_,
are both numerous and plentiful in most collections. The straight
aperture slightly reminds you of a _Cypræa_ perhaps, but the short
canal, abruptly turned back, is a clear distinction; the right-margin
generally toothed; the columella folded, or wrinkled, transversely.
"_C. cornuta_, _C. flummea_, _C. arèola_ and _vibex_, are all
well-known species, _C. cornuta_ has large tubercles like horns round
the tip of the shell. _C. arèola_ is marked with chequers. _C. rufus_,
from the Moluccas, is a fine shell, with a deeply coloured red aperture.
"In the next division the canal is oblique, and directed backwards.
[Sidenote: NASSA. RICINULA. PURPURA.]
_Ricinula_ _Murex_.
_Purpura_, }
_Monoceros_, }
_Concholepas_, }
_Harpa_, } _Buccinum_.
_Dolium_, }
_Buccinum_, }
_Eburna_, }
_Terebra_, }
"To these genera another has been added, called _Nassa_, of which
_Buccinum arcularia_ will furnish an example. The columella has a
callosity very evident in the species _Pullus_ and _Thersites_.
"_Ricinula horrida_ has a ringent aperture of a fine violet colour; the
shell is thick, and covered with large black tubercles. The genus takes
its name from a resemblance to the seeds of _Ricinus_.
"_Purpura_ is a large genus: in certain of the species the
colouring-matter exists of which the ancients formed their famous
purple dye. It is the last genus that offers any appearance of a canal
at the base of the aperture.
"_P. patula_, the scoop, from the Atlantic and Mediterranean, has the
aperture remarkably dilated, the margin sulcated.
"_P. lapillus_ is a common British shell among the chalk-cliffs of the
coast; the colour varies, sometimes white, at others yellowish.
[Sidenote: MONOCEROS. CONCHOLEPAS. HARPA.]
"I shall describe a species of the singular genus _Monoceros_, by which
you will scarcely fail to recognise it.
"The columella is flattened like _Purpura patula_; just within the
outer lip is a row of small teeth; but the principal peculiarity is
a process, or horn, near the outer part of the lower lip, and close
to the canal, from which the genus derives its name _Monoceros_,
_one-horn_. It is brought from the seas of America.
"_Concholepas Peruviana_, the only species, is also a remarkable shell.
The aperture is very large, almost equal to the shell itself; the spire
is near the edge; the outside is marked with ribs, or costæ; there are
two short teeth on the right-margin. This shell was placed among the
_Patella_.
"The beautiful genus _Harpa_, harp-shell, is remarkable for its
elevated ridges on the back of the shell, its large aperture, and its
fine colouring. They are East Indian shells. _H. ventricosa_ is a
common species. _H. nobilis_ is very fine, and also _H. costata_.
"Equally well-known are the Tuns, _Dolium_, by their globose form,
the right-margin toothed, and a canal below. They reach a large size,
and are light shells in proportion to their bulk. _Dolium galeum_ is
sometimes the size of the human head. _D. perdix_ is a choice species.
[Sidenote: DOLIUM. BUCCINUM. EBURNA.]
"_Buccinum_ contains some British species, as _B. reticulatum_,
(Plate 7,) _B. anglicanum_, _B. undatum_, which is very
common. In connexion with this species I wish you to know that a marine
substance, called by sailors _sea-wash balls_, by others sea-sponge,
and extremely common on all our sea-coasts, is the egg-cases of the
_Buccinum undatum_. The mass is remarkably light, and composed of
numerous little cells, each of which has an opening. The colour varies
from yellow to white."
"I know them well," exclaimed Lucy, "how often I have asked the name of
those nests, but never could I obtain a reply worth having! And now,
father, give me leave to interrupt you a few minutes. What are those
black, stiff, marine substances, with a horn-like projection at each of
the four corners; they are all hollow, and open at each end, I think,
and usually inflated?"
"The egg-cases of the scate."
"Thank you, father, I will examine them again carefully when I am at
the sea-side."
"The genus _Eburna_," continued Mr. Elliot, "is remarkable from the
smoothness of the shells. _E. spirata_, the Joppa whelk, has the whorls
deeply channelled. (See the Frontispiece.) The columella is
umbilicated, and has a canal beneath it.
[Sidenote: TEREBRA. COLUMBELLA.]
"The _Terebra_ genus is turreted; very acute at the apex. (Plate
9.)
"The family _Collumellaria_ is next in order. The _canal_ now
disappears at the base of the shell, but there is a slope and folds on
the columella. We have reached the large genus _Voluta_ of Linnæus,
greatly reduced by withdrawing the following genera:
_Columbella_, }
_Mitra_, }
_Cymba_, }
_Melo_, } _Voluta_.
_Voluta_, }
_Marginella_, }
_Volvaria_, }
"The shells of _Columbella_ are of small size; two species are very
common in collections. _C. mercatoria_ is a little shell striated
transversely; the outer lip is thickened in the middle, and toothed;
the columella is plaited: the animal is furnished with an operculum.
"_Columbella nitida_ is another pretty species, smooth and shining: you
may perceive the generic marks if you look closely--two small folds on
the pillar-lip, and the swelling, toothed, outer margin. They are all
West Indian marine shells.
[Sidenote: MITRA. CYMBA. MELO.]
"_Mitra_ is a large genus, and it is believed that there are three
times as many species yet undescribed. The mitres are natives of warm
climates, and few are common. The pillar-lip of _Mitra_ is parallel,
with transverse folds; the base has a slope, but no canal; the margin
of the columella is thin and rolled back. _M. episcopalis_, the bishop,
is white with red spots; the columella-folds are four. (Plate
9.) _M. papalis_, the pope's-mitre, has five; the upper whorls are
broken into a kind of crown.
"In _Cymba_, the gondola, the spire ends in a tubercle, and scarcely
appears; the aperture is wide: they are very pretty shells.
"_Melo_, the melon, from the Indian Ocean, is a very fine genus; here
the spire is evident.
"_Voluta musica_ will serve as an example of the genus. The animal is
carnivorous.
"_Marginella_ is an oblong, smooth, and polished shell; its peculiar
character is the thickened outer lip; it is a neat, small species,
prettily coloured.
"_Volvaria_ is a cylindrical shell, convolute, the spire nearly hidden;
the aperture straight, as long as the shell. There is a fossil species
found in London clay. _V. monilis_ is sometimes strung for necklaces.
It comes from Senegal.
[Sidenote: OVULA.]
"The last family of the order _Trachelipoda_ is _Convoluta_, which
contains many very fine genera.
"They are the following:
_Ovula_ _Bulla_.
_Cypræa_ The same.
_Terebellum_ _Bulla_.
_Ancillaria._
_Oliva_ _Voluta_.
_Conus_ The same.
"The general characters of this family are the following:
"Shell without a canal, the base of the aperture sloping, or effuse,
the spire compressed, the last volution almost covering the rest.
"_Ovula_, you will recollect, was formerly confounded with the _Bulla_
genus: the form is egg-shaped, the outer lip toothed in one division,
smooth in the other; the shells are white and polished, particularly
_O. oviformis_, the poached-egg, from the Moluccas.
"_O. volva_, the weaver's-shuttle, is a rare and highly-valued species.
It is nearly globular in the middle, and is terminated at each
extremity by a long beak: it comes from the West Indies. _O. gibbosa_
is a common species; the shape is oblong, with a ridge in the centre.
[Sidenote: CYPRÆA. TRIVIA.]
"You can be at no loss on seeing the shells of _Cypræa_, a large and
beautiful genus, which remained unchanged for a long time. Lately, we
find a few of the small species are become a new genus, _Trivia_.
"The character of the _Cypræa_ is a longitudinal aperture, toothed, in
the adult state, on each side. The spire is scarcely to be seen.
"While the shells are young they have the appearance of a _Voluta_ or a
cone; the aperture spreads more, and is without teeth.
"The individuals of each species pass through three different states:
"In the first, the form is very imperfect; it is like a thin cone, and
shows no character of the genus; hence young students are perplexed if
they chance to have a young cowry in their collection.
"In the second state, the shell is still thin, with a _projecting_
spire; but attains its proper form.
"In the third, or adult state, the shell is thick, the colours are
perfected, and the spire is very nearly concealed.
"When the animal becomes too large for its habitation, it has the power
of leaving it, and forming a new one.[D]
[D] Lamarck.
[Sidenote: CYPRÆA.]
"The inhabitant of the _Cypræa_ shells has two tentacula of a
conic form, and finely pointed; the foot discous, and sometimes
tongue-shaped. The mantle is two-lobed, with wing-like margins, capable
of being turned back over the shell: this mantle preserves the shell
from injury when the animal issues forth in search of food. The genus
abounds both in the old and new world; but the larger kind chiefly in
warm climates. They live on the coast, and are generally found under
stones or rolled coral. A very few species are natives of the European
seas.
"The tiger-cowry is before you; a large and very common species in
collections; it also frequently adorns the mantel-piece. There is a
remarkable line extending along the back of the shell; at this part the
edges of the _mantle_, that I have before noticed, meet: this line is
conspicuous in many species.
"_C. aurora_ is a costly shell from Otaheite and New Zealand; the
colour orange, with the base and extremities white. It is large, and
has been sold for 60_l._ when a specimen has been obtained without any
perforation. The shell is worn by the New Zealand chiefs as a badge of
honour.
"_C. exanthema_ changes its appearance greatly as it advances in
growth. While young, three bands extend over the back, which in its
adult state disappear, and the fawn-coloured ground is spotted over
with numerous white circular marks.
[Sidenote: CYPRÆA.]
"_C. mauritania_, the moor, is a fine species, with very black sides,
and tawny-yellow back with spots. It is a native of Java.
"_C. caput-serpentis_, the serpent's-head, has dark sides, with white
fauces: the back is covered with net-work colouring: the fauces, you
must remember, are the narrow entrances at each end of the shell.
"_C. Isabella_, the orange-tip, with pale flesh-colour back, and the
fauces orange-colour.
"_C. Arabica_ is a common species in collections.
"_C. mappa_ is varied with deep brown or yellow lines and spots: the
dorsal line is laciniated.
"_C. talpa_, the mole, has the back fawn-colour, with three zones of
pale yellow; the base and sides sometimes nearly black. It comes from
Madagascar.
"_C. vitellus_, the fallow-deer, is fawn-colour, covered with small
white spots: from the Indian Ocean.
"The wasp, _C. asellus_, is white, with three brown bands.
"_C. helvola_, the star-cowry, has the sides dark orange; the
fawn-coloured back studded with small spots. It comes from the Maldives.
"_C. moneta_, the money-cowry, is generally white, sometimes yellow.
[Sidenote: TÆREBELLUM. OLIVA. TRIVIA.]
"_C. annulus_, the ring-cowry, has a yellow mark round the top of the
shell. The fowl-cowry, _C. moneta_, is used for money by the natives of
Siam and Bengal.
"_C. pediculus_ is changed to _Trivia_, a new sub-genus from _Cypræa_.
We find the following characters:--form of the columella internally
concave, ribbed; shell sub-globular, cross-ribbed. _T. carnea_,
flesh-coloured shell; thin, pure rose-coloured, with very thin, distant
ribs; lips whitish: it has sometimes an indistinct dorsal groove.
"_Trivia Europæa_ (_Cypræa_ of authors) is a globose shell, ash or
flesh-coloured, with three black dots and a whitish dorsal streak;
ribs close, rather thick, and whitish; base white; outer lip wide.
The variety has the back without spots. _T. pediculus_ has six
square dorsal spots; the colour of the shell pale red; ribs rather
thick-covered; dorsal line narrow; base reddish. Only one species, _C.
Europæa_ (or _Trivia_) is a native of our shores.
"There are several fossil species of _Cypræa_.
"We now pass on to a genus in which there is but one recent
species, _Terebellum subulatum_, _Bulla_ of Linnæus. (See
Frontispiece.) A fossil _Terebellum_ is found in London clay.
[Sidenote: ANCILLA. CONUS.]
"The _Oliva_ genus contains smooth, shining shells, common, and
therefore little valued; nevertheless they are beautiful, and of
various colours.
"The columella is obliquely striated; the aperture longitudinal and
straight. The olives were placed by Linnæus among the _Volutæ_,
on account of the striæ on the columella, without regard to the
peculiarity of the _canal_, by which the olives are known from all
other shells. This canal separates the _volutions_ of _Oliva_. Many
species are prettily marked by nature, others are rendered handsome by
polishing. _O. subulata_ is small, and pointed like a mitre. The common
olive is white, with brown, waved lines. _O. irrisans_ is ornamented
with yellow zigzag lines: it has two brown zones. _O. oriza_, the
little rice-olive, is white.
"I should have noticed the small genus _Ancilla_, formerly
_Ancillaria_, which is very near both to _Terebellum_ and _Oliva_.
The columella has a varix at the base, which distinguishes it from
_Terebellum_, and it wants the canal which separates the volutions of
_Oliva_.
"There are several fossil species.
"The concluding genus of the third order is very large, and contains
rare and costly shells. This is _Conus_, scarcely to be mistaken for
any other genus except _Voluta_, and that only at a first glance.
[Sidenote: CONUS.]
"The species are covered with an epidermis, sometimes very thick;
the spire has various degrees of elevation, sometimes almost flat;
the operculum very small and horny. They are natives of southern and
tropical seas: the animal is carnivorous: found in sandy mud, at
various depths of the ocean. The species are very numerous--Lamarck
makes 181 recent. Some new species have lately been discovered. Many of
the cones are very beautiful, both in shape and colour, and the genus
has been always in estimation among collectors. The _gloria-maris_,
_cedonulli_, _ammiralis_, and some others, have been sold at very high
prices, and some of the finest of these are now in England.
"Lamarck makes two divisions: in the first is comprehended the species
with coronated spires; the second those with simple spires; the latter
division contains far the greater number.
"Fossil cones occur, in London clay and crag, in England.
"No recent species are found upon our own coasts.
"_Conus Hebræus_, the Hebrew-cone, is easily known: (Plate 6:)
it has a white ground, and square black markings.
"_Conus virgo_ is white, with a purple base.
[Sidenote: CONUS.]
"_C. marmoreus_ is a fine shell. Numerous species are within reach
of your purses, and I do not doubt that you will soon acquire a good
collection at a moderate price. You, Charles, will find more pleasure
in a cone than in a top; and Lucy, who never found much pleasure in
toys except in taking them to pieces, has always a ready sixpence
either for a poor neighbour in distress, or for some harmless pleasure.
"We have yet two more orders of _Mollusca_ to notice, the _Cephalopoda_
and the _Heteropoda_.
"At our next lesson I shall mention the genera that are most likely to
come under your observation, either fossil or recent."
CHAPTER XII.
[Sidenote: ARGONAUTA. NAUTILUS.]
"So many families of the fourth order, _Cephalopoda_, are found only in
a fossil state, and which you will not easily meet with, that I shall
not consider it needful to give you the whole catalogue," observed Mr.
Elliot to his young pupils at the beginning of the next lesson.
"But we are exceedingly interested about fossils," replied Charles;
"pray do not pass any species that we may be likely to find."
"And I," said Lucy, "have much wished to ask whether the _snake-stone_
ever was a shell? it is something like a _Planorbis_, but heavy and
imperfect."
"I will answer your question presently," said her father. "Tell me what
genera remain to be noticed among the univalves of Linnæus?"
"_Argonauta_ and _Nautilus_," was the ready reply.
"The animals inhabiting these shells are _Cephalopoda_. The word
indicates the position of the feet, or more properly _arms_ of the
animal, which are ranged round the head like a crown. The body is
thick and fleshy, contained in a kind of bag, whence the head issues,
surrounded by these arms, which vary in different genera.
[Sidenote: CUTTLE-FISH. BELEMNITE. SPIRULA.]
"The common _cuttle-fish_, a native of our seas, will give you an idea
of a cephalopode.
"In the first family a fossil-shell occurs that is very frequently met
with.
"Family, _Orthocerata_; genus, _Belemnite_, thunder-stone, or
arrow-head. These fossil-shells occur abundantly in the chalk
formations. Many superstitious notions have been attached to this
extinct marine animal: of these you will find an account in the 'Penny
Cyclopædia.'
"In the family _Lituolita_ we meet with the delicate and remarkable
little shell _Spirula Peronii_, distinct from _Nautilus_ by the
separation of the volutions: it is nearly covered by the body of the
animal. The colour is white; the texture thin and brittle: it has a
lateral syphon, the orifice of which is very clearly to be seen as each
compartment is taken off. There is but one species; it is found in the
Southern Ocean and the Moluccas. The shells are seen floating on the
surface of the water when the animal is dead, and are sometimes carried
to the shore. (Plate 9.)
[Sidenote: AMMONITE. NAUTILUS.]
"Another family of this order, _Nautilacea_, contains, among many
other genera, the celebrated _Nautilus_. This genus, you are already
informed, is distinguished from _Argonauta_ by its shells being
many-chambered. Two or three fossil species have been found in London
clay.
"Among the various fossil-shells abounding in different strata, not
known in a recent state, the one most remarkable and frequently
occurring is the Ammonite, _Cornu Ammònis_, so called from the
resemblance it bears to the convoluted horns of Jupiter Ammon, in
mythological history. This is your _snake-stone_, Lucy, a local name,
which you had better change for Ammonite. Various legends are connected
with this fossil, of which you may obtain information by consulting the
before-mentioned publication.
"As you are desirous of studying geology, a knowledge of the Ammonites
is very requisite, since whole sections of the genus are characteristic
of certain strata.
"They are nearly allied to the _Nautilus_. The species are very
numerous; one hundred and twenty according to some authors--two hundred
and seventy species are enumerated by others. They occur in Europe,
Asia, and America: they have been found in the chalk with a diameter of
three feet.
"In the second division of this order the genus _Argonauta_ occurs:
the shell has been already described, and retains its original name.
(Plate 6.)
[Sidenote: OCTOPUS. LOLIGO. SEPIA.]
"In the third division is the family _Sepiaria_, containing _Octopus_,
_Lolìgo_, and _Sepia_. This section contains animals without shells.
_Octopus vulgàris_ is common in the European seas. In hot climates it
grows to a very large size. The animal has sufficient strength to draw
a boat under water.
"_Lolìgo_ also is found in our seas; the thin, transparent rib, called
the _dorsal blade_, you may probably find on the shore, the flesh that
covered the blade being cleared entirely from it. The colour is either
white or brown. It is called _sea-sleeve_.
"The bone of the cuttle-fish, _Sepia officinalis_, is so frequently
thrown on shore by the waves, that few persons visiting the sea-coast
can be ignorant of its form. You have a large collection there I see,
Lucy; and you are doubtless aware that this calcareous bone affords the
_pounce_ of the stationers, when finely pulverized: it also forms one
ingredient of tooth-powder.
"The ink of this marine animal is contained in a bag: the use of the
fluid is to colour the water around, in order to conceal itself from
hostile attack. The flesh of some of these animals is used for food,
and is frequently seen in the market at Naples. In the British isles it
is not put to any culinary purpose. The ink of _Sepia_ can be prepared
for a pigment, or paint.
"The fifth and last order of the twelfth class is _Heteropoda_, which
contains only a few genera, one of which I shall notice.
[Sidenote: CARINARIA.]
"_Carinaria_, the glass-nautilus, is a rare and very precious genus,
containing but three species. The first, _Carinaria ritrea_, has been
found in the Southern Ocean. There is a model of the shell in the
British Museum; that of Paris possesses the shell itself.
"_C. Mediterranea_ is found in the neighbourhood of Nice, and is
frequent in the summer months. So thin and delicate is the shell that
it is seldom found entire.
"The shell of _Carinaria_ is wholly external, and is attached to
the upper part of the body, apparently to protect the organs of
respiration. The body is transparent, dotted with elevated points; on
the lower part is a beautiful reticulated fin, of a reddish colour;
with the end of this fin it floats along, carrying its delicate shell.
The habit of the animal, which swims upon its back, reverses the
natural position of the shell, which is on the upper part of the body
when at rest."
"That is one of the most remarkable creatures you have yet mentioned,"
said Charles; "I may chance to meet with a specimen when I travel."
"Probably," replied Mr. Elliot; "but our lessons are now
concluded--_Carinaria_ is the last genus."
"How greatly we are obliged to you, father!" said Lucy: "but I hope you
will still give us a little advice and assistance: we shall often be
unable to determine the genera of some shells, I am sure, especially
among the bivalves."
[Sidenote: METHOD OF CLEANSING SHELLS.]
"Most willingly: but tell me if you know the easiest method of cleaning
shells when they become soiled, or when you purchase them in the
natural state?"
"That is a question I wished to ask."
"A little warm water and soap will cleanse and render them bright. Some
collectors rub Florence oil over their shells, which prevents them from
becoming dry. A weak solution of gum-arabic is sometimes applied, in
order to produce a polished and bright appearance.
"Nitric or muriatic acid, diluted, is used to take off the epidermis,
or any extraneous matter; but it must be done carefully, and the
shell plunged in water after the acid has been applied. But do not
make a practice of polishing; shells are best in their natural state,
generally speaking."
"Thank you, father!" said both the young people.
"You are welcome to any instruction I can give you," he replied; "and
now farewell for to-night."
A LIST OF SPECIES
_That may be purchased at a moderate Price._
Examples of the genera that may be easily obtained from the British
Coast, or which are expensive, are omitted.
_Dentalium entalis._
_Pectinaria Belgica._[E]
_Balanus tintinnabulum._
_Pentalasmis anatifera._
_Corbula nucleus._
_Psammobia virgata._
_Lucina carnaria._
_Cyprina Islandica._
_Cytherea chionè._
_Venus tigerina._
_Isocardia cor._
_Arca Noæ._
_Pectunculus marmoratus._
_Chama arcinella._
_Tridacna crocea._
_Pinna muricata._
_Perna ephippium._
_Meleagrina margaritacea._
_Lima squamosa._
_Spondylus gæderopus._
_Chiton squamosus._
_Emarginula fissura._
_Fissurella Græca._
_Pileopsis Hungarica._
_Calyptræa equestris._
_Bulla ampulla._
_Helix melanotragus._
_Pupa mummia._
_Bulimus ovatus._
_Achatina virginea._
_Neritina corona._
_Nerìta polìta._
_Natìca alba._
_Iànthina communis._
_Sigaretus haliotoideus._
_Pyramidèlla dolabrata._
_Scalària commùnis._
_Delphinula lacinìata._
_Solarium perspectivum._
_Trochus tuber._
_Monodonta labio._
_Turbo pica._
_Phasianella bulimoìdes._
_Cerithium vertagus._
_Pyrula ficus._
_Ranella crumèna._
_Murex haustèllum._
_Triton lotorium._
_Pterocera lambis._
_Strombus lineàtus._
_Cassis arèola._
_Ricinula horrida._
_Purpura patula._
_Monoceros imbricatum._
_Concholepas Peruvianus._
_Harpa ventricosa._
_Dolium maculàtum._
_Eburna spiràta._
_Terebra maculàta._
_Columbella mercatòria._
_Mitra episcopàlis._
_Voluta musica._
_Volraria monìlis._
_Ovula oviformis._
_Cypræa cribària._
_Terebellum subulàtum._
_Oliva utriculus._
_Conus virgo._
_Nautilus hians._
_Spirula Peronii._
[E] Or _Sabella_.
INDEX.
Page.
Acasta, 41
Acera, 64
Achatina, 69
Alata, 85
Ammonite, 103
Anatina, 47
Ancilla, 98
Ancylas, 64
Anodon, 54
Anomia, 29
Anostoma, 68
Annularia, 39
Aplysia, 65
Arca, 53
Argonauta, 29
Aspergillum, 45
Auricula, 69
Avicula, 57
Balanus, 40
Belemnite, 102
Bimusculosa, 44
Brachiopoda, 61
Buccinum, 32
Bulimus, 69
Bulla, 31
Calyptræa, 64
Cancellaria, 83
Capsa, 50
Caracolla, 68
Cardium, 23
Carinaria, 105
Cassis, 87
Cassidaria, 87
Cephalopoda, 101
Cerithium, 82
Chama, 26
Chamacea, 54
Chiton, 18
Cineras, 41
Cirrhipeda, 40
Clausilia, 69
Clavagella, 46
Cleodora, 62
Columbella, 91
Conchæ, 50
Conchifera, 44
Concholepas, 89
Conus, 30
Corbis, 50
Corbula, 48
Coronula, 40
Crassatella, 48
Crepidula, 64
Creusia, 41
Cyclas, 50
Cyclostoma, 69
Cymba, 92
Cypræa, 31
Cytherea, 52
Delphinula, 77
Dentalium, 36
Diceras, 54
Dolabella, 65
Dolium, 89
Donax, 23
Eburna, 90
Erycina, 48
Etheria, 54
Fasciolaria, 83
Fissurella, 64
Fusus, 84
Galeolaria, 40
Gasteropoda, 62
Gryphæa, 59
Haliotis, 35-75
Harpa, 89
Helix, 35-68
Heteropoda, 105
Hipponyx, 61
Ianthina, 74
Isocardia, 52
Lepas, 18
Lima, 58
Limax, 66
Lingula, 61
Litorina, 79
Loligo, 104
Lucina, 50
Lutraria, 48
Lymnæa, 71
Mactra, 23
Mactracea, 47
Magillus, 40
Melanopsis, 71
Meleagrina, 58
Melo, 92
Mitra, 92
Modiola, 56
Mollusca, 62
Monoceros, 89
Monodonta, 78
Murex, 35
Mya, 21
Myaria, 47
Mytilus, 27
Mytilacea, 56
Natica, 74
Navicella, 73
Nassa, 88
Nautilus, 30-103
Nerita, 35
Neritina, 73
Nucula, 53
Nymphacea, 49
Octopus, 104
Oliva, 98
Onchidium, 66
Orthocerata, 102
Ostrea, 26
Otion, 41
Ostracea, 59
Ovula, 93
Paludina, 72
Pandora, 48
Panopæa, 47
Parmacella, 66
Parmophorus, 64
Patella, 61-63
Pecten, 58
Pectunculus, 53
Perna, 57
Pentalasmis, 41
Phasianella, 79
Pileopsis, 64
Pinna, 57
Planorbis, 70
Placuna, 60
Plagiostoma, 58
Pleurotoma, 83
Plicatula, 59
Podopsis, 59
Pollicipes, 41
Potamophila, 51
Psammotæa, 49
Pterocera, 86
Pullastra, 51
Pupa, 69
Purpurifera, 87
Pyrgoma, 41
Pyrula, 84
Ranella, 84
Ricinula, 88
Rostellaria, 86
Rotella, 78
Rudista, 60
Sabella, 37
Scalaria, 76
Scapellum, 42
Serpula, 36
Sepia, 104
Siliquaria, 39
Sigaretus, 75
Solarium, 77
Solen, 22
Solenacea, 47
Spirorbis, 39
Spirula, 102
Spondylus, 25
Stomatia, 75
Stomatella, 75
Strombus, 33
Struthiolaria, 84
Succinea, 69
Tellina, 22-30
Terebellum, 97
Teredo, 46
Terebra, 91
Testacellus, 67
Trachelipoda, 67
Tridacna, 56
Trigoniana, 53
Trivia, 97
Triton, 85
Trochus, 78
Tubicinella, 40
Turbinella, 83
Turbo, 79
Umbrella, 63
Unio, 54
Unimusculosa, 56
Valvata, 71
Venus, 24-52
Venericardia, 52
Venerupis, 49
Vermetus, 76
Volvaria, 92
Voluta, 31
Vulsella, 60
Xylophaga, 46
THE END.
Joseph Rickerby, Printer, Sherbourn Lane.
* * * * *
Transcriber Notes
All illustrations were moved so as to not split paragraphs. Words with
accented vowels were not standardized.
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