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Title: Glimpses of Ocean Life - Rock-Pools and the Lessons they Teach
Author: Harper, John
Language: English
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'Natural History is the appointed handmaiden of Religion, enabling
us to feel and in some humble proportion to appreciate how closely
and how carefully the well-being and happiness of all creatures has
been provided for,--how admirably they are severally adapted to their
respective stations and employments, and how wonderfully every part
of their economy is made subservient to the general good. This is the
true spirit in which the aquarïst ought to work, and this is the end
and object of his science.'--_Rhymer Jones._
[Illustration:
1 & 2 Valves of PHOLAS SHELL
3 _Pholas crispata_, with siphons extended
4 COMMON BRITTLE STAR (_Ophiocoma rosula_) From Nature, showing the
progressive growth of new rays
5 COMMON CROSS-FISH (_Uraster rubens_)]
GLIMPSES OF OCEAN LIFE;
OR,
Rock-Pools and the Lessons they Teach.
BY
JOHN HARPER, F.R.S.S.A.
AUTHOR OF 'THE SEA-SIDE AND AQUARIUM,' ETC.
WITH NUMEROUS ILLUSTRATIONS BY THE AUTHOR.
'_Armado._ How hast thou purchased thy experience?
_Moth._ By my penny of observation.'
SHAKSPEARE.
LONDON:
T. NELSON AND SONS, PATERNOSTER ROW;
EDINBURGH; AND NEW YORK.
MDCCCLX.
TO THE RIGHT HONOURABLE
LORD BROUGHAM AND VAUX,
CHANCELLOR OF THE UNIVERSITY OF EDINBURGH,
ETC., ETC., ETC.,
THIS LITTLE VOLUME
Is Inscribed,
AS A TRIFLING TOKEN OF RESPECTFUL ADMIRATION
FOR
UNIVERSALLY RECOGNISED GREATNESS.
CONTENTS.
CHAPTER I.
ON THE PLEASURES DERIVED FROM THE STUDY OF MARINE ZOOLOGY.
Page
Introduction--Two classes of readers--Marine zoology
as an amusement--The botanist and his
pleasures--Entomological pursuits--Hidden marvels
of nature--The little Stickleback--Conclusion, 17
CHAPTER II.
A GLANCE AT THE INVISIBLE WORLD.
Microscopic studies--When to use the
microscope--Modern martyrs of science--Infusoria--Use
of Infusoria--Distinction between plants and
animals--_Vorticella_--_Rotatoria_--Wheel
animalcules--Mooring Thread of Vorticellæ--A
compound species of Vorticella described--_Zoothamnium
spirale_ of Mr. Gosse--Nature's scavengers, 27
CHAPTER III.
SEA ANEMONES.
Animal-flowers--_A. mesembryanthemum_--'Granny,'
Sir J. Dalyell's celebrated anemone--Original anecdote--_A.
troglodytes_--How to capture actiniæ--A roving 'mess.'--An
intelligent anemone--Diet of the actiniæ--Voracity of these
zoophytes--Defence of certain species--Actiniæ eating
crabs--Their reproductive powers--Size of the 'crass.'--The
Plumose anemone--Its powers of contraction, 45
CHAPTER IV.
EDIBLE CRAB--SHORE CRAB--SPIDER CRAB, ETC.
The Partane--Its character defended--Crustaceous demons--The
wolf and the lamb--Interesting anecdote--Reason and
instinct--Anecdote of the Shore crab--'The creature's run
awa''--A crustaceous performer--The Fiddler crab--A little
prodigal--Singular conduct of the Shore crab--The minute
Porcelain crab--_Maia squinado_--_Hyas
araneus_--_Maia_ and _C. mænas_--Anecdote--The
common Pea crab--Pinna and Pinnotheres--The Cray
fish--Masticatory organs of crabs--Fishing for
crabs--Crab fishers, 63
CHAPTER V.
HERMIT CRABS.
Enthusiastic students of nature--Aristocratic Hermit
crabs--Swammerdam--Hermit crab and its habits--Anecdote--The
Hermit in a fright--Soldier crab and Limpet--A crustaceous
Diogenes--Prometheus in the tank--The martyr Hermit
crab--The author's pet Blenny--Anecdote, 89
CHAPTER VI.
EXUVIATION OF CRUSTACEA (THE PHENOMENA OF CRABS, ETC.,
CASTING THEIR SHELLS).
The Tower of London--A crustaceous armory--The author's
experience on the subject--Reamur and Goldsmith--Rejected
shells of crabs--Anecdote--Hint to the young
aquarian--Exuviation described from personal observation
in several instances--Renewal of injured limbs--Frequency
of exuviation--Effect of diet on crustacea--Exuviation
arrested--Exuviation of the Hermit crab--How the process
is effected, 109
CHAPTER VII.
PRAWNS AND SHRIMPS.
Habits of the Prawn--The Common Shrimp--How to catch
shrimps--Conclusion, 135
CHAPTER VIII.
ACORN-BARNACLES--SHIP-BARNACLES.
The Common Barnacle described--Exuviation of the
_Balani_--Anecdote--The Ship Barnacle--Barnacle
Geese, 143
CHAPTER IX.
PHYLLODOCE LAMINOSA (THE LAMINATED NEREIS).
A rainy day at the sea-shore--Laminated Nereis--Its
tenacity of life--Its unsuitableness for the aquarium--How
the young annelids are produced--Evidence of a French
naturalist, 151
CHAPTER X.
THE FAN-AMPHITRITE.
Its renewal of mutilated organs--How to accommodate this
annelid in the tank--The 'case' of the
Fan-Amphitrite, 159
CHAPTER XI.
THE COMMON MUSSEL.
Dr. Johnson and Bozzy--Habits of the Mussel--Marine
'at homes'--The Purpura and its habits--Enemies of the
Mussel--Anecdote--Construction of the beard (or
Byssus)--Author's experience--Anecdote of the
mussel--Muscular action of its foot--Threads of the
beard--The bridge at Bideford--Anecdote--The
Mussel tenacious of life--The beard not poisonous--M.
Quatrefage--Mussel beds of Esnandes--Branchiæ of the
Mussel--Food of this bivalve, 163
CHAPTER XII.
TEREBELLA FIGULAS (THE POTTER).
Anecdote of the Potter--Its cephalic tentacula--Construction
of its tubular dwelling--_Terebella littoralis_--Curious
anecdote--Branchial organs of this annelid, 189
CHAPTER XIII.
ACALEPHÆ (MEDUSÆ, OR JELLY-FISH).
Introduction--Jelly-fish--Whales'
food--Lieutenant Maury--Appearance of the Greenland
Seas--Sir Walter Scott--The girdle of Venus--The
Beröe--_Pulmonigrade acalephæ_--Portuguese
man-of-war--_Hydra-tuba_--Alternation of
generations--Dr. Reid--_Modera-formosa_--_Cyanea
capillata_--Conclusion, 201
CHAPTER XIV.
DORIS EOLIS, ETC.
Anecdote--Young Dorides--Doris spawn--_Nudibranchiate
gasteropoda_--Dr. Darwin--Mr. Gosse--A black
Doris--_Bêches de mer_--A Chinese dinner--Bird's
nest soup, and Sea-slug stew, 221
CHAPTER XV.
THE CRAB AND THE DAINTY BEGGAR.
Anecdote--The Pholas and Shore-crab--The
_hyaline stylet_--The dainty beggar--The
gizzard of the Pholas--Of what use is the stylet? 233
CHAPTER XVI.
THE PHOLAS, ETC. (ROCK-BORERS).
Pholades at home--Habits of the Pholas--_P.
crispata_--The pedal organ--Finny gourmands--How is
the boring operation performed?--Various theories on
the subject--Mr Clark, Professor Owen--The Pholas at
work--The boring process described from personal
observation--Author's remarks on the subject--Pholas
in the tank--Conclusion, 241
CHAPTER XVII.
THE SEA-MOUSE.
The Sea-mouse--Bristles of the aphrodite--Its
beautiful plumage (?)--Its weapons
of defence--The spines described--Shape of the
aphrodite, &c., 263
CHAPTER XVIII.
STAR-FISHES, ETC.
The Coral polypes--The Lily-stars--St. Cuthbert's
beads--_Pentacrinus europæus_--Rosy feather star
_Ophiuridæ_--Brittle-stars--_Ophiocomo-rosula_--British
asteridæ--_Uraster rubens_--Habits of this species--Submarine
Dandos--Sir John Dalyell--Professor Jones--Star-fish feeding
on the oyster--Bird's foot Sea-star--_Luidia
fragillissima_--Cushion-stars--Professor Forbes, 269
CHAPTER XIX.
SEA-URCHINS.
Sea Urchins in the tank--Growth of the Echinus--Its
hedgehog-like spines--Suckers and pores--Ambulacral
tubes--Professor Agassiz--Movements of the
Echinus--_Pedicellariæ_--Masticatory
apparatus--Common Egg Urchin--_Echinus sphæra_--How
to remove the spines--'Do you boil your sea eggs?'--The
Green-pea Urchin--The Silky-spined Urchin--The Rosy-heart
Urchin, 287
CHAPTER XX.
THE SEA-CUCUMBER.
Its unattractive appearance out of water--Trepang--Several
varieties eaten by the Chinese--Common Sea Cucumber--Habits
of the Holothuriæ--Their self-mutilation and renewal of
lost parts, 301
CHAPTER XXI.
THE APLYSIA, OR SEA-HARE.
Anecdote--The Sea Hare plentiful at North Berwick--Its
powers of ejecting a purple fluid at certain times--Sea
Hares abhorred by the ancients--Professor Forbes--Spawn
of the Aplysia, 307
CHAPTER XXII.
SERPULÆ AND SABELLÆ.
Tubes of the _Serpulæ_--Dr. Darwin--The harbour
of Pernambuco--Its wonderful structure--Reproduction of
the _Serpulæ_--_Sabellæ_--Their sandy
tubes, &c., 313
CHAPTER XXIII.
THE SOLEN, OR RAZOR FISH.
How it burrows in the sand--How specimens are
caught--_Cum grano salis_--Bamboozling the Spout
Fish--Amateur naturalists, and fishermen at the
sea-shore, 321
CHAPTER XXIV.
A GOSSIP ON FISHES--INCLUDING THE ROCKLING, SMOOTH BLENNY,
GUNNEL FISH, GOBY, ETC.
Punch's address to the ocean--Old blue-jackets and the
'galyant' Nelson--The ocean and its inhabitants--Life
beneath the wave--Fishes the happiest of created
things--A fishy discourse by St. Antony of
Padua--Traveller's ne'er do lie?--The veracious
Abon-el-Cassim--Do fishes possess the sense of
hearing--Author's experience--An intelligent Pike
fish--Dr. Warwick--The Blenny in its native
haunts--A 'Little Dombey' fish--Anecdote--The
Viviparous Blenny--The Gunnel fish--Five-bearded
Rockling--Two-spotted Goby--Diminutive
Sucker-fish--Montagu's Sucker--The
Stickleback--Its nest-building habits
described--Conclusion, 327
CHAPTER XXV.
ON THE FORMATION OF MARINE AQUARIÆ, ETC.
Mimic oceans--Practical hints on marine
aquariæ--Various tanks described--The 'gravity
bubble'--Evaporated sea-water--Aquariæ in
France--Sea-water a contraband article across the
Channel--An aquarium on a fine summer's day--The
Lettuce Ulva--Author's tank--'Excavations on a
rocky shore'--Tank 'interiors'--Various centre
pieces--New siphon--Aquariæ difficult to keep in
hot weather--How to remove the opacity of the
tank--New scheme proposed--Conclusion, 353
LIST OF ILLUSTRATIONS.
No.
FRONTISPIECE, 1
COMPOUND VORTICELLÆ, 2
"GRANNY," Sir John Dalyell's celebrated Anemone, 3
A. TROGLODYTES, 4
A. CRASSICORNIS, 5
EDIBLE CRAB, 6
EDIBLE CRAB casting its Shell (from Nature), 7
SPIDER CRAB, 8
SHORE CRAB, 9
PORCELAIN CRAB, 10
HERMIT CRAB, 11
HERMIT CRAB in Shell of Large Whelk, 12
SHIP BARNACLES, 13
ACORN BARNACLES attached to Shell of the Limpet, 14
THE LIMPET, as seen from beneath, 15
LAMINATED NEREIS, 16
COMMON MUSSEL,--Shell open, 17
COMMON MUSSEL,--Shell closed, 18
THE BERÖE, 19
FAN AMPHITRITE, 20
TEREBELLA FIGULUS, 21
TEREBELLA LITTORALIS, 22
THE SEA-MOUSE, 23
DORIS, 24
YOUNG OF DORIS, 25
EOLIS, 26
THE PHOLAS, and Valves of its Shell, 27
THE BRITTLE STAR, 28
COMMON CROSS-FISH, 29
COMMON SUN-STAR (with 14 rays), 30
PURPLE-TIPPED SEA-URCHIN, 31
PURPLE-TIPPED SEA-URCHIN, Spine of, 32
PURPLE-TIPPED SEA-URCHIN, Suckers of, 33
THE APLYSIA, or SEA-HARE, 34
TEETH of the SEA-URCHIN (two views), 35
THE SEA-CUCUMBER, 36
SERPULÆ attached to piece of rock, 37
THE SOLEN, or RAZOR FISH, 38
THE BLENNY, 39
THE VIVIPAROUS BLENNY, 40
THE SPOTTED BLENNY, or GUNNEL-FISH, 41
THE MONTAGU SUCKER-FISH (three views), 42
THE MONTAGU SUCKER-FISH, Sucker of (magnified), 43
CHAPTER I.
INTRODUCTORY.
On the Pleasures derived from the Study of Marine Zoology.
'Woe to the man--
Who studies nature with a wanton eye,
Admires the work, but slips the lesson by.'
I.
As every fresh branch of investigation in natural history has a
tendency to gather around it a rapidly accumulating literature, some
explanation may probably be looked for from an author who offers a new
contribution to the public. And when, as in the present instance, the
writer's intentions are of an humble kind, it is the more desirable
that he should state his views at the outset. Nor can the force of this
claim be supposed to be lessened, from the gratifying fact, that the
present writer has already received a warm welcome from the public.
But, before entering upon any personal explanations, it may not be out
of place, in an introductory chapter such as the present, to bring
under review some of the objections which have been, and still continue
to be urged against this, in common with other departments of study,
which are attempted to be made popular. No branch of natural history
has been subjected to more disparaging opposition, partly, it must be
owned, from the misplaced enthusiasm of over zealous students, than
that of marine zoology.
There are two classes of readers, different in almost all other
respects, whose sympathies are united in dislike of such works as this.
The one, represented by men distinguished for their powers of original
research, are apt to undervalue the labours of such as are not,
strictly speaking, scientific writers. There is another class who, from
the prejudice of ignorance, look upon marine zoology as too trivial,
from the homeliness and minuteness of its details. The wonders of
astronomy, and the speculations suggested by geological studies, nay,
the laws of organization as exhibited in the higher forms of animal
life, are clear enough to this class of readers; but it is not easy to
convince them that design can be extracted from a mussel, or that a
jelly-fish exhibits a marvellous power of construction.
Now, in my belief, the opposition of the better educated of these two
classes of readers is the more dangerous, as it is unquestionably the
more ungenerous. If Professor Ansted, when treating of the surprising
neglect of geology, could thus express himself--'How many people do
we meet, otherwise well educated, who look with indifference, or even
contempt on this branch of knowledge,'--how much oftener may the
student of the humble theme of marine zoology bewail the systematic
depreciation of persons even laying claim to general scientific
acquirements. This may be illustrated by an observation, made in a
northern university, by a celebrated professor of Greek to a no less
celebrated professor of natural history. The latter, intently pursuing
his researches into the anatomy of a Nudibranche lying before him,
was startled by the sudden entrance of his brother professor, who
contemptuously advised him to give up skinning slugs, and take to more
manly pursuits.
There is one light in which the study of marine zoology may be
regarded, without necessarily offending the susceptibilities of the
learned, or exciting the sneers of the ignorant. The subject may be
pursued as an amusement--a pastime, if you will; and it is in no
higher character than that of a holiday caterer, that the author asks
the reader's company to the sea-side. No lessons but the simplest are
attempted to be conveyed in this little volume, and these in as quiet
and homely a style as possible.
Even in the light of an amusement, the author has something to say in
behalf of his favourite study. He believes it to be as interesting,
and fully as instructive as many infinitely more popular. For example:
The sportsman may love to hear the whirr of the startled pheasant, as
it springs from the meadow, and seeks safety in an adjoining thicket.
I am as much pleased with the rustling of a simple crab, that runs for
shelter, at my approach, into a rocky crevice, or beneath a boulder,
shaggy with corallines and sea-weed. He, too, while walking down some
rural lane, may love to see a blackbird hastily woo the privacy of a
hawthorn bush, or a frightened hare limp across his path, and strive to
hide among the poppies in the corn-field; I am equally gratified with
the sight of a simple razor-fish sinking into the sand, or with the
flash of a silver-bodied fish darting across a rock-pool.
Nay, even the trembling lark that mounts upwards as my shadow falls
upon its nest among the clover, is not a more pleasant object to my
eye, than the crustaceous hermit, who rushes within his borrowed
dwelling at the sound of footsteps. In fact, the latter considerably
more excites my kindly sympathies, from its mysterious curse of
helplessness. It cannot run from danger, but can only hide itself
within its shelly burden, and trust to chance for protection.
Neither the botanist nor the florist do I envy. The latter may love to
gather the 'early flowrets of the year,' or pluck an opening rose-bud,
but, although very beautiful, his treasures are ephemeral compared with
mine.
'Lilies that fester, smell far worse than weeds.'
But I can gather many simple ocean flowers, or weeds that--
'Look like flowers beneath the flattering brine,'
whose prettily tinted fronds will 'grow, bloom, and luxuriate' for
months upon my table. They do not want careful planting, or close
attention, or even--
'Like their earthly sisters, pine for drought,'
but are strong and hardy, like the pretty wild flowers that adorn our
fields and hedge-rows. In the pages of an album, I can, if so disposed,
feast my eyes for years upon their graceful forms, whilst their colours
will remain as bright as when first transplanted from their native
haunts by the sea-shore.
The entomologist delights to stroll in the forest and the field, to
hear the pleasant chirp of the cricket in the bladed grass, to watch
the honey people bustling down in the blue bells, or even to net the
butterfly as it settles on the sweet pea-blossom, while I am content to
ramble along the beach, and watch the ebb and flow of the restless sea--
'So fearful in its spleeny humours bent,
So lovely in repose--'
or search for nature's treasures among the weed-clad rocks left bare by
the receding tide.
A disciple of the above mentioned branch of natural history will
dilate with rapture upon the wondrous transformations which many of
his favourite insects undergo. But none that he can show surpasses in
grandeur and beauty the changes which are witnessed in many members of
the marine animal kingdom. He points to the leaf, to the bloom upon
the peach, brings his microscope and bids me peer in, and behold
the mysteries of creation which his instrument unfolds. 'Look,' he
says, pointing to the verdant leaf, 'at the myriads of beings that
inhabit this simple object. Every atom,' he exultingly exclaims, 'is
a standing miracle, and adorned with such qualities, as could not be
impressed upon it by a power less than infinite!' Agreed. But has not
the zoologist equal reason to be proud of his science and its hidden
marvels? Can he not exhibit equal miracles of divine power?
Take, as an example, one of the monsters of the deep, the whale; and
we shall find, according to several learned writers, that this animal
carries on its back and in its tissues a mass of creatures so minute,
that their number equals that of the entire population of the globe. A
single frond of marine algæ, in size
'No bigger than an agate stone
On the forefinger of an alderman,'
may contain a combination of living zoophytic beings so infinitely
small, that in comparison the 'fairies' midwife' and her 'team of
little atomies' appear monsters as gigantic, even as the whale or
behemoth, opposed to the gnat that flutters in the brightest sunbeam.
Again: in a simple drop of sea-water, no larger than the head of a pin,
the microscope will discover a million of animals. Nay, more; there are
some delicate sea-shells(_foraminifera_) so minute that the point of a
fine needle at one touch crushes hundreds of them.
'Full nature swarms with life; one wondrous mass
Of animals, or atoms organized,
Waiting the vital breath when Parent Heaven
Shall bid his spirit flow.'
Lastly, How fondly some writers dwell upon the many touching instances
of affection apparent in the feathered tribe, and narrate how carefully
and how skilfully the little wren, for example, builds its nest, and
tenderly rears its young. I have often watched the common fowl, and
admired her maternal anxiety to make her outspread wings embrace
the whole of her unfledged brood, and keep them warm. The cat, too,
exhibits this characteristic love of offspring in a marked degree. She
will run after a rude hand that grasps one of her blind kittens, and,
if possible, will lift the little creature, and run away home with it
in her mouth. Now, whether we look at the singular skill of the bird
building its nest, the hen sitting near and protecting its brood, or
the cat grasping her young in its jaws, and carrying them home in
safety, we shall find that all these charming traits are wonderfully
combined in one of the humblest members of the finny tribe, viz., the
common stickleback,--the little creature that boys catch by thousands
with a worm and a pin,--that lives equally content in the clear blue
sea or the muddy fresh water pool.
The author now finds that he has been much too prolix in these
preliminary observations to leave himself space for a lengthened
explanation of his reasons for again intruding upon the public. These
are neither original nor profound. But he cannot help expressing an
earnest hope that he may get credit from old friends, and perhaps from
some new, for wishing to show that the book of nature is as open as it
is varied and inexhaustible; and that, however jealously guarded are
many of the great secrets of organization, a knowledge of some of the
most familiar objects tends to inspire us alike with wonder and with
awe.
CHAPTER II.
A Glance at the Invisible World.
'There is a great deal of pleasure in prying into this world of
wonders, which Nature has laid out of sight, and seems industrious to
conceal from us.... It seems almost impossible to talk of things so
remote from common life and the ordinary notions which mankind receive
from the blunt and gross organs of sense, without appearing extravagant
and ridiculous.'--ADDISON.
II.
It is hardly possible to write upon marine zoology without either
more or less alluding to those many objects, invisible to the naked
eye, which call for the use of the microscope; and it seems equally
difficult for any one who has been accustomed to this instrument
to speak in sober terms of its wonderful revelations. The lines of
Cowper, as the youngest student in microscopic anatomy will readily
acknowledge, present no exaggerated picture of ecstasy:--
'I have seen a man, a worthy man,
In happy mood conversing with a fly;
And as he through his glass, made by himself,
Beheld its wondrous eye and plumage fine,
From leaping scarce he kept for perfect joy.'
It is proper, however, to notice that a serious objection has been
urged against the use of the microscope by young persons, namely, the
injurious effects of its habitual use upon the eyesight.
So far as my experience goes, I cannot deny that this objection is
well founded. Since I have begun to use the instrument, I am obliged,
if I wish to view distinctly any distant object, to distort my eyes
somewhat to the shape of ill-formed button-holes puckered in the
sewing. Some individuals, I am aware, foolishly affect this appearance,
from the notion that it exhibits an outward and visible sign of their
inward profundity of character. In my own case this result may have
arisen from my having worked principally at night or in the dusk.
'As to the sight being injured by a continuous examination of minute
objects,' writes Mr. Clark, a most scientific naturalist, 'I can truly
say this idea is wholly without foundation, if the pursuit is properly
conducted; and that, on the contrary, it is materially strengthened by
the use of properly adapted glasses, even of high powers; and in proof
I state, that twenty years ago I used spectacles, but the continued
and daily examination of these minutiæ (_foraminifera_) has so greatly
increased the power of vision, that I now read the smallest type
without difficulty and without aid. The great point to be attended to
is not to use a power that in the least exceeds the necessity; not
to continue the exercise of vision too long, and never by artificial
light; and to reserve the high powers of certain lenses and the
microscope for important investigations of very moderate continuance.
The observant eye seizes at a glance the intelligence required;
whilst strained poring and long optical exertions are delusive and
unsatisfactory, and produce those fanciful imaginations of objects
which have really no existence. The proper time for research after
microscopic objects is for _one_ hour after breakfast, when we are in
the fittest state for exertion.'
Mr. Lewes, again, speaking to the same point, viz., the eyes being
injured by microscopic studies, says:--'On evidence the most conclusive
I deny the accusation. My own eyes, unhappily made delicate by
over-study in imprudent youth, have been employed for hours daily
over the microscope without injury or fatigue. By artificial light,
indeed, I find it very trying; but by daylight, which on all accounts
is the best light for the work, it does not produce more fatigue than
any other steadfast employment of the eye. Compared with looking at
pictures, for instance, the fatigue is as nothing.'
In spite of the foregoing assertions, I feel it my duty to caution the
student against excess of labour. Let him ride his hobby cautiously,
instead of seeking to enrol his name among the martyrs of science,
of whom the noble Geoffry St. Hilaire, M. Sauvigny, and M. Strauss
Dürckheim, are noted modern examples. Each member of this celebrated
trio spent the latter part of his existence in physical repose, having
become totally blind from intense study over the microscope. But
setting aside the evils of excess, we must bear witness to the intense
delight which this pursuit affords when followed with moderation.
"'Tis sweet to muse upon the skill displayed
(Infinite skill!) in all that _He_ has made:
To trace in Nature's most minute design
The signature and stamp of power divine.
Contrivance intricate, expressed with ease,
_Where unassisted sight no beauty sees_."
As my aim is merely to give the reader a taste of the subject, and
whet his appetite for its more extensive pursuit at other sources, I
shall confine my remarks to a few of those creatures which are readily
to be found in any well-stocked aquarium. The number of animalculæ
and microscopic zoospores of plants, invisible to the naked eye,
with which such a receptacle is filled, even when the water is clear
as crystal, is truly marvellous. These animals mostly belong to the
class _Infusoria_, so called from their being found to be invariably
generated in any _infusion_, or solution of vegetable or animal matter,
which has begun to decay. Now, the water in an aquarium which has
been kept for any length of time necessarily becomes more or less
charged with the effete matter of its inhabitants, which, if allowed to
accumulate, would soon render the fluid poisonous to every living thing
within it. This result is happily averted by the Infusoria, which feed
upon the decaying substances in solution, while they themselves become
in their turn the food of the larger animals. Indeed, they constitute
almost the sole nutriment of many strong, muscular shell-fish, as
pholas, mussel, cockle, &c.; and doubtless help to maintain the life
of others, such as actiniæ, and even crabs, which, as is well known,
live and grow without any other apparent means of sustenance. Thus
the presence of Infusoria in the tank may be considered a sign of its
healthy condition, although their increase to such an extent as to give
a milky appearance to the water, is apt to endanger the well-being
of the larger, though delicate creatures. The peculiar phenomenon
alluded to arises from decaying matter, such as a dead worm or limpet,
which should be sought after and removed with all possible speed. The
whereabouts of such objectionable remains will be generally indicated
by a dense cloud of Infusoria hovering over the spot. The milkiness,
however, although it may look for the time unsightly, is ofttimes
the saving of the aquarium 'stock.' When these tiny but industrious
scavengers have completed their task of purification, they will cease
to multiply, and mostly disappear, leaving the water clear as crystal.
I believe it is the absence or deficient supply of Infusoria that
sometimes so tantalizingly defeats the attempts of many persons to
establish an aquarium. Pure deep-sea water, although never without
them, often contains but very few, hence great caution is necessary not
to overstock the tank filled with it, otherwise the animals will die
rapidly, although the water itself appears beautifully transparent.
Of Infusoria there are many species. They are nearly all, at one stage
or other of their existence, extremely vivacious in their movements;
so much so, indeed, that it becomes a matter of difficulty to observe
them closely. Some have the power of darting about with astonishing
velocity, others unceasingly gyrate, or waltz around with the grace of
a Cellarius; while not a few content themselves by, slug-like, dragging
their slow length along. The last are frequently startled from their
propriety and aplomb by the rapid evolutions of their terpshicorean
neighbours. Some, again, grasping hold of an object by one of their
long filaments, revolve rapidly round it, whilst others spring, leap,
and perform sundry feats of acrobatism that are unmatched in dexterity
by any of the larger animals.
I may here observe that the motions and general structure of many of
the microscopic forms of vegetation, so much resemble those of some
of the infusoria, that it has long puzzled naturalists to distinguish
between them with any degree of certainty. The chief distinction
appears to lie in the nature of their food. Those forms which are truly
vegetable can live upon purely inorganic matter, while the animals
require that which is organized. The plants also live entirely by the
absorption of fluid through the exterior, while the animalculæ are
capable of taking in solid particles into the interior of the body.
Their mode of multiplication, and the metamorphoses they undergo, are
much alike in both classes, being, during one stage of their existence,
still and sometimes immovably fixed to stones, sea-weed, &c., and at
another freely swimming about. Notwithstanding the similarities here
stated, the appearance of certain of the species is as various as it
is curious. One of the commonest species of the Infusoria (_Paramecium
caudatum_) is shaped somewhat like a grain of rice, with a piece
chipped out on one side, near the extremity of its body. It swims about
with its unchipped extremity foremost, rotating as it goes. During the
milky condition of the water (before alluded to), these creatures swarm
to such a degree, that a single drop of the fluid, when placed under
the microscope, appears filled with a dense cloud of dancing midges.
Another (_Kerona silurus_) may be said to resemble a coffee-bean, with
a host of _cilia_, or short bristles, on the flat side. These are used
when swimming or running. But perhaps the most singular and beautiful
of all the infusorial animalcules are the _Vorticellæ_, which resemble
minute cups or flower-bells, mounted upon slender retractile threadlike
stalks, by which they are moored to the surface of the weeds and
stones. They are called Vorticellæ on account of the little vortices
or whirlpools which they continually create in the water, by means of
a fringe of very minute cilia placed round the brim of their cups.
These cilia are so minute as to require a very high microscopic power
to make them visible, and even then they are not easily detected, on
account of their extremely rapid vibration, which never relaxes while
the animal is in full vigour. On the other hand, when near death,
their velocity diminishes, and ample opportunity is afforded for
observing that the movements consist of a rapid bending inwards and
outwards, over the edge of the cup. This is best seen in a side view.
The action is repeated by each cilium in succession, with such rapidity
and regularity that, when viewed from above, the fringe looks like the
rim of a wheel in rapid revolution. A similar appearance, produced
by the same cause, in another class of animalcula, of much more
complex structure than the Vorticellæ, has procured for it the name of
_Rotifera_, or wheel-bearers. The result of this combined movement of
the cilia is, that a constant stream of water is drawn in towards the
centre of the cup, and thrown off over the sides, when, having reached
a short distance beyond the edge, it circles rapidly in a small vortex,
curling downwards over the lips. These currents are rendered evident
by floating particles in the water. The possession of these vibratile
cilia is not peculiar to this class of animals; indeed, there is good
reason to believe that there is scarcely a living creature, from the
lowest animalcule, or plant germ, up to man himself, that is not
provided with them in some part or other. In many of these Infusoria
the cilia constitute the organs of locomotion; while in the higher
forms they serve various other purposes, but chiefly that of directing
the flow of the various internal fluids through their proper channels.
But the peculiar and perhaps most wonderful organ of the Vorticella,
is its stalk or mooring thread. This though generally of such extreme
tenuity as to be almost invisible with ordinary microscopes, yet
exhibits a remarkable degree of strength and muscular activity in
its movements, which apparently are more voluntary than those of the
cilia. Its action consists of a sudden contraction from a straight to
a spiral form with the coils closely packed together, by which the
head or bell is jerked down almost into contact with the foot of the
stalk; after a few seconds the tension seems gradually relaxed, the
coils are slowly unwound, and the stalk straightens itself out. This
action takes place at irregular intervals, but it is seldom that more
than a minute elapses between each contraction. It (the contraction)
invariably happens when the animal is touched or alarmed, and is,
consequently, very frequent when the water swarms with many other
swimming animalcula. When it takes place the flower-bell generally
closes up into a little round ball, which opens out again only when
the stalk becomes fully extended. From this we might almost infer that
some animalcule, or other morsel of food, had been seized and retained
within the cup; moreover, that the contraction of the stalk assisted in
securing or disposing of the prey. This, however, is uncertain.
The motions of the Vorticella do not seem much affected by the stalk
losing hold of its attachment; but the result of such an accident
taking place is that the cilia cause the animal to swim through the
water, trailing its thread behind it, and the contraction of the latter
merely causes it to be drawn up to the head.
There are various species of Vorticellæ. That just described is the
simplest, consisting merely of a hemispherical ciliated cup, attached
to a single thread. It is barely visible to the naked eye. But there
is a compound species which I have this year found to be extremely
abundant in my aquarium,--whose occupants, both large and small, it
excels in singularity and beauty. In structure it is to the simple
Vorticella what a many-branched zoophyte is to an _Actinia_. My
attention was first drawn to the presence of this creature by observing
some pebbles and fronds of green ulva thickly coated with a fine
flocculent down. On closer inspection this growth appeared to consist
of a multitude of feathery plumes, about one-sixteenth of an inch in
height, and individually of so fine and transparent a texture as to be
scarcely discernible to the unassisted sight. On touching one with the
point of a fine needle it would instantly shrink up into a small but
dense mass, like a ball of white cotton--scarcely so large as a fine
grain of sand. In a few seconds it would again unfold and spread itself
out to its original size. By carefully detaching a specimen with the
point of a needle or pen-knife, and transferring it, along with a drop
of water upon a slip of glass, to the stage of the microscope, a sight
was presented of great wonder and loveliness:--
'The more I fixed mine eye,
Mine eye the more new wonders did espye!'
Let the reader imagine a tree with slender, gracefully curved, and
tapering branches thickly studded over with delicate flower-bells
in place of leaves. Let him suppose the bells to be shaped somewhat
between those of the fox-glove and convolvolus, and the stem, branches,
bells, and all, made of the purest crystal. Let him further conceive
every component part of this singular structure to be tremulous with
life-like motion, and he will have as correct an idea as words can give
of the complex form of this minute inhabitant of the deep. Moreover,
while gazing at it through the microscope, the observer is startled
by the sudden collapse of the entire structure. The lovely tree has
shrunk together into a dense ball, in which the branching stem lies
completely hidden among the flower-bells--themselves closed up into
little spherules, so closely packed together that the entire mass
resembles a piece of herring-roe. This contraction is so instantaneous
that the mode in which it is accomplished cannot be observed until the
tree is again extended. As the re-extension takes place very slowly, we
are enabled to observe that each branchlet has been coiled in a spiral
form, like the thread of the simple Vorticella previously described;
and also that the main stem, above the lowest branch, was coiled up in
the same way, but not so closely, and that the part below the lowest
branch had, curiously enough, remained straight. Sometimes, in large
and numerously branched specimens, one or two of the lowest members
do not contract at the same time with the rest, but do so immediately
afterwards, as if they had been startled by the shrinking movements of
their neighbours. Sometimes these lowest branches will contract alone,
while all the others remain fully extended,--a fact that would almost
seem to indicate that they possessed an independent life of their own.
In the accompanying engraving I have attempted faithfully to portray
one of these wonderful creatures. Fig. 1 represents it fully extended,
while Fig. 2 indicates its collapsed form. There is another curious
circumstance which I have fortunately observed in connection with this
Vorticella, a description of which will perhaps be interesting to the
reader. I allude to the casting off of what may be called the fruit
of the tree. When this event takes place, the buds (or fruit) dart
about with such rapidity, that it is almost impossible to keep them
in the field of view for the briefest space of time. A represents the
enchanted fruit hanging on the tree; B shows it as it swims about.
[Illustration: Fig. 1. and Fig. 2.]
Although not exactly fruit, it is, no doubt, the means by which
the Vorticellæ are propagated, for it is known that many fixed
zoophytes, and even some plants, produce free swimming germs or spores,
which afterwards become fixed, and grow up into forms like those
which produced them. In some of the branching zoophytes (_Coryne_,
_Sertularia_, &c.), the germs are exactly like little medusae, being
small, gelatinous cups fringed with tentacula, by means of which they
twitch themselves along with surprising agility. In this Vorticella,
however, it is more like one of the ciliated Infusoria. The first one
that I saw attached I conceived to be a remarkably large bell, with
its mouth directed towards me, but the cilia with which it appeared
to be fringed were unusually large and distinct. The movements of
these appendages being comparatively slow, it was most interesting
to watch them as they successively bent inwards and rose again, like
the steady swell of a tidal wave, or an eccentric movement in some
piece of machinery, making a revolution about twice in a second, and
in the opposite direction to the hands of a clock. Suddenly the tree
contracted, when, to my surprise, I observed the bell, which not an
instant before appeared attached, now floating freely in the water,
its ciliary movements not being in the least interrupted. Presently,
however, they became brisker, the bell turned over on its side, and,
ere the tree had again expanded, darted out of view, not, however,
before I had remarked that it was not a bell, but a sphere flattened
on one side, and having its circular ring of cilia on the flat side,
with only a slight depression in the middle of it. There also appeared
to be a small granular nucleus immediately above this depression, the
rest of the body being perfectly transparent. I afterwards saw several
others attached to the tree, each seated about the centre of a branch;
but none of these were so fully developed. They were like little
transparent button mushrooms, and had all more or less of a nucleus
on the side by which they were attached. On only one of these did I
detect any cilia.
Mr. Gosse, in his 'Tenby,' gives a picture of an animal exceedingly
like what I have described; but from his account of it, there seems to
be some doubt of their identity. He calls it '_Zoothamnium spirale_,'
because the insertions of the branches were placed spirally around the
main stem, like those of a fir-tree. In my specimens the branches were
set alternately on opposite sides of the main trunk, and the whole was
curved like a drooping fern leaf or an ostrich feather, the bells being
mostly set on the convex side.
In conclusion, let me mention that it is an error to suppose, as many
persons do, that putrid water alone contains life. Infusoria occur,
as before hinted, in the clear waters of the ocean, in the water that
we drink daily, and also in the limpid burn that flows through our
valleys, or trickles like a silver thread down the mountain side.[1]
[1] Ehrenberg states that Infusoria are in a higher state of
organization when taken from pure streams than from putrid waters.
'Where the pool
Stands mantled o'er with green, invisible,
Amid the floating verdure millions stray.
Each liquid too, whether it pierces, soothes,
Inflames, refreshes, or exalts the taste,
With various forms abounds. Nor is the stream
Of purest crystal, nor the lucid air,
Though one transparent vacancy it seems,
Void of their unseen people. These, concealed
By the kind art of forming Heaven, escape
The grosser eye of man.'
Let it be remembered, too, that Infusoria, when found in either do not
themselves constitute the impurity of fresh or salt water; they merely
act as 'nature's invisible scavengers,' whose duty it is to remove
all nuisances that may spring up; and most unceasingly do these tiny
creatures labour in the performance of their all-important mission of
usefulness.
CHAPTER III.
Sea Anemones.
'The living flower that, rooted to the rock,
Late from the thinner element,
Shrunk down within its purple stem to sleep,
Now feels the water, and again
Awakening, blossoms out
All its green anther-necks.'
[Illustration:
1 Sir J. G. Dalyell's celebrated ACTINIA (Drawn from Nature Jan. 1860.)
2 A. CRASSICORNIS
3 CAVE DWELLER (_A. troglodytes_)]
III.
No marine objects have become more universally popular of late years
than Sea Anemones. Certainly none better deserve the attention which
has been, and is daily bestowed upon them by thousands of amateur
naturalists, who cannot but be delighted with the wondrous variety of
form, and the beauteous colouring which these zoophytes possess.
A stranger could scarcely believe, on looking into an aquarium, that
the lovely object before him, seated motionless at the base of the
vessel, with tentacula expanded in all directions, was not a simple
daisy newly plucked from the mountain side, or it may be a blooming
marigold or _Anemone_ from some rich parterre--instead of being, in
reality, a living, moving, animal-flower.
One great advantage which the _Actiniæ_ possess over certain other
inhabitants of the sea-shore, at least to the eye of the naturalist, is
the facility with which specimens may be procured for observation and
study. Scarcely any rock-pool near low water mark but will be found to
encompass a certain number of these curious creatures, while some rocky
excavations of moderate size will at times contain as many as fifty.
Should the tide be far advanced, the young zoologist need not despair
of success, for, by carefully examining the under part of the boulders
totally uncovered by the sea, he will frequently find specimens of the
smooth anemone, contracted and hanging listlessly from the surface of
the stone, like masses of green, marone, or crimson jelly.
The Actiniæ, and especially examples of the above mentioned species,
are extremely hardy and tenacious of life, as the following interesting
narrative will prove.
The late Sir John Dalyell writing in 1851, says, 'I took a specimen
of _A. mesembryanthemum_ (smooth anemone) in August 1828, at North
Berwick, where the species is very abundant among the crevices of the
rocks, and in the pools remaining still replenished after the recess of
the tide. It was originally very fine, though not of the largest size,
and I computed from comparison with those bred in my possession, that
it must have been then at least seven years old.'
Through the kindness of Dr. M'Bain, R.N., the writer has been permitted
to enjoy the extreme pleasure of inspecting the venerable zoophyte
above alluded to, which cannot now be much under thirty-eight years of
age!
In the studio of the above accomplished naturalist, 'Granny' (as she
has been amusingly christened) still dwells, her wants being attended
to with all that tenderness and care which her great age demands.
Sir J. Dalyell informs us that during a period of twenty years this
creature produced no less than 344 young ones. But, strange to say,
nearly the fortieth part of this large progeny consisted of monstrous
animals, the monstrosity being rather by redundance than defect. One,
for instance, was distinguished by two mouths of unequal dimensions
in the same disc, environed by a profusion of tentacula. Each mouth
fed independently of its fellow, and the whole system seemed to derive
benefit from the repast of either. In three years this monster became
a fine specimen, its numerous tentacula were disposed in four rows,
whereas only three characterize the species, and the tubercles of vivid
purple, regular and prominent, at that time amounted to twenty-eight.
From the foregoing statement we learn that this extraordinary animal
produced about 300 young during a period of twenty years, but, 'wonder
of wonders!' I have now to publish the still more surprising fact,
that in the spring of the year 1857, after being unproductive for many
years, it unexpectedly gave birth, during a single night, to no less
than 240 living models of its illustrious self!
This circumstance excited the greatest surprise and pleasure in the
mind of the late Professor Fleming, in whose possession this famous
Actinia then was.
Up to this date (January 1860) there has been no fresh instance of
fertility on the part of Granny, whose health, notwithstanding her
great reproductive labours and advanced age, appears to be all that
her warmest friends and admirers could desire. Nor does her digestive
powers exhibit any signs of weakness or decay; on the contrary, that
her appetite is still exquisitely keen, I had ample opportunity of
judging. The half of a newly opened mussel being laid gently upon the
outer row of tentacula, these organs were rapidly set in motion, and
the devoted mollusc engulphed in the course of a few seconds.
The colour of this interesting pet is pale brown. Its size, when fully
expanded, no larger than a half-crown piece. It is not allowed to
suffer any annoyance by being placed in companionship with the usual
occupants of an aquarium, but dwells alone in a small tank, the water
of which is changed regularly once a week. This being the plan adopted
by the original owner of Granny, is the one still followed by Dr.
M'Bain, whose anxiety is too great to allow him to pursue any other
course, for fear of accident thereby occurring to his protegée.
A portrait of Granny, drawn from nature, will be found on Plate 2.
_A. troglodytes_[2] (cave-dweller) is a very common, but interesting
object. The members of this species are especial favourites with the
writer, from their great suitableness for the aquarium. They vary
considerably in their appearance from each other. Some are red, violet,
purple, or fawn colour; others exhibit a mixture of these tints, while
not a few are almost entirely white. There are certain specimens which
disclose tentacula, that in colour and character look, at a little
distance, like a mass of eider-down spread out in a circular form. A
better comparison, perhaps, presents itself in the smallest plumage of
a bird beautifully stippled, and radiating from a centre. The centre
is the mouth of the zoophyte, and is generally a light buff or yellow
colour. From each corner, in certain specimens, there branches out
a white horn that tapers to a very delicate point, and is oft times
gracefully curled like an Ionic volute, or rather like the tendril of a
vine.
[2] The above mentioned Actinia is extremely abundant on the shores
of the Frith of Forth. Sir J. Dalyell terms it _A. explorator_.
Local amateur naturalists frequently reject the specific name
of 'Troglodytes,' and adopt the more musical appellation of
'Daisy-Anemone.' Such error seems very pardonable, when we remember the
close resemblance which the creature when expanded bears to the daisy
of the field. In no single instance have I met with specimens of the
true _A. bellis_ at the above named locality, nor do I think any have
ever been found by previous naturalists.
In addition to the pair of horns alluded to, may sometimes be seen a
series of light-coloured rays, occurring at regular intervals around
the circumference of the deep tinted tentacula, and thereby producing
to the eye of the beholder a most pleasing effect.
As a general rule, never attempt to capture an anemone unless it be
fully expanded, before commencing operations. By this means you will be
able to form a pretty accurate estimate of its appearance in the tanks.
This condition of being seen necessitates, of course, its being covered
with water, and, consequently, increases the difficulty of capturing
your prize, especially when the creature happens to have taken up a
position upon a combination of stone and solid rock, or in a crevice,
or in a muddy pool, which when disturbed seems as if it would never
come clear again.
It is, in consequence, advisable to search for those situated in
shallow water, the bottom of which is covered with clean sand. When
such a favourable spot is found, take hammer and chisel and commence
operations. Several strokes may be given before any alarm is caused to
the anemone, provided it be not actually touched. No sooner, however,
does the creature feel a palpable vibration, and suspect the object of
such disturbance, than, spurting up a stream of water, it infolds its
blossom, and shrinks to its smallest possible compass. At same time
apparently tightens its hold of the rock, and is, indeed, often enabled
successfully to defy the utmost efforts to dislodge it.
After a little experience, the zoologist will be able to guess whether
he is likely to succeed in getting his prize perfect and entire; if
not, let me beg of him not to persevere, but immediately try some other
place, and hope for better fortune.
Although apparently sedentary creatures, the Actiniæ often prove
themselves to be capable of moving about at will over any portion of
their subaqueous domain. Having selected a particular spot, they will
ofttimes remain stationary there many consecutive months. A smooth
anemone that had been domesticated for a whole year in my aquarium
thought fit to change its station and adopt a roving life, but at last
'settled down,' much to my surprise, upon a large mussel suspended
from the surface of the glass. Across both valves of the mytilus the
'mess.' attached by its fleshy disc, remained seated for a considerable
length of time. It was my opinion that the mussel would eventually be
sacrificed. Such, however, was not the case, for on the zoophyte again
starting off on a new journey, the mollusc showed no palpable signs of
having suffered from the confinement to which it had so unceremoniously
been subjected.
The appearance of this anemone situated several inches from the base
of the vessel, branching out from such an unusual resting-place, and
being swayed to and fro, as it frequently was, by the contact of a
passing fish, afforded a most pleasing sight to my eye. Indeed, it was
considered for a while one of the 'lions' of the tank, and often became
an object of admiration not only to my juvenile visitors, but also to
many 'children of larger growth.'
There is a curious fact in connection with the Actiniæ which deserves
to be chronicled here. I allude to the apparent instinct which they
possess. This power I have seen exercised at various times. The
following is a somewhat remarkable instance of the peculiarity in
question.
In a small glass vase was deposited a choice _A. dianthus_, about an
inch in diameter. The water in the vessel was at least five inches
in depth. Having several specimens of the _Aplysiæ_, I placed one in
companionship with the anemone, and was often amused to observe the
former floating head downward upon the surface of the water. After a
while it took up a position at the base of the vase, and remained there
for nearly a week. Knowing the natural sluggishness of the animal,
its passiveness did not cause me any anxiety. I was rather annoyed,
however, at observing that the fluid was becoming somewhat opaque,
and that the Dianthus remained entirely closed, and intended to find
out the cause of the phenomena, but from some reason or other failed
to carry out this laudable purpose at the time. After the lapse of a
few days, on looking into the tank, I was delighted to perceive the
lace-like tentacula of the actinia spread out on the surface of the
water, which had become more muddy-looking than before.
I soon discovered that the impurity in question arose from the Aplysia
(whose presence in the tank I had forgotten) having died, and its body
being allowed to remain in the vessel in a decaying state. The deceased
animal on being removed emitted an effluvium so intolerably bad that
it seemed like the concentrated essence of vile odours. The water, of
course, must have been of the most deadly character, yet had this most
delicate of sea-anemones existed in it for several consecutive days.
In order further to test how long my little captive would remain alive
in its uncongenial habitation, I cruelly refused to grant any succour,
but must own to having felt extremely gratified at perceiving, in the
course of a few days, that instead of remaining with its body elongated
to such an unusual extent, the Dianthus gradually advanced along the
base, then up the side of the vessel, and finally located itself in
a certain spot, from which it could gain easy access to the outer
atmosphere.
After this second instance of intelligence (?) I speedily transferred
my pet to a more healthy situation.
Having procured a small colony of Actiniæ, you need be under no anxiety
about their diet, for they will exist for years without any further
subsistence than is derived from the fluid in which they live. Yet
strange as the statement will appear to many persons, the Actiniæ
are generally branded with the character of being extremely greedy
and voracious. 'Nothing,' says Professor Jones, 'can escape their
deadly touch. Every animated thing that comes in contact with them is
instantly caught, retained, and mercilessly devoured. Neither strength
nor size, nor the resistance of the victim, can daunt the ravenous
captor. It will readily grasp an animal, which, if endowed with similar
strength, advantage, and resolution, could certainly rend its body
asunder. It will endeavour to gorge itself with thrice the quantity of
food that its most capacious stomach is capable of receiving. Nothing
is refused, provided it be of animal substance. All the varieties of
the smaller fishes, the fiercest of the crustacea, the most active of
the annelidans, and the soft tenants of shells among the mollusca, all
fall a prey to the Actiniæ.'
This is a sweeping statement, and, although corroborated by Sir J.
Dalyell and others, is one that requires to be received with a certain
degree of caution. It most certainly does not apply to _A. bellis_,
_A. parisitica_, _A. dianthus_, _troglodytes_, or any other members of
this group; and to a very limited extent only is it applicable to _A.
coriacea_ or _A. mesembryanthemum_.
As may readily be conceived, the writer could not keep monster
specimens, such as are often found at the sea-shore; but surely if
the statement were correct that, _as a general rule_, the actiniæ
eat living crabs, the phenomenon would occasionally occur with
moderate-sized specimens, when kept in companionship with a mixed
assembly of crustaceans. Yet in no single instance have I witnessed a
small crab sacrificed to the gluttony of a small anemone.
With regard to _A. mesembryanthemum_, _A. bellis_, and _A. dianthus_,
they get so accustomed to the presence of their crusty neighbours,
as not to retract their expanded tentacula when a hermit crab, for
instance, drags his lumbering mansion across, or a fiddler crab steps
through the delicate rays, like a sky terrier prancing over a bed of
tulips.
Thus much I have felt myself called upon to say in defence of certain
species of Actiniæ; but with regard to _A. crassicornis_, I must
candidly own the creature is greedy and voracious to an extreme degree.
Like many other writers, I have seen scores of this species of Actiniæ
that contained the remains of crabs of large dimensions, but at one
time considered that the latter were dead specimens, which had been
drifted by the tide within reach of the Actiniæ, and afterwards
consumed. That such, indeed, was the correct explanation in many
instances I can scarcely doubt, from the disproportionate bigness of
the crabs as compared with the anemones, but feel quite confident, that
in other instances, the crustacea were alive when first caught by their
voracious companions.
To test the power of the 'crass.,' I have frequently chosen a specimen
well situated for observation, and dropped a crab upon its tentacula.
Instantly the intruding animal was grasped (perhaps merely by a claw),
but in spite of its struggles to escape, was slowly drawn into the
mouth of its captor, and eventually consumed. In one case, after the
crab had been lost to view for the space of three minutes only, I drew
it out of the Actinia, but although not quite dead, it evidently did
not seem likely to survive for any length of time.
In collecting Actiniæ great care should be taken in detaching them from
their position. If possible, it is far the better plan not to disturb
them, but to transport them to the aquarium on the piece of rock or
other substance to which they may happen to be affixed. This can in
general be done by a smart blow of the chisel and hammer.
Should the attempt fail, an endeavour should be made to insinuate the
finger nails under the base, and so detach each specimen uninjured.
This operation is a delicate one, requiring practice, much patience,
and no little skill. We are told by some authors that a slight rent
is of no consequence, since the anemone is represented as having the
power of darning it up. It may be so, but for my part I am inclined in
other instances to consider the statement more facetious than truthful.
In making this remark, I allude solely to the disc of the animal, an
injury to which I have never seen repaired. On the other hand, it is
well known that certain other parts may be destroyed with impunity. If
the tentacula, for instance, be cut away, so great are the reproductive
powers of the Actiniæ, that in a comparatively short space of time the
mutilated members will begin to bud anew.
'If cut transversely through the middle, the lower portion of the
body will after a time produce more tentacula, pretty near as they
were before the operation, while the upper portion swallows food as
if nothing had happened, permitting it indeed at first to come out at
the opposite end; just as if a man's head being cut off would let out
at the neck the bit taken in at the mouth, but which it soon learns to
retain and digest in a proper manner.'
The smooth anemone being viviparous, as already hinted, it is no
uncommon circumstance for the naturalist to find himself unexpectedly
in possession of a large brood of infant zoophytes, which have been
ejected from the mouth of the parent.
There is often an unpleasant-looking film surrounding the body of
the Actiniæ. This 'film' is the skin of the animal, and is cast off
very frequently. It should be brushed away by aid of a camel-hair
pencil. Should any rejected food be attached to the lips, it may be
removed by the same means. When in its native haunts this process is
performed daily and hourly by the action of the waves. Such attention
to the wants of his little captives should not be grudgingly, but
lovingly performed by the student. His labour frequently meets with
ample reward, in the improved appearance which his specimens exhibit.
Instead of looking sickly and weak, with mouth pouting, and tentacula
withdrawn, each little pet elevates its body and gracefully spreads
out its many rays, apparently for no other purpose than to please its
master's eye.
_A. mesembryanthemum_ (in colloquial parlance abbreviated to 'mess.'),
is very common at the sea-shore. It is easily recognised by the row of
blue torquoise-like beads, about the size of a large pin's head, that
are situated around the base of the tentacula. This test is an unerring
one, and can easily be put in practice by the assistance of a small
piece of stick, with which to brush aside the overhanging rays.
_A. crassicornis_ grows to a very large size. Some specimens would,
when expanded, cover the crown of a man's hat, while others are no
larger than a 'bachelor's button.' Unless rarely marked, I do not now
introduce the 'crass.' into my tanks, from a dislike, which I cannot
conquer, to the strange peculiarity which members of this species
possess, of turning themselves inside out, and going through a long
series of inelegant contortions. Still, to the young zoologist, this
habit will doubtless be interesting to witness. One author has named
these large anemones 'quilled dahlias;' and the expression is so
felicitous, that if a stranger at the sea-side bear it in mind, he
could hardly fail to identify the 'crass.,' were he to meet with
a specimen in a rocky pool. Not the least remarkable feature in
connection with these animal-flowers, is the extraordinary variety of
colouring which various specimens display.
_A. troglodytes_, is seldom found larger than a florin. Its general
size is that of a shilling. From the description previously given, the
reader will be able to make the acquaintance of this anemone without
any trouble whatever.
_A. dianthus_ (Plumose anemone), is one of the most delicately
beautiful of all the Actiniæ; it can, moreover, be very readily
identified in its native haunts. Its colour is milky-white,--body,
base, and tentacula, all present the same chaste hue. Specimens,
however, are sometimes found lemon-coloured, and occasionally of a deep
orange tint. Various are the forms which this zoophyte assumes, yet
each one is graceful and elegant.
The most remarkable as well as the most common shape, according to
my experience, is that of a lady's corset, such as may often be seen
displayed in fashionable milliners' windows. Even to the slender waist,
the interior filled with a mass of lace-work, the rib-like streaks, and
the general contour, suggestive of the Hogarthian line of beauty, the
likeness is sustained.
When entirely closed, this anemone, unlike many others, is extremely
flat, being scarcely more than a quarter of an inch in thickness;
indeed, so extraordinary is the peculiarity to which I allude, that a
novice would have great difficulty in believing that the object before
him was possessed of expansive powers at all, whereas, in point of
fact, it is even more highly gifted in this respect than any other
species of Actiniæ.
CHAPTER IV.
Edible Crab, Shore-Crab, Spider-Crab, &c.
'With a smart rattle, something fell from the bed to the floor; and
disentangling itself from the death drapery, displayed a large pound
_Crab_.... Creel Katie made a dexterous snatch at a hind claw, and,
before the Crab was at all aware, deposited him in her patch-work
apron, with a "_Hech, sirs, what for are ye gaun to let gang siccan a
braw partane?_"'--T. HOOD
[Illustration:
1 EDIBLE CRAB
2 EDIBLE CRAB, casting its shell, from Nature
3 SPIDER CRAB
4 COMMON SHORE-CRAB
5 MINUTE PORCELAIN-CRAB]
IV.
The foregoing motto, extracted from a humorous tale by 'dear Tom Hood,'
which appeared in one of his comic annuals,--or volumes of 'Laughter
from _year_ to _year_,' as he delighted to call them,--may not inaptly
introduce the subject of this chapter.
The term _partane_ is generally applied in Scotland to all the true
crabs (_Brachyura_). An esteemed friend, however, informs me that in
some parts it is more particularly used to denote the Edible Crab
_(Cancer pagurus_), which is sold so extensively in the fishmongers'
shops. However that may be, there is no doubt it was a specimen of this
genus that Creel Katie so boldly captured.
Now this crab, to my mind, is one of the most interesting objects of
the marine animal kingdom, and I would strongly advise those of my
readers who may have opportunities of being at the sea-side to procure
a few youthful specimens. Its habits, according to my experience, are
quite different from those of its relative, the Common Shore-Crab
(_Carcinus_ _mænas_), or even the Velvet Swimming-Crab (_Portunus
puber_). Unlike these, it does not show any signs of a vicious temper
upon being handled, nor does it scamper away in hot haste at the
approach of a stranger. Its nature, strange as the statement may appear
to many persons, seems timid, gentle, and fawn-like.
On turning over a stone, you will perhaps perceive, as I have often
done, three or four specimens, and, unless previously aware of the
peculiarity of their disposition, you will be surprised to see each
little fellow immediately fall upon his back, turn up the whites of his
eyes, and bring his arms or claws together,--
'As if praying dumbly,
Over his breast:'
making just such a silent appeal for mercy as a pet spaniel does
when expecting from his master chastisement for some _faux pas_. One
of these crabs may be taken up and placed in the hand without the
slightest fear. It will not attempt to escape, but will passively
submit to be rolled about, and closely examined at pleasure. Even when
again placed in its native element, minutes will sometimes elapse
before the little creature can muster up courage to show his 'peepers,'
and gradually unroll its body and limbs from their painful contraction.
Most writers on natural history entertain an opinion totally at
variance with my own in regard to the poor _Cancer pagurus_, of whom
we are speaking. By some he is called a fierce, cannibalistic, and
remorseless villain, totally unfit to be received into respectable
marine society. Mr. Jones relates how he put half a dozen specimens
into a vase, and on the following day found that, with the exception
of two, all had been killed and devoured by their companions; and in a
trial of strength which speedily ensued between the pair of 'demons in
crustaceous guise,' one of these was eventually immolated and devoured
by his inveterate antagonist. Sir J. Dalyell mentions several similar
instances of rapacity among these animals. Now, these anecdotes I do
not doubt, but feel inclined, from the results of my own experience, to
consider them exceptional cases.
When studying the subject of exuviation, I was in the habit of
keeping half a dozen or more specimens of the Edible Crab together as
companions in the same vase; but except when a 'friend and brother'
slipped off his shelly coat, and thus offered a temptation too great
for crustaceous nature to withstand, I do not remember a single
instance of cannibalism. True, there certainly were occasionally
quarrelling and fighting, and serious nocturnal broils, whereby life
and limb were endangered; but then such mishaps will frequently occur,
even in the best regulated families of the higher animals, without
these being denounced as a parcel of savages.
Compared to _Cancer pagurus_, the Shore-Crab appears in a very
unamiable light. When the two are kept in the same vase, they exhibit
a true exemplification of the wolf and the lamb. This, much to my
chagrin, was frequently made evident to me, but more particularly so
on one occasion, when I was, from certain circumstances, compelled to
place a specimen of each in unhappy companionship. Here is a brief
account of how they behaved to each other: The poor little lamb (_C.
pagurus_) was kept in a constant state of alarm by the attacks of her
fellow-prisoner (_C. mænas_) from the first moment that I dropped her
in the tank. If I gave her any food, and did not watch hard by until it
was consumed, the whole meal would to a certainty be snatched away. Not
content with his booty, the crabbie rascal of the shore would inflict a
severe chastisement upon his rival in my favour, and not unfrequently
attempt to wrench off an arm or a leg out of sheer wantonness. To
end such a deplorable state of matters, I very unceremoniously took
up wolf, and lopped off one of his large claws, and also one of his
hind legs. By this means I stopped his rapid movements to and fro,
and, moreover, deprived him somewhat of his power to grasp an object
forcibly. In spite of his mutilations, he still exhibited the same
antipathy to his companion, and, as far as possible, made her feel the
weight of his jealous ire. Retributive justice, however, was hanging
over his crustaceous head. The period arrived when nature compelled
him to change his coat. In due time the mysterious operation was
performed, and he stood forth a new creature, larger in size, handsomer
in appearance, but for a few days weak, sickly, and defenceless. His
back, legs, and every part of his body were of the consistency of
bakers' dough. The lamb well knew her power, and though much smaller in
size than her old enemy, she plucked up spirit and attacked him; nor
did she desist until she had seemingly made him cry peccavi, and run
for his life beneath the shelter of some friendly rock. Without wishing
to pun, I may truly say the little partane came off with _eclat_,
having my warmest approbation for her conduct, and a _claw_ in her arms
as token of her prowess. I knew that when wolf was himself again there
would be a scene. Reprisals, of course, would follow. Therefore, rather
than permit a continuance of such encounters, I separated the crabs,
and introduced them to companions more suited to the nature of each.
The difference exhibited in the form and development of the tail in
the ten-footed Crustacea (_Decapoda_)--as for instance, the crab, the
lobster, and the hermit-crab--is so striking that naturalists have
very appropriately divided them into three sections, distinguished by
terms expressive of these peculiarities of structure: 1st, _Brachyura_,
or short-tailed decapods, as the Crabs; 2d, _Anomoura_, or irregular
tailed, as the Hermit-crabs; 3d, _Macroura_, or long-tailed, as
Lobster, Cray-fish, &c.
It is to a further consideration of a few familiar examples of the
first mentioned group that I propose to devote the remainder of this
chapter.
Few subjects of study are more difficult and obscure than such as
belong to the lower forms of the animal kingdom. However carefully
we may observe the habits of these animals, our conclusions are too
often apt to be unsound, from our proneness to judge of their actions
as we would of the actions of men. As a consequence, an animal may
be pronounced at one moment quiet and intelligent, and at another
obstinate and dull, while perhaps, if the truth were known, it deserves
neither verdict.
For my own part, the more I contemplate the habits of many members
of the marine animal kingdom, the more am I astounded at the seeming
intelligence and purpose manifested in many of their actions. Prior,
apparently, must have been impressed with the same idea, for he says,
speaking of animals,--
"Vainly the philosopher avers
That reason guides our deeds, and instinct _theirs_.
How can we justly different causes frame
_When the effects entirely are the same?_
Instinct and reason, how can we divide?
'Tis the fool's ignorance, and the pedant's pride!"
This train of thought has been suggested to my mind by viewing the
singular conduct of a Shore-Crab, whom I kept domesticated for many
consecutive months. Three times during his confinement he cast his
exuvium, and had become nearly double his original size. His increased
bulk made him rather unfit for my small ocean in miniature, and gave
him, as it were, a loblolliboy appearance. Besides, he was always
full of mischief, and exhibited such pawkiness, that I often wished
he were back again to his sea-side home. Whenever I dropped in a meal
for my Blennies, he would wait until I had retired, and then rush out,
disperse the fishes, and appropriate the booty to himself. If at all
possible, he would catch one of my finny pets in his arms, and speedily
devour it. Several times he succeeded in so doing; and fearing that
the whole pack would speedily disappear, unless stringent measures for
their preservation were adopted, I determined to eject the offender.
After considerable trouble, his crabship was captured, and transferred
to a capacious glass.
The new lodging, though not so large as the one to which for so long
a time he had been accustomed, was nevertheless clean, neat, and
well-aired. At its base stood a fine piece of polished granite, to
serve as a chair of state, beneath which was spread a carpet of rich
green ulva. The water was clear as crystal; in fact, the accommodation,
as a whole, was unexceptionable. The part of host I played myself,
permitting no one to usurp my prerogative. But in spite of this,
the crab from the first was extremely dissatisfied and unhappy with
the change, and for hours together, day after day, he would make
frantic and ineffectual attempts to climb up the smooth walls of
his dwelling-place. Twice a day, for a week, I dropped in his food,
consisting of half a mussel, and left it under his very eyes; nay, I
often lifted him up and placed him upon the shell which contained his
once-loved meal; still, although the latter presented a most inviting
come-and-eat kind of appearance, not one particle would he take, but
constantly preferred to raise himself as high as possible up the sides
of the vase, until losing his balance, he as constantly toppled over
and fell upon its base.
This behaviour not a little surprised me. Did it indicate sullenness?
or was it caused by disappointment? Was he aware that escape from
his prison without aid was impossible, and consequently exhibited
the pantomime, which I have described, to express his annoyance, and
longing for the home he had lately left?
Thinking that perhaps there was not sufficient sea-weed in the glass,
I added a small bunch of _I. edulis_. Having thus contributed, as I
believed, to the comfort of the unhappy crab, I silently bade him
_bon soir_. On my return home, I was astonished by the servant, who
responded to my summons at the door, blurting out in a nervous manner,
'O sir! the creature's run awa!' 'The creature--what creature?' I
inquired. 'Do ye no ken, sir?--the wee crabbie in the tumler!'
I could scarcely credit the evidence of my sight when I saw the
'tumler' minus its crustaceous occupant. The first thought that
occurred to me was as to where the crab could be found. Under chairs,
sofa, and fender, behind book-case, cabinet, and piano, in every
crevice, hole, and corner, for at least an hour did I hunt without
success. Eventually the hiding-place of the fugitive was discovered in
the following singular manner: As I sat at my desk, I was startled by
a mysterious noise which apparently proceeded from the interior of my
'Broadwood,' which, by-the-by, I verily believe knows something about
the early editions of 'The battle of Prague,' The strings of this
venerable instrument descend into ill-disguised cupboards, so that
at the lower part there are two doors, or, in scientific language,
'valves.' On opening one of these, what should I see but the poor
crab, who, at my approach, 'did' a kind of scamper polka over the
strings. This performance I took the liberty of cutting short with
all possible speed. On dragging away the performer, I found that his
appearance was by no means improved since I saw him last. Instead of
being ornamented with gracefully-bending polypes, he was coated, body
and legs, with dust and cobwebs. I determined to try the effect of a
bath, and presently had the satisfaction of seeing him regain his usual
comely appearance. The next step was to replace him in his old abode;
and having done so, I felt anxious to know how the creature had managed
to scale his prison walls. The _modus operandi_ was speedily made
apparent; yet I feel certain that, unless one had watched as I did, the
struggles of this little fellow, the determination and perseverance he
exhibited would be incredible.
After examining his movements for an hour, I found, by dint of standing
on the points of his toes, poised on a segment of weed, that he managed
to touch the brim of the glass. Having got thus far, he next gradually
drew himself up, and sat upon the edge of the vessel. In this position
he would rest as seemingly content as a bird on a bush, or a schoolboy
on a gate.
My curiosity satisfied, the _C. mænas_ was again placed in the vase,
and every means of escape removed.
Here let me mention that I still had a Fiddler-Crab in my large tank,
who had formerly lived in companionship with the shore-crab above
mentioned. With 'the fiddler' I had no fault to find; he was always
modest and gentle, and gave no offence whatever to my Blennies. He
never attempted to embrace them, nor to usurp their lawful place at the
table, nor even to appropriate their meals. On the contrary, he always
crept under a stone, and closely watched the process of eating until
the coast was clear, when he would scuttle out, and feed, Lazarus-like,
upon any crumbs that might be scattered around.
Although so modest and retiring, I soon discovered that this little
crab possessed an ambitious and roving disposition. This made him
wish to step into the world without, and proceed on a voyage of
discovery--to start, indeed, on his own account, and be independent of
my hospitality, or the dubious bounty of his finny companions. Taking
advantage on one occasion of a piece of sandstone that rested on the
side of the aquarium, he climbed up its slanting-side, from thence he
stepped on to the top of the vessel, and so dropped down outside upon
the room floor. For nearly two days I missed his familiar face, but had
no conception that he had escaped, or that he wished to escape from his
crystal abode. It was by mere accident that I discovered the fact.
Entering my study, after a walk on a wet day, umbrella in hand, I
thoughtlessly placed this useful article against a chair. A little pool
of water immediately formed upon the carpet, which I had no sooner
noticed, than I got up to remove the _parapluie_ to its proper place in
the stand, but started back in surprise, for in the little pool stood
the fugitive fiddler moistening his branchiæ.
Taking up the little prodigal who had left my protection so lately,
I soon deposited him in a vase of clear salt water. After a while,
thinking it might conduce to the happiness of both parties, I placed
him in companionship with his old friend, _Carcinus mænas_. This,
like many other philanthropic projects, proved a complete failure.
Both creatures, once so harmless towards each other, seemed suddenly
inspired by the demon of mischief. Combats, more or less severe,
constantly occurring, in a few days I separated them.
The 'fiddler' I placed in the large tank, where he rested content, and
never again offered to escape--evidently the better of his experience.
Not so his old friend, who still continued obstinate and miserable as
ever. In his case I determined to see if a certain amount of sternness
would not curb his haughty spirit. For two days I offered him no
food, but punished him with repeated strokes on his back, morning and
evening. This treatment was evidently unpleasant, for he scampered
about with astonishing rapidity, and ever endeavoured to shelter
himself under the granite centre-piece. When I thought he had been
sufficiently chastised, I next endeavoured to coax him into contentment
and better conduct. My good efforts were, however, unavailing. Every
morning I placed before him a newly-opened mussel, but on no occasion
did he touch a morsel. All day he continued struggling, as heretofore,
to climb up the side of his chamber, trying by every means in his power
to escape. This untameable disposition manifested itself for about a
week, but at the end of that time, on looking into the vase, I saw
the crab seated on the top of the stone, his body resting against the
glass. I then took up a piece of meat and placed it before him. To my
surprise he did not run away as usual. Having waited for some minutes,
and looking upon his obstinacy as unpardonable, I tapped him with a
little stick--still he never moved. A sudden thought flashed across my
mind; I took him up in my hand, examined him, and quickly found that he
was stiff and dead!
* * * * *
There is a little crab, _Porcellana longicornis_, or Minute
Porcelain-Crab, frequently to be met with in certain localities.
The peculiarity of this creature is the thickness and the great
disproportionate length of his arms, as compared with the size of his
pea-like body. He possesses a singular habit which I have not observed
in any other crustaceans. He does not sit under a stone, for instance,
but always lies beneath such object with his back upon the ground;
so that when a boulder is turned over, these crabs are always found
sitting upon it, whereas the shore-crabs, when the light of day is
suddenly let in upon them, scamper off with all possible speed; or if
any remain, it appears as if they had been pressed to death almost, by
the weight of the stone upon their backs.
The colour of _P. longicornis_ is that of prepared chocolate, shaded
off to a warm red.
Another crab, equally common with those already mentioned, is to
be met with when dredging, and in most rock-pools. At Wardie, near
Edinburgh, I have seen hundreds of all sizes hiding beneath the rocks
at low tide. Its scientific name is _Hyas araneus_, but it is better
known as one of the Spider-Crabs. It claims close relationship with
that noted crustaceous sanitory reformer, _Maia squinado_. Although
this H. araneus is a somewhat pleasant fellow when you get thoroughly
acquainted with his eccentricities, appearances are sadly against him
at starting. Speaking with due caution and in the gentlest manner
possible, consistent with truth, I must say that this crab is, without
exception, one of the dirtiest-looking animals I have ever met with in
my zoological researches. At a by no means hasty glance, he appears to
be miraculously built up of mud, hair, and grit on every part, except
his claws, which are long and sharp as those of any bird of prey.
The first specimen I ever saw, seemed as if he had been dipped in a gum
pot, and then soused over head and ears in short-cut hair and filth.
The second specimen, although equally grimy, had some redeeming points
in his personal appearance, for at intervals every part of his back and
claws were covered with small frondlets of ulva, dulse, _D. sanguinea_,
and other beautiful weeds, all of which were in a healthy condition.
After keeping him in a vase for a week, he managed, much against my
wish, to strip himself of the greater part of these novel excrescences.
Instead of minute algæ, we read that these crabs are sometimes found
with oysters (_Ostrea edulis_) attached to their backs. Mr. W. Thompson
mentions two instances where this occurs, with specimens of _H.
araneus_, to be seen in Mr. Wyndman's cabinet. Speaking of these, he
adds, 'The oyster on the large crab is three inches in length, and five
or six years' old, and is covered with many large Balani. The shell,
a carapace of the crab, is but two inches and a quarter in length,
and hence it must, Atlas-like, have born a world of weight upon its
shoulders. The presence of the oyster affords interesting evidence that
the Hyas lived several years after attaining its full growth.
For days after I had brought him home, my second specimen appeared as
if he were dead, and it was only by examining his mouth through a hand
lens that I could satisfy myself as to his being alive. When I pushed
him about with an ivory stick he never resisted, but always remained
still upon the spot where I had urged him.
This species of _acting_ he has given up for some time, and at the
present moment I rank H. araneus among my list of marine pets, for he
does not appear any longer to pine for mud with which to decorate his
person, but is quite content to 'purge and live cleanly' all the rest
of his days.
The ancients imagined that _Maia squinado_ possessed a great degree of
wisdom, and further believed him to be sensible to the divine charms
of music. It is very curious, as well as true, that this animal has
in a far higher degree than other crustaceans, a gravity of demeanour,
and a profound style of doing everything, that always excites our
irreverent laughter, but at the same time leaves an impression that,
if justice were done, the animal ought to hold a higher position in
the marine world than a scavenger and devourer of ocean garbage. If
_Maia_ and _C. mænas_ be both eating out of the same dish, in the shape
of an open mussel, the former seems ever inclined to admonish his
companion upon greediness and want of manners. The only seeming reason
why _M. squinado_ does not really give such advice, is because of the
impossibility of any individual speaking with his mouth full. The
knowledge, too, that if he commenced a pantomimic discourse, it would
give his young friend an opportunity of gaining too large a share of
the banquet, may, perhaps, have something to do with his preferring to
remain quiet.
As for _Maia's_ possession of appreciative musical qualities, I can
only state that both he and his friend _Hyas_ really do convey to
the beholder an impression confirmatory of this statement. I have
frequently been amused to observe the singular phenomenon of each
animal coming to the side of the vase and rocking his body to and fro,
in apparent delight at the exercise of my vocal abilities, just as
when a pleasing melody is being played in the concert room, we bend
backwards and forwards, and beat time to the tune. These animals also
adopt the same course: it must be to unheard music (which the poets say
is sweetest), that seems ever and anon to fall on their ears, giving
them great delight.
The movements here alluded to may be in no way influenced by music; but
such as they are, it is curious that they have not been noticed as an
apparent explanation of the origin of the ancient belief regarding the
Spider-Crabs.
* * * * *
A friend, on one occasion having procured for me, among other objects,
a Common Limpet, I placed this mollusc in my aquarium, and soon had
the pleasure of watching it affix its broad foot to the surface of the
glass. After a while, on the Limpet slightly raising its canopy, I was
surprised to observe a little Shore-Crab peer out from between the foot
and shell. On suddenly ejecting the intruder by means of a small brush,
he speedily hid himself from view among the surrounding pebbles. A few
hours after, on again approaching the tank to view the Patella (which
was easily identified, from the fact of an immense colony of Mussels
being settled on its back), I found to my great astonishment that the
crab had re-seated himself in his old position. I often repeated the
sweeping operation, but without success, for the little rascal had
become artful, and was not inclined to be driven forth a second time
by a _coup de main_. I touched the Limpet frequently and saw it glue
itself, as usual, to the glass; but, singular to state, the creature
always left a larger space between its foot and the circumference
of the shell on the side at which the crab was seated, than on the
opposite one, seemingly from a wish to accommodate its crustaceous
friend. This space, moreover, let me observe, was larger than was
absolutely necessary, for, as the shell was not air-tight, I was
enabled to thrust my camel-hair pencil teazingly upon the crab, and was
much amused to watch him clutch at the intruding object, and, at times,
move about with it in his grasp, thus proving that he was by no means
uncomfortably 'cabin'd, cribb'd, confin'd.'
For a whole week the crab remained in his favorite lodgings, and only
resigned occupancy thereof when his friend gave up the shell--and died.
There is a certain species of crab, _Pinnotheres pisum_, or common
Pea-Crab, frequently found in _Mytilus edulis_, the Oyster, and the
Common Cockle. Indeed, one gentleman states, that on his examining, on
two occasions, a large number of specimens of the _Cardium edule_, he
found that nine out of every ten cockles contained a crab. Still, in no
other instance than the one my own experience furnishes, have I ever
heard of the Shore-Crab, or, indeed, of any other crustacean, becoming
the guest of _Patella_.
The classical reader will not fail to remember Pliny's statement
(somewhat analogous to that above narrated) of a small crab,
_Pinnotheres veterum_, which is always found to inhabit the Pinna,--a
large species of mussel. This latter animal being blind, but muscularly
strong, and its juvenile companion quick-sighted, but weak of limb, the
crab, it is said, always keeps a sharp look-out, and when any danger
approaches, he gladly creeps into the gaping shell for protection. Some
writers assert, that when the bivalve has occasion to eat, he sends
forth his faithful henchman to procure food. If any foe approaches,
_Pinnotheres_ flies for protection with his utmost speed to the anxious
bosom of his friend, who, being thus warned of danger, closes his
valves, and escapes the threatened attack. When, on the contrary, the
crab loads himself with booty, he makes a gentle noise at the opening
of the shell, which is closed during his absence, and on admission,
this curious pair fraternize, and feast on the fruits of the little
one's foray.
For those of my readers who may prefer verse to prose, I here append a
poetical version of this fable--equally pretty, but, let me add in a
whisper, equally opposed to fact, at least in its principal details:--
'In clouded depths below, the Pinna hides,
And through the silent paths obscurely glides;
A stupid wretch, and void of thoughtful care,
He forms no bait, nor lays no tempting snare;
But the dull sluggard boasts a _crab_ his friend,
Whose busy eyes the coming prey attend.
One room contains them, and the partners dwell
Beneath the convex of one sloping shell:
Deep in the watery vast the comrades rove,
And mutual interest binds their constant love;
That wiser friend the lucky juncture tells,
When in the circuit of his gaping shells
Fish wandering enters; then the bearded guide
Warns the dull mate, and pricks his tender side.
He knows the hint, nor at the treatment grieves,
But hugs the advantage, and the pain forgives:
His closing shell the Pinna sudden joins,
And 'twixt the pressing sides his prey confines.
Thus fed by mutual aid, the friendly pair
Divide their gains, and all their plunder share.'
There is one singular feature in the Crustacea which it may prove
interesting to dwell a little upon. I allude to their power of living
apparently without food, or at least without any other sustenance
than is afforded by the animalculæ contained in the water in which
they dwell. One accurate observer states that he kept a Cray-fish for
a period of two years, during which time the only food the animal
received was a few worms,--not more than fifty altogether. This
statement I have often had ample means of verifying. Yet, on the other
hand, strange to say, the crab is always on the hunt after tit-bits;
and nothing seems to give him greater delight than a good morning meal,
in the shape of a newly opened Mussel, Cockle, and above all--a Pholas.
Let a youthful crustacean cast its shell, and rest assured, unless its
companions have had their appetites appeased, they will endeavour to
fall upon and devour the defenceless animal. This, to my chagrin and
annoyance, I have known to occur repeatedly. When nothing else can be
procured, not only the Lobster Crabs, but any Brachyurous Decapods
who may be at hand, will set to work, and industriously pick off and
eat the Acorn-Barnacles attached to any object within reach. These
facts show that the asceticism of the crab is not voluntary, and that
when opportunity occurs, he is as fond of a good dinner as are animals
possessed of a higher degree of organization.
It will be gratifying if other observers are able to verify the
circumstance which I shall allude to hereafter, and which would seem
to show that the _exuviation_ of crustacea is expedited by affording
specimens an unlimited supply of food.
'The organs for pursuing, seizing, tearing, and comminuting the food of
the Brachyurous Decapods,' says Professor Bell, 'are carried to a high
degree of development; ... these appendages consist of six pairs, of
which some are actual organs of mastication, as the mandibles or the
true jaws, the foot jaws or pedipalps, generally serving to keep the
food in contact with the former, whilst it is being broken up by them.
'The buccal orifice in the Brachyura occupies the interior face of
the cephalic division of the body, and is bounded anteriorly by a
crustaceous lamina of determinate form, which has been termed the upper
lip, and posteriorly by another, termed the lower lip. The mandibles
occupy the sides of the opening. After these, and external to them,
are the first, and then the second pair of true jaws, followed by the
three pairs of pedipalps or foot jaws, the last of which, when at rest,
close the mouth, and include the whole of the preceding ones. In the
Macroura the pedipalps are very different in their forms, and have the
aspect of very simple feet.
'The means of comminuting the food are not restricted to the
complicated machinery above referred to, for the stomach itself
contains a very remarkable apparatus, consisting of several hard
calcareous pieces, which may be termed _gastric teeth_. They are
attached to horny or calcareous levers, fixed in the parietes of
the stomach; they are moved by a complicated system of muscles, and
are admirably adapted to complete the thorough breaking-down of the
aliment, which had already been to a considerable extent affected by
the buccal appendages. These gastric teeth may be readily seen and
examined in the larger species of Decapoda, as in the large eatable
crab and the lobster; and it will be readily perceived how perfectly
the different pieces are made to act upon each other, and to grind the
food interposed between them.'
Having been on a certain day at the sea-side collecting, I was amused
to observe the movements of two ragged little urchins, who approached
near to where I stood, bottle in hand, examining some beautiful
zoophytes by aid of a pocket lens. One of them had a short iron rod,
with which he very dexterously hooked out any unfortunate crab who
happened to have taken up its quarters in some crevice or beneath
a boulder. Having captured a specimen, it was handed over to his
companion, who quickly tied it to a string which he held in his hand.
I had seen many a rope of onions, but this was the first time I had
seen a rope of crabs. On inquiry, I learned that the boys had taken two
dozen animals in about two hours. When any of the green-bellied crabs
happened to be poked out, they were allowed to escape back again as
quickly as they pleased.
With poor _Cancer pagurus_ the case was different,--every specimen, as
soon as caught, being strung up, and doomed to 'death in the pot.'
The above, I need scarcely state, is not the usual manner of fishing
for crabs, the approved plan being to take them in what are termed
crab-pots, 'a sort of wicker-trap made, by preference, of the twigs of
the golden willow (_salex vitellina_), at least in many parts of the
coast, on account, as they say, of its great durability and toughness.
These pots are formed on the principle of a common wire mousetrap, but
with the entrance at the top; they are baited with pieces of fish,
generally of some otherwise useless kind, and these are fixed into the
pots by means of a skewer. The pots are sunk by stones attached to the
bottom, and the situation where they are dropped is indicated, and the
means of raising them provided, by a long line fixed to the creel, or
pot, having a piece of cork attached to the free end of the line; these
float the line, and at the same time serve to designate the owners
of the different pots--one, perhaps, having three corks near together
towards the extremity of the line, and two distant ones--another may
have one cork fastened crosswise, another fastened together, and so
on. It is, of course, for their mutual security that the fishermen
abstain from poaching on their neighbour's property; and hence we find
that stealing from each other's pots is a crime almost wholly unknown
amongst them.'
'The fishery for these crabs constitutes an important trade on many
parts of the coast. The numbers which are annually taken are immense;
and, as the occupation of procuring them is principally carried on
by persons who are past the more laborious and dangerous pursuits of
general fishing, it affords a means of subsistence to many a poor man
who, from age or infirmity, would be unable without it to keep himself
and his family from the workhouse.'[3]
[3] Bell's Brit. Crus.
CHAPTER V.
Hermit-Crabs.
'Finding on the shoar
Som handsome shell, whose native lord of late
Was dispossessed by the doom of Fate,
Therein he enters, and he takes possession
Of th' empty harbour, by the free concession
Of Nature's law--who goods that owner want,
Alwaies allots to the first occupant.'
DU BARTAS.
[Illustration:
1 COMMON HERMIT-CRAB (_Pagurus bernhardus_) in shell of common Whelk
2 COMMON HERMIT-CRAB out of shell
3 SHIP BARNACLES]
V.
Twice in every twenty-four hours the waters of the ocean ebb and flow.
Twice only in each month, however, do the spring-tides occur. For there
are few dangers that the ardent student of nature would not encounter.
Lord Bacon tells of a certain bishop who used to bathe regularly twice
every day, and on being asked why he bathed thus often, answered,
'Because I cannot conveniently bathe _three_ times.' The zoologist,
like the 'right reverend father' alluded to, would willingly undergo
what appears to others much hardship and trouble, not only once or
twice, but even three times daily, in pursuit of his favourite studies,
did Nature but offer the kind convenience.
On these occasions the zoologist can pursue his researches at the
shore, at a distance beyond the usual tidal line. Numerous boulders and
rock-pools, during many days covered by the sea, being then laid bare
and exposed to his eager, searching hands and eyes, he is frequently
able to discover many rare objects, or, at least, common ones
revelling in almost giant-like proportions, and wonderful profusion.
The Soldier or Hermit-Crabs (to an account of whom we intend to devote
this chapter), offer a most remarkable proof of this. Occupying the
centre of a rocky excavation, I have repeatedly found several dozen
of these comical creatures, each inhabiting the cast-off shell of a
defunct Whelk (_Buccinum undatum_), which measured not less than five
or six inches in length. To my surprise these aldermanic crustaceans
possessed no companions of a smaller growth; while at a few yards
nearer shore, as many shells would be found congregated together as in
the more distant pool,--the largest, however, being no bigger than a
damson, while the smallest might be compared to an infantile pea, or
cherry-stone.
I cannot explain this appearance otherwise, than by supposing that
the _Anomoura_ become prouder, or, it may be, more cunning, as they
grow older, and, having arrived at their full development, they
fit themselves with their final suit; thereafter, in a spirit of
aristocratic exclusiveness, they retire to fashionable subaqueous
residences, distant as far as possible from the homes of the
_canaille_, who inhabit the common, littoral boundaries of the shore.
The peculiarity, to which I alluded, of the _Anomoura_ occupying
shells that have formerly belonged to other animals, is so strange
that some writers have not hesitated to express doubt upon the
subject. This denial of a fact, which can so readily be proved, is one
of the 'curiosities of literature.' Swammerdam, a Dutch naturalist
contemptuously observes, 'What an idle fable that is which is
established even among those who study shell-fishes, when they show
some kind of the crab kind in their museums, adding at the same time,
that they pass from one shell to another, devour the animals that
lived in those shells, and keep them for their own habitations. They
dignify them with the high-sounding names, and additions, as Soldiers,
Hermits, and the like; and thus, having no experience, they commit
gross errors, and deceive themselves, as well as others, with their
idle imaginations.'
That there is nothing mythical in the matter can easily be made
apparent to any person who chooses to visit the sea-shore. At such
locality he need have no difficulty in recognising the Hermit-Crab, or
meeting with numerous specimens for examination. Supposing such a one
is at a rock-pool, and, moreover, that he knows by sight the Buckie
(periwinkle), and Common Whelk, he will probably in such case be aware
that the animals occupying these shells are snail-like in construction,
and that their locomotion is consequently slow and formal. If,
therefore, when peering into any pool he sees the Buckie, for instance,
apparently change its nature, and instead of
'Dragging its slow length along,'
scamper off suddenly, or roll over and over from the top of an
eminence to the bottom, he may rest assured that the original
inhabitant has departed, and that its place is occupied by a
Lobster-Crab.
The cause of his strange peculiarity I will briefly explain.
In the true Lobster the tail forms a most valuable appendage. In the
tail the principal muscular power of the animal is seated; and by means
of it, too, the animal is enabled to spring to a considerable distance,
and also to swim through the water at will. This important organ is
well protected by a casing consisting of a 'series of calcareous rings,
forming a hard and insensible chain armour.'
In the Lobster-Crab there is no such arrangement. 'The abdominal
segment of this singular animal, instead of possessing the same
crustaceous covering as the rest of his body and claws, is quite
soft, _and merely enveloped in a thin skin_. To protect this delicate
member from the attacks of his voracious companions, the poor Pagurus
is compelled to hunt about for some Univalve, such as a Whelk or
Trochus, and having found this, he drops his tail within the aperture
and hooks it firmly to the columella of the shell. Why Providence
has doomed the poor Hermits to descend to such physical hypocrisy,
and clothe themselves in the left-off garments of other animals, it
is not easy to conjecture. No doubt, besides the defence of their
otherwise unprotected bodies, he has some other object of importance
in view. Perhaps they may accelerate the decomposition of the shells
they inhabit, and cause them sooner to give way to the action of the
atmosphere; and as all exuviæ may be termed nuisances and deformities,
giving to these deserted mansions an appearance of renewed life and
locomotion, removes them in some sort from the catalogue of blemishes.'
Professor Jones, when treating of this class of animals, forcibly
remarks that 'the wonderful adaptation of all the limbs to a residence
in such a dwelling, cannot fail to strike the most curious observer.
The _Chelæ_, or large claws, differ remarkably in size, so that when
the animal retires into its concealment, the smaller one may be
entirely withdrawn, while the larger closes and guards the orifice. The
two succeeding pairs of legs, unlike those of the Lobster, are of great
size and strength, and instead of being terminated by pincers, end in
strong-pointed levers, whereby the animal can not only crawl, but drag
after it, its heavy habitation. Behind these locomotive legs are two
feeble pairs, barely strong enough to enable the Soldier-Crab to shift
his position in the shell he has chosen; and the false feet attached
to the abdomen are even still more rudimentary in their development.
But the most singularly altered portion of the skeleton is the fin
of the tail, which here becomes transformed into a kind of holding
apparatus by which the creature retains a firm grasp of the bottom of
his residence.'
So great is the power of the animals to retain hold of their shell, and
so intense their dislike to be forcibly ejected therefrom, that they
will often allow their bodies to be pulled asunder, and sacrifice their
life rather than submit to such indignity. This fact I have proved
on sundry occasions. But supposing a crab to have taken a fancy to a
shell, occupied by some brother Pagurus, (a circumstance of frequent
occurrence), he quickly proceeds to dislodge the latter. Curious to
state, this process never seems attended with any fatal result.
When watching the operation, it has appeared to me as if the crab
attacked preferred to yield rather than be subjected to continuous
annoyance, and the discomfort of keeping for so long a time buried
within the inner recesses of his dwelling.
The contrast in appearance of the Hermit-Crab when seated in his shell,
and crawling about minus such appendage, is great indeed.
This the reader will readily perceive by examining the Illustrations on
Plate 4, which are drawn from nature, and are truthful portraitures of
this singular creature.
I have already mentioned the extreme difficulty there is in expelling
a Lobster-Crab. This, be it understood, applies only to the animal in
good health; for no sooner does he feel sick than he instantly leaves
his shell, and crawls about in a most pitiable plight. He sometimes
becomes convalescent again by being placed solus in some fresh water,
or laid out in the air for a few moments. But he ought, on no account,
when in a sickly condition, to be allowed to hide himself beneath any
pieces of rock or shadow of the Algæ.
If he is out of sight, be sure not to let him be out of mind; for,
should he die in the tank, and his body be allowed to remain for any
length of time, he will very soon afford you full proof that such
toleration on your part is anything but pleasant.
Although, as already stated, this animal cannot be drawn out of his
shell except by extreme force, the object can easily be obtained by aid
of strategy. Having been for some time at a loss how to give certain
young visitors a sight of the Hermit-Crab in his defenceless state, I,
by accident, hit upon the following simple plan:--
With a piece of bent whalebone I lifted up a Pagurus, shell and all,
and allowed the latter to drop upon the outer row of the tentacula of
an Actinia, which quickly stuck fast to the intruding object. The crab
at first did not seem fully alive to his critical position. He popped
out of his shell and looked unsuspectingly around, until catching
sight of my face, he instantly retired from view with a casket-like
snap. In a minute he was out again, and this time prepared to change
his position. For this purpose he gave several successive pulls, but
finding all his efforts to remove his carriage unavailing, he unhooked
his tail and scrambled down among the pebbles. My purpose was thereby
gained, for the next moment he was resting in the palm of one of my
juvenile friends, who seemed quite delighted with his prize. Twice
afterwards, being in a mischievous mood, I gave the crab a fright in
the way just mentioned; but it was quite evident, that what might be
sport to me was death to him, for he was both annoyed and alarmed at
my procedure. Even when guiltless of any intention of touching the
creature, if I merely showed him the cane he immediately hobbled away
at the utmost rate of speed he could muster. On several occasions I
followed after and brought him back to the edge of the tank, although
such conduct met with his strongest disapproval, and caused him for
some time to sulk beneath an arch-way of rock work, away from the reach
of vulgar eyes.
Upon the side and near the base of my tank a fine specimen of the
Limpet was at one time attached. From the centre of its shell a forest
of sea-grass waved gracefully, shadowing a large colony of Barnacles
thickly clustered beneath. Soon the Patella decided upon taking its
usual morning stroll in search of food, a task of little difficulty,
standing as the animal already did upon the margin of a broad meadow,
richly coated with a verdant growth, composed of the infant spores of
the Ulva. Slowly moving along, the Patella, with its riband-like band
of teeth, swept off the luscious weed in a series of graceful curves,
thus making an abundant and healthful meal. Before proceeding far,
however, he was forced to bear the weight of a Soldier-Crab, who had
most unceremoniously climbed upon his back, and taken up a position at
the base of the _latissima_ fronds.
There seemed so much nonchalance about the Pagurus that I determined
to watch his movements, and, if possible, to see how he would manage
to descend from a position which, if the mollusc continued his mowing
operations, would soon be unenviably high.
In about an hour the Limpet had reached the level of the water in the
aquarium, and there took up his abode for the night. Next day and the
next there was no change of situation. The crab now began evidently
to perceive the danger of the position in which he was placed, for he
constantly moved to and fro, and peered over into what must have seemed
to him an unfathomable abyss.
While I stood, the Patella made a sudden movement of its shell--so
sudden, indeed, as to startle its companion, who quickly put out his
claws to save himself from falling. Unfortunately, in his spasmodic
gesture he allowed the tip of one of his claws to intrude under the
edge of the conical canopy, thus, in fact, pricking the fleshy 'mantle'
of the animal within, who instantly, of course, glued itself to the
glass with immoveable firmness. I suppose the same thing must have
frequently occurred without my knowledge, for after a lapse of several
days the Pagurus and his bearer were still in the same spot. I felt a
growing alarm for the continued health of the Hermit-Crab, from the
fact of its being poised so directly over the ever-expanded tentacles
of a large Anemone. To prevent any mishap, I went to lift his crabship,
with a view of transferring him to a place of safety, when, no sooner
did he perceive the advancing forceps, than he rushed into his shell
with a sudden and audible 'click,' forgetting for the moment that he
stood on such ticklish ground. The consequence was that, seeking to
avoid Scylla, he fell into Charybdis. In other words, he dropped plump
upon the well-gummed tenter-hooks of the Crassicornis, which instantly
closed and engulphed its prize. In vain did I endeavour with all speed
to pick out the devoted Pagurus. The more I tried, the more firmly did
the Actinia hold him in its convulsive grasp.
With extremely few exceptions, the Hermit-Crabs are always found to be
a prying, prowling, curious class of animals, and are ever, like the
husband of the fair Lady Jane--
'Poking their nose (?) into this thing and that.'
They will turn over each shell and pebble that comes in their way, and
examine it with profound attention, or industriously climb up and roll
down hillocks and trees in the shape of small rocks and sea-weeds,
much to their danger.
I once possessed a Hermit-Crab, whose voracious movements afforded
considerable amusement to myself and my friends. My Diogenes--or,
as the Cockney news-boys used to pronounce the now extinct comic
periodical, _Dodgenes_--on a certain occasion had climbed up a
segmentally cut frond of Irish Moss. On reaching the topmost point, his
weight became too great for the weed to bear; so, finding he was losing
his equilibrium, in great alarm he made a clutch at the first object
that stood near, in order to save him from falling.
A mussel was moored hard by, to the side of the vase by means of its
silken byssus threads, and upon this friendly bivalve the Pagurus
leaped by aid of his long taper legs. Unluckily the shell of the
Mytilus was open, and the crab unwittingly thrusting his toe within the
aperture, the intruding object was of course instantly gripped by the
mollusc. This accident put him in a terrible fright. His gestures were
most excited, and no wonder. Let the reader fancy himself hanging on
to a window sill, at a height say of twenty feet from the ground, with
the sash-frame fixed on his hand, and a huge iron foot-bath, or some
such object, attached to the lower part of his body, and he will have a
tolerably correct idea of the painful position of our crustacean friend.
After curling and uncurling his tail, and trying several times in vain
to throw his tub upon the valve of the mussel, he released hold of his
encumbrance, and allowed it to drop. Although still hanging, he had no
difficulty in rolling up his 'continuation,' and elevating his body
to the walls of his prison. Once again upon solid ground, he laboured
hard to get his leg free. But unsuccessful in his efforts, he adopted
another course, and snapped it off in a rage.
Scarcely, however, was the act of mutilation finished, when the stupid
animal apparently seemed anxious to recover his lost toe, (which I may
mention, had in reality fallen down among the pebbles).
After scraping, then resting, and scraping again, many successive
times, he at last succeeded in diving the points of his largest claw
into the chasm formed by the gaping mollusc. Of course, the member was
held as if by a powerful vice. Very soon his courage deserted him, and
he seemed to wait and weep despairingly for fate to release him from
the sad predicament into which he had foolishly fallen. Alas! he little
knew the singular part that fickle fortune had doomed him to play,--to
become, if I may so term it, a kind of Prometheus in the tank.
My pack of fishes, having been on short rations for several days, had
become exceedingly ravenous, and consequently were keeping a sharp
look-out for scraps. Hence their intense delight on catching sight
of the devoted 'Dodgenes' can readily be imagined. Such a delicious
_morceau_ was perfectly irresistible:--
'Mercy, mercy!
No pity, no release, no respite, oh!'
At it they went, 'tooth and nail,' First one and then another tore away
a mouthful, until in the twinkling of an eye, almost, the martyr crab
was left forlorn and dead--
'A remnant of his former self.'
During the early portion of last year I had a Hermit-Crab inhabiting a
pretty Purpura, whose shell I wished to sketch as an illustration, it
being of peculiar form and colour. On going to the tank I discovered
that Pagurus had most apropos vacated his turbinated cot, apparently
in consequence of his feeling rather squeamish. Thinking he might
perhaps presently recover, or pick up another dwelling, I hesitated
not to abstract the shell, in order to make the required drawing. I
had not been occupied with my task for more than five minutes, when my
attention was attracted by a great excitement and clatter pervading the
tank. A hasty glance within the vessel sufficed to explain the cause of
the hubbub.
The brief domestic drama of which I was a spectator, with its somewhat
singular denouement, I will now proceed to unfold for the reader's
entertainment. It conveys a good lesson in natural history, and also
exhibits a striking example of life beneath the waters.
The Blennies, I may state, had become very voracious, pugnacious, and
audacious; nothing seemed safe from their attacks. I had begun to feed
them on the _Cardium edule_ and Mussel, but such diet, after a time,
only served to whet their appetite, which certainly appeared to 'grow
by what it fed on,' for they darted about through the water in all
directions, searching, as I suppose, for other dainties. These efforts
were unsuccessful, until they caught sight of the plump, undefended
portion of the body of their companion, the Hermit-Crab, who had just
left his shell, as above stated.
The sight of such a feast must have (figuratively speaking) made their
'mouths water,' One after another these rascally fish dodged round
the crustaceous victim, and gripped, and shook his 'continuation'
with extraordinary violence. In vain did the crab try to act on the
defensive; all his efforts to retaliate were ineffectual, and in this
instance it might be truly said that 'might' overcame 'right.' He ran
to and fro in great distress, scraping the pebbles and shells about
(thus partly creating the clatter that I had heard while sketching), in
the hope that he might find an empty univalve in which to deposit his
mutilated carcase. When almost breathless and exhausted, he discovered
a worn-out Wentletrap, and strove to lift his quivering body into the
aperture, alas! without success. His strength failed him, and he fell
dead at the very threshold of his new-found home.
While watching thus far the above transaction, the writer felt almost
inclined to waver in the faith he had long held with others, namely,
that fishes and other marine animals are insensible to pain. But
the movements of this poor Hermit-Crab were as indicative of severe
suffering as anything he ever witnessed in bird or quadruped.
Wishing to examine the remains of the crab, I stepped aside for a few
moments to procure my forceps, but when I again reached the vase, to
my intense surprise the defunct animal was nowhere to be seen! I could
only account for so singular a circumstance by supposing some of the
larger crustaceans had taken advantage of my absence to complete the
work of destruction, and therefore took no further notice of the matter
at the time.
I had often wished that some of my finny pets would deposit their spawn
in the tank, and felt very anxious, if such an event did take place,
that I might be near to witness it. But I was most anxious to watch the
gradual development of the ova, and, if practicable, to become the fond
owner of a host of infant 'fishlings.'
Guess the thrill of pride, then, which ran through my veins when, on
peering into my mimic rock-pool, after a brief absence from home, I
observed the largest of my Blennies to be apparently in an 'interesting
condition.' I watched and petted her many times daily, and fed her with
every suitable dainty that could be thought of. Sometimes I took her
in the palm of my hand, and with a fine camel-hair pencil stroked her
glossy back. This operation evidently gave great delight to the little
beauty; and after a while, when my hand was laid in the water, she
gently floated off into her native element with almost swan-like grace.
The law of nature being the same with this fish as with the
Stickleback, I knew the nest, if there was to be one at all, should
be built by the male. But as I could not detect any specimen of the
'sterner sex' among my pack, and there being no signs of preparation
for the grand event about to take place, I felt in a manner compelled
to carry out the nidifying task in my own humble way. Of course, I gave
up all idea of 'weaving' a nest with bits of weed, stones, and marine
glue; nor was such a style of structure a desideratum in the present
instance, wanting, as I did, to take notes, in Paul Pry fashion, of the
minutest particular that might occur within the building. The following
was the plan I adopted. First was procured the exquisitely formed valve
of a large _Pecten_, the interior of which was white and beautifully
irridescent. This pretty cot, I said to myself, shall serve as a
chamber for my _protégé_. The shell being deposited behind a piece of
rock, in such a position that its side rested against the surface of
the glass, I was thus enabled to watch what was going on within. Some
fronds of sea-weed were trained around so as to form a kind of drapery.
The Blenny, I am quite certain, knew perfectly well that all this care
and preparation was on her account, for nearly the whole of each day
she spent in the novel apartment extemporized for her accommodation.
After a week had elapsed, she grew uneasy and pettish, was ever
snapping at her companions, and hunting them about in all directions.
On one occasion, however, she seemed to be uneasy, now clashing round
the rock, then darting to the top of the tank, and down again upon the
pebbles. Scores of times these movements were repeated, until I felt
alarmed for her safety, and annoyed at my inability to relieve her
sufferings. But aid from me being impossible, I felt compelled, though
very unwillingly, to allow nature to take its course.
On looking into the aquarium one morning, I observed some strange
object protruding from the fish. The little creature, too, on catching
sight of me, came to the side of the tank, near to where I stood, and
by her movements asked me, as plainly as any dumb animal could ask, to
give her my assistance. After a few minutes spent in a 'brown study', I
resolved to grant her petition, and immediately setting to work, drew
from her--what? what do you suppose, reader? In truth neither more nor
less than the body, head, and long antennæ of the 'martyr' Hermit-Crab!
whose late sudden disappearance was now fully accounted for.
There are ten British species of Lobster-Crab, but one only, _P.
Bernardhus_, to which the reader has been introduced, is common to our
shores.
CHAPTER VI.
Exuviation of Crustacea.
(THE PHENOMENA OF CRABS, ETC., CASTING THEIR SHELLS.)
'As Samson at his marriage propounded a riddle to his companions
to try their wits thereon, so God offereth such enigmas in Nature,
partly that men may make use of their admiring as well as of their
understanding; partly that philosophers may be taught their distance
betwixt themselves, who are but the lovers, and God, who is the giver
of wisdom.'--INTRODUCTION TO CONCHOLOGY, page 384.
VI.
The Armory of the Tower of London forms, it is generally admitted, one
of the most interesting sights of the great metropolis. No one can look
without wonder upon that goodly array of knights and noble warriors,
nor help an involuntary sigh over the degeneracy of modern humanity.
Though the figures before us are technically and irreverently termed
'dummies,' the hardened shell with which their body and limbs are
cased we know has felt the throb of many a true English heart, maybe,
glistened beneath the sun at Cressy and Agincourt, or perhaps on the
bloody fields of Worcester and Marston Moor. It requires no great
power of the imagination to transport ourselves to bygone centuries,
and listen to the ring of hostile arms, the sepulchral voices of men
whose heads are inurned in casques of steel, blended with the clash of
battle-axes, the whizz of arrows, the neighing of steeds, the rattle of
musketry, and at intervals the deep booming cannon's roar.
But, asks the gasping reader, what has this parade of mail-clad
warriors and old battle-fields to do with so prosaic a theme as the
exuviation of crabs? I must acknowledge that the question is a very
natural one, for there appears at first sight no connection between
the two subjects. The analogy will not, I believe, appear so forced
when I mention my possession of a smaller, although hardly less
singular armory, consisting of various coats of shelly mail, each of
which, at one time or other, belonged to, and was worn by a living
creature, and proved as effectual a protection in many fierce though
bloodless combats as any casque or helmet worn by knight. Unlike the
dummies of the Tower, my specimens are perfect, and give a complete
representation, more truthful than any photograph, of the defunct
originals, when armed by Nature _cap-a-pie_.
In plain words, I own a curious collection of the cast-off shells of
various crabs, which have from time to time been under my protection.
From the fact that no museum in the kingdom contains a single _series_
of such objects, exhibiting the various stages of growth in any
crustaceous animal, the reader will easily conceive the difficulty
there must be in procuring them, and consequently the interest that
attaches to the mysterious phenomenon of exuviation.
Strange to say, the subject of this chapter is one of the least known
in the whole range of natural history. The facts connected with the
process are few, and far from well authenticated. This state of things
appears the more extraordinary, when we remember the great facility
with which specimens of crustacea may be found.
For years past I have paid much attention to the elucidation of this
subject, and during that period have had to submit to numberless
mishaps and disappointments. For example, perhaps after watching a
'pet' day after day for months, anxiously expecting that exuviation
would take place, in nine cases out of ten,--ay, in ninety-nine out of
the hundred,--I would find that the process had been completed when
I was asleep, or that the animal had died suddenly. In the latter
case new specimens had to be procured, and the same watching process
repeated, in most cases with the like unhappy results.
I will now, however, endeavour as briefly as possible to make the
reader acquainted with what has already been written upon exuviation,
as far as I have been able to learn, up to the present time,
interspersing the narrative with such notes as may seem necessary by
way of illustration, and then proceed, in the words of Shakspeare, to
lay down my own 'penny of observation.'
The first clear and satisfactory remarks on this subject were made by
the celebrated Reaumur, who lived above a century ago: 'The unexampled
accuracy and truthfulness of this great naturalist is attested,' says
one writer, 'by the fact, that of all the observations made by himself
alone, far exceeding those of any other writer of past or present
times, and occupying in their published form numerous large quarto
volumes, scarcely one has been contravened by subsequent credible
observers, whilst they have formed the substance of half the numerous
compilations on insect life, acknowledged or otherwise, which have
appeared since his time.'
Goldsmith, who derived his knowledge of this subject from Reamur, tells
us, in his usual free and easy style, that crustaceous animals (as
crabs and lobsters) 'regularly once a year, and about the beginning of
May, cast their old shell, and nature supplies them with a new one.
Some days before this necessary change takes place, the animal ceases
to take its usual food. It then swells itself in an unusual manner,
and by this the shell begins to divide at its junctures between the
body and the tail. After this, by the same operation, it disengages
itself of every part one after the other, _each part of the joints
bursting longitudinally_, till the animal is at perfect liberty. _This
operation, however, is so violent and painful that many die under
it_; those which survive are feeble, and their naked muscles soft to
the touch, being covered with a thin membrane; but in less than two
days this membrane hardens in a surprising manner, and a new shell as
impenetrable as the former supplies the place of that laid aside.'
This, then, was and is to a great extent, up to the present time, the
universally adopted explanation. Goldie, of course, could not afford
time, and it may be doubted if he possessed the requisite amount of
patience, to confirm what he wrote by actual observation. Seeing that
the statement was graphic in its details, and evidently either wholly
or in part the result of personal observation, he very naturally
gave it full credence. But what shall we say of a noted writer (Sir
C. Bell)[4] who apparently half doubts the truth of exuviation, for
although he mentions the particular account which Reamur gives, yet
tells his readers that '_naturalists have not found these cast off
shells_.' After such a remark as this, we need no longer sneer at the
compilations of the author of the 'Vicar of Wakefield.'
[4] Illustrations to Paley's Natural Theology.
I need hardly state, that at certain seasons of the year almost every
rock-pool at the sea-shore will exhibit to the observant eye scores of
'these cast off shells' in a perfect state. The writer above quoted
also remarks, 'We presume the reason that the shells of the crustacea
are not found in our museums, is because they are not thrown off at
once, but that the portions are detached in succession.' An ill-founded
presumption this, the fact being that the inelastic integument is
invariably (in all the Decapoda at least) thrown off entire, the eyes
and long antennæ sheaths, the claws with the hair attached, even the
gastric teeth, all remain with wonderful exactness.
To look at the rejected shell, indeed, any person not previously
acquainted with the fact would naturally suppose that he saw before him
the living animal, a close inspection being necessary to dispel the
illusion. As soon as the crab has emerged from its old covering, it
increases with such astounding rapidity, that at the end of one or two
days it can grow no larger until the next moulting time.
In referring to my own introduction to the subject of exuviation, I may
be allowed to notice the annoyance a young aquarian experiences from
the rapidity with which the tank water is apt to become opaque. As such
a state involves considerable trouble, especially when the occupants of
the tank are the subjects of continued observation, I may mention, in
passing, that the means I adopted to correct this state of matters was
either to syringe the water frequently, or what seemed to answer still
better, to permit it to run off by a syphon into a basin on the floor.
When the opacity of the tank is occasioned by decaying animal matter,
the only remedy is to remove the offending 'remains.' But with many of
the common inhabitants of the tank--the crustaceans, for example--great
difficulty is often experienced in ascertaining their state of health,
with a view to sanitary investigation. As these creatures, instead
of boldly exhibiting themselves during the day, generally hide under
pebbles or pieces of rock, or are buried in the sand, it is sometimes
necessary to submit the contents of the mimic rock-pool to a process
of 'putting things to rights,' as the ladies say when about doing a
kindness,--oh, horror!--to our books and papers.
It happened on a certain occasion that my aquarium was in an
unsatisfactory condition. A nasty vapour arose from the base, and
diffused itself over nearly the entire vessel. My fishes disliking
their usual haunts, were all spread out at full length high and dry
upon a ledge of rock-work, projecting above the surface of the water.
The little Soldier-Crab had managed to drag his body and heavy tail
piece up the brae, hoping to breathe the fresh air in safety. His big
brother was not so successful, and despite his efforts speedily came to
grief. Finding he could not drag his carriage up the rock, he stepped
out of the lumbering vehicle. His appearance soon became woe-begone
in the extreme. In a few minutes he expired. The buckies, too, with
singular instinct, had collected in a row along the dry ledge of the
tank.
Upon counting the numbers of my little colony, I found all right,
excepting _C. mænas_; him I could not discover, and I soon began to
suspect that he was defunct. No time, therefore, was to be lost,
so a diligent search for his remains was instantly commenced.
Fishes, Buckies, Hermits, &c., were speedily placed in safety in
an extemporaneous tank--nothing else than an old pie-dish. This
receptacle, when partly filled with sea-water, admirably answered the
required purpose.
The water in the large vase was gently run off, and on approaching
the base I found, as I expected, the dismembered carcase of the
crab. One leg lay here, and another there, while the body was snugly
esconced beneath a stone, on which sat my favourite limpet with
its curiously formed shell, profusely decorated with a plume of
sea-grass and infantile _D. sanguinea_. Here, then, I thought, was
the mystery explained. It was from this spot that the noxious vapour
must have emanated. Of course, the body of the crab was removed; but
in performing this necessary act I tilted the stone, and so disturbed
the Limpet. Guess my surprise at observing the overturned shell of the
Patella to be quite empty, and its former occupant lying before me a
mass of putrefaction.[5] It now began to dawn upon me that I must have
libelled _C. mænas_. A few moments served to confirm this opinion, for
on lifting the stone, there darted out _a_--I could scarcely believe it
was _the_ crab, who instantly went through a circus-like performance
around the circumference of the vessel.
[5] This affords an important hint to the young aquarian to watch the
Patella, and occasionally to touch its conical house, to make sure the
proprietor is alive and well.
The reader will be prepared to learn that what I had at first observed
were portions of the exuvium, which had by some means been distributed
over the tank.
Many months did I wait with nervous anxiety to see the exact process of
exuviation, but, except in the instances I am now about to chronicle,
my wishes were never gratified.
I had at one time in my possession six little vases, each containing a
crab measuring about one inch across the back (_carapace_). By constant
watchfulness, morning and evening, for several months, I naturally
entertained a confident hope of being favoured with a sight of the
moulting operation in at least a single instance. But no; persevering
though my endeavours were, I was always disappointed. The exuviæ were
cast regularly enough, but the crabs so managed matters, that the
process was completed either when I was asleep, or had just gone away.
I could almost have sworn that the whole pack had entered into a league
to annoy me.
On one occasion I sat up all night, feeling confident, from symptoms
which a certain Cancer mænas exhibited, that he was speedily about to
exuviate. Alas! I was mistaken. On my endeavouring to expedite the
event by lifting up the carapace of the crab, I received a nip on my
finger so severe, that I shall never forget it.
But at length in the early portion of last year (1859), I, most
happily for my own peace of mind, did actually witness the entire
process of exuviation in a tolerably large specimen of the Common Shore
Crab. The animal in question, who was domiciled in a crystal vase,
or, in common language, a glass tumbler, rendered himself a favourite
from his constant habit of poking part of his head and his entire
claw (he had got but one), out of the water whenever he caught sight
of me. Who could resist such a powerful, though silent appeal to 'the
generous impulses of one's nature' as this? Certainly I could not,
and therefore, once a day at least, gave Master Cancer the half of a
newly-opened mussel, a tit-bit that was greatly relished. He would
sometimes get a grip of the valve, and allow himself and the Mytilus
to be entirely raised out of the water. Improving upon this, he would
then partly finish his meal while seated in my hand. On the morning
of the above mentioned eventful day, I gave the crab a portion of a
Pholas, but to my surprise, the heretofore high-class dainty remained
untouched. I was in ecstasies! for I felt morally certain that the
grand event, so long looked for, was soon to take place. Consequently,
I took out the crab, cleaned the windows of his dwelling in order
that I might the better see what was going on within, treated him to
some fresh water, as well as a new frond of sea-weed, and then again
introduced my pet to his old apartment.
Before doing this I had the animal closely examined, to see if any
signs of the approaching moult could be detected, but none were
visible, except that the glassy bags, if I may so call them, which for
some weeks had been gradually thrown out from the stumps of the three
mutilated limbs, appeared finer in texture than usual. Indeed, so
transparent had they become, that I could distinctly see the contour of
the new limb about to be reproduced, folded up within each capsule.
A few minutes after the crab had been placed in the tumbler, I gave a
peep to see how he was getting on. To my intense surprise, I observed
that his shell had just opened near the tail! My first feeling was
one of sorrow, thinking that in handling the specimen I had been too
rough, and had perhaps injured it. This apprehension was soon changed
to delight, as I became by degrees aware that exuviation had actually
commenced.
The operation did not extend beyond five minutes (although the time
appeared much longer to me), and was carried on by gentle, and at first
almost imperceptible degrees. The shell, or carapace, was slowly raised
over the back, and gave one the idea of the rear view of a lawyer's
white wig when tilted over his brow, thus exposing the natural black
hair on the occiput below; for, as the body of the animal came forth,
it was very dark in colour, while the old case assumed a whitish hue.
I need hardly say, the leg sheaths of the crab did _not_ split open,
and yet the corresponding limbs were drawn out with the greatest ease.
Moreover, they did not appear in view one by one, but in a cluster, as
it were, and packed close to the bent body of the crab.
During the entire process the animal appeared to use scarcely any
exertion whatever, certainly not half so much as any human being would
exhibit in throwing off the most trifling garment. In fact, the crab
seemed to swell painlessly, and gently roll or glide out in a kind
of ball. Until it had completely escaped from its old shell, I was
somewhat puzzled to guess what shape it would eventually assume. The
eyes and antennæ, so soon as they left their old sheaths, commenced,
together with the flabellæ, to work as usual, although as yet they were
still inside the exuvium. This circumstance was distinctly visible by
looking through the side of the half-cast shell.
It was a curious and extraordinary sight to see the eyes gradually lose
their brilliancy, and exhibit the filmy, lack-lustre-like appearance of
death, while the act of exuviation was being accomplished. I may add
that the tumbler which held my little captive stood upon a table near
a large window, and that the sloughing operation was watched through a
powerful hand lens.
On an after and well-remembered occasion, I saw a moderate-sized
Partane standing on the top of a bush of _Chondrus Crispus_ that grew
in my aquarium. The fronds were attached to a piece of sandstone,
placed uppermost upon a cluster of rock-work, situated, as before
mentioned, in the centre of the vessel, and rising slightly above the
level of the water. Thinking he was planning means of escape, I turned
away for a few moments to procure a simple instrument wherewith to
carry him to a less elevated position. On my return I saw him in the
act of backing out of his shell. It was a singular circumstance that
I should have just risen from the perusal of a talented author, who
informed me that 'the crab hitches one of its claws into some crack or
fissure, and from this point of resistance gives more power in emerging
and withdrawing itself from between the carapace and the tail.'
Certainly no statement could more inadequately describe what I had
witnessed in both of my crabs. Not only was the whole operation
performed with perfect ease, but I am much inclined to believe with a
degree of pleasure. For a while one of my crabs stood in juxtaposition
to the shadow of its former self, and rubbed his antennæ and wee
peeping eyes as if awakening from a sleep. He had been lately, there
was no doubt, living in an oppressed state, and might probably have
surveyed things around him somewhat darkly, but now all was bright and
clear again. On turning, the first object that caught his awakened
eye was his cast-off vestment, which he seemed to scan as dubiously
as a grown man would an exhumed pair of boyish corduroys, and mutter
musingly, while stroking his chin, 'Well, come what will, it can never
be my _case_ again.'
On taking it in my hand, the Partane felt quite soft and velvetty to
the touch, and exhibited no signs of alarm.
Since then I have repeatedly had shells of crabs cast _in smooth glass
globes, containing nothing else but clear salt water_. This fact, in
my opinion, completely subverts the statements of certain writers, who
assert that these animals require extraneous assistance when about to
exuviate.
Some writers have questioned the truth of the generally-received
opinion that the new parts of the crab are derived from the old: that,
for instance, a claw is regenerated within a claw, a limb within a
limb, eyes within the eyes, and that on exuviation each is withdrawn
from the pre-existing organ as from a sheath. But my operations tend
fully to confirm the popular and existing belief.
There is yet one curious point connected with this subject which
requires explanation, as it is not generally understood. I allude to
the apparent disproportionate smallness of the 'glassy bag,' situated
at the stump, as compared with the size of the regenerated limb, which
is supposed to be folded up within the bag previous to exuviation.
On looking at the newly-formed member, we can scarcely believe it
possible that the transparent case could by any possibility have held
it. The mystery vanishes if the new limb or claw be examined; for,
although in shape it is perfect, even to the most minute particular, it
remains for a certain period comparatively useless to the animal, from
the fact of its being utterly devoid of flesh.
The new limb, therefore, can be considered merely as an expanded case,
which, by a wonderful law of nature, becomes slowly filled up and
completed. Immediately after exuviation has taken place, and a claw is
introduced in the place of some mutilated stump, if any one will pull
off the new member, he can readily confirm the truth of what I have
stated, and, moreover, be able to test into how very small bulk the new
limb may be rolled.
As the reader may remember, Goldsmith states that the crab casts its
shell 'regularly once a-year, at the beginning of May.' Professor
Owen fixes the date in the month of August. Professor Bell states,
that 'there is no doubt exuviation takes place _annually_ with great
regularity, until the growth is completed, which, in many species, is
not before the animal is many years old.' Another professor, treating
on the same subject, thus writes, 'We are told that all this coat
of mail is _annually_ thrown off in a single piece by the contained
animal,--the great proficient in Chinese puzzles may well be posed at
this greater puzzle.' In fact, all writers whose works I have had
opportunity of examining repeat the statement. Mr. Ball, who writes
from personal observation, apparently confirms beyond a doubt, the
annual moult of Crustacea. This gentleman, we learn, kept a Cray-fish
alive for two years in a vase, and found that _during each year its
exuvium was shed but once_.
It may readily be believed, with such a formidable array of contrary
evidence, that I offer my own observations with modesty. But at the
same time, I feel justified in confidently stating that the moult of
the crab, (in its comparatively youthful state, at all events), takes
place not only once, but many times during each year of its existence.
My specimens may, perhaps, be considered exceptions to the general
rule, but the facts I relate cannot by any possibility admit of doubt.
The cast-off shells lie before me as I write.
Here is a set of three belonging to the same animal, exhibiting with
marvellous exactness the gradual development of a broken claw. In the
first the member appears very diminutive, in the second it is nearly
twice its size, while in the third it has advanced to its natural form
and bulk. To my regret, I cannot state the exact period that elapsed
between each successive moult, but I am confident that the trio were
cast in the course of a very few months.
I may here take the liberty of informing the uninitiated, that the
appearance of the above objects is extremely pleasing; for, as the
exuvium becomes dry, its colour changes to a bright scarlet, somewhat
resembling that which the crab assumes when placed for a time in
boiling water.
The next series of specimens, five in number, possess even still
greater interest than the first examples. They were produced by a
youthful _C. mænas_, at the following consecutive intervals:--
The first moult took place on 11th April 1858; the second on the 22d
of May following; the third on July the 3d; the fourth on the 30th of
August; and the fifth on the 26th of September in the same year. So
that between the first and second period of exuviation there was an
interval of forty-one days, between the second and third forty-two days
elapsed, between the third and fourth fifty-eight days, but, singular
to state, between the fourth and fifth moult _only twenty-seven days
intervened_.
My first impression was, that as the creature grew older, its shell
would be renewed less frequently, and the dates of the sloughings
seemed to support this idea--until the fourth moult. It had occurred
to me that perhaps the operation might be accelerated by the amount
of diet which the crab consumed. In order to test this, I fed the
animal carefully every day, as though he were a prize beast about to be
exhibited at some Christmas show. Nothing loath, he ate of everything
that was placed before him with a gusto that would have done credit to
an alderman. The result was, that the shell was renewed in less than
half the time that elapsed between the preceding moults.
These interesting investigations, which had been conducted thus far so
satisfactorily, were suddenly brought to a close by the death of my
protégé. This sad event occurred unexpectedly, not from overfeeding, as
some persons may suppose, but from natural causes.
Whether increase of food always produces a like effect to that
mentioned, is a point that I hope some of my brother naturalists will
be able to determine. That the moult was accelerated by such means
in my own specimen I have not the slightest doubt, for, on no other
grounds can I explain its unusually speedy occurrence.
I may here assure my readers that the above dates may be confidently
relied upon as correct, and also that each exuvium was produced by the
same crab--one specimen only being in the tank during the whole period.
Since the foregoing was written, I have again been fortunate enough to
have ocular demonstration of the phenomenon of exuviation, as occurring
in a _Cancer Pagurus_, about as large as a moderate-sized walnut.
While watching this crab, it flashed across my mind that it would be a
happy circumstance if by any means _I could arrest the process then
going on before my eyes, while it was yet only half completed_, in
order that others might also be enabled to witness the marvellous act
of exuviation.
But how to carry out this scheme was the rub. I knew that--
'If 'twere done, then 'twere well it were done quickly.'
One minute passed,--two minutes flew by;--the crab would speedily
complete his labours; still was I perplexed.
To plump it into fresh water would, I knew, be fatal to the animal,
but not in such a speedy manner as was desirable. Boiling water next
suggested itself, and doubtless would have answered the purpose
effectually, had a supply been near at hand at the time, but such was
not the case. I then thought of _spirits_. Ah! capital idea.... Before
the third minute had passed, I might be seen to rush frantically to the
sideboard, pour _something_ into a glass, then dart back to the tank,
dive down my trembling hand, bring up the poor unfortunate crab, and
drop it into a fatal pool of pure "Glenlivet."
The animal appeared to die quickly, and was next day transferred to a
vessel filled with Mythilated spirits. As it luckily turned out, the
whisky answered the intended purpose remarkably well.
The preparation in question is, as far as I can discover, _unique_; at
least I have neither read nor heard of another such existing in any
private or public museum in the kingdom.[6]
[6] A drawing of this crab will be found on Plate 3.
It shows at a glance the increase that instantaneously takes place
in the size of the crab after the act of exuviation is performed,
the portion exuded being on a scale considerably larger than the old
covering, which, however, is capacious enough to hold that half of the
animal that had not effected its deliverance at the moment when the
novel arrestment was so unceremoniously served.
The fourth and fifth pair of legs are free, while the eyes and antennæ
are also drawn out of their sheaths. (This is not very evident now,
but such is really the fact, I having distinctly seen those organs
in motion when the animal was in the living state.) The _chelæ_, or
large claws, being still undetached, serve to bind the crab to its old
integument, and thus enable the act of exuviation, or one phase of it
at least, to be distinctly apparent.
I know of no work on Natural History that speaks of the Hermit-Crabs
(_Anomoura_) casting their shells, and on this account I have given
some attention to them. These animals being so common, I kept by me at
least a dozen specimens for the purpose of observing some of them, if
possible, in the act of exuviation. The result of my labours has not
been so satisfactory as I could wish, from my not having been able to
collect any 'sets' of exuviæ. I cannot, therefore, speak with certainty
as to the frequency of this phenomena. By this time my readers will
know that the tail of the Hermit-Crab is very tender and fleshy, being
covered merely with an extremely delicate membraneous skin, while the
carapace, claws, and antennæ of the animal are protected by a hard
crust, similar to the Lobster, Cray-fish, &c.
From this peculiar formation of the crab, I was not at all surprised to
find, on several occasions, the upper part of its body alone cast off,
and therefore came to the very natural conclusion, that as the tail was
soft, it would grow and increase in proportion to the other parts of
the animal, without ever needing the skin to be changed.
Each morning and evening during the time my experiments were being
conducted, I examined all the tanks attentively, to see whether an
exuvium had been cast. If visible, the object was picked out and gummed
in a box, and a date placed above it for future reference. After
having performed an operation of this kind one afternoon in October
1858, I saw a Hermit-Crab (who had cast his shell on the previous
day) hurriedly leave his testaceous dwelling, then scrape away at his
tail, and after a moment's interval, leap into his old seat again. On
inspection, I found to my surprise _that he had actually_ _slipped off
the skin of his tail_![7] much in the same fashion as we would draw off
a well-fitting glove. Here was a strange and unexpected discovery.
[7] The fact of the exuvium of the Hermit-Crab being cast off in two
pieces, and at different periods, I have since confirmed 'many a time,
and oft.'
On submitting the exuvium to the microscope, we find that the covering
of the false feet, and the cilia attached to the same, all remained
fixed in their natural position to the tail-piece. Although in several
cases I have had no difficulty in discovering the rejected cuticle of
the tail, at other times it has eluded my search. The cause of this
I cannot explain. It may be that the animal, adopting the habits of
the toad, swallows a portion of its exuviæ as soon as cast. On two
occasions I found the slough of the body and claws of a crab, and
waited patiently for several days, without success, expecting to get
the tail portion. Growing impatient, it occurred to me that it would be
a curious experiment to try and draw off the exuvium with my fingers.
This was easy to talk about, but difficult to perform.
In the first place, the crab would not, if he could help it, allow
himself to be handled even in the most gentle manner. To overcome
this difficulty the shell had to be broken. This was done; but, alas!
the shock nearly killed the poor little Hermit. After some trouble,
I carefully unwound his body from the whirls of the Top Shell, and
proceeded to perform the intended operation. Reader, have you
ever seen a child take a rose-bud in his hands, and force open its
half-pouting blossom, in the belief that by so doing he was assisting
nature? If so, you must have watched the puzzled expression of the
boy's countenance when he beheld the leaves fall one by one at his
feet, and the bud itself exhibit evident signs of approaching decay.
In just such a position did I stand with regard to the poor
Hermit-Crab, for, in spite of all my care in manipulation, the skin
of the animal was so tender and delicate that the first gentle pinch
caused a puncture which proved fatal; and as to drawing off the
covering, the thing I now believe to be impossible, even under the most
favourable circumstances.
The upper portion of the Soldier-Crab, I may mention, is cast off in
one piece, while the animal is seated in its turbinated dwelling. The
act is performed with the most perfect ease. Unlike the _Brachyura_,
the _Anomoura_ do not exhibit signs of such rapid growth immediately
after exuviation, but increase in size very gradually indeed.
CHAPTER VII.
Prawns and Shrimps.
'Men holden ye therefore prophanes
Ye eaten neither shrimps nor pranes,'
VII.
Although abundant at many parts of the Scottish coast, at Cockburnspath
(situated near the mouth of the Frith of Forth) only, has the writer
met with the very beautiful prawn, _Palæmon Squilla_. At this locality
specimens were very frequent in rock-pools situated near the shore, nor
were such difficult to capture. The small net being placed cautiously
over their head, the animals did not show signs of resistance, until
they found themselves, by a sudden jerk of the hand, drawn bodily out
of the water. Then, indeed, unless some degree of skill was used, the
captives would give a powerful spring, and escape, from the confinement
of the net, to the more congenial element from which they had been so
unceremoniously ejected.
Prawns (_Palæmonidæ_) exuviate very frequently, in some instances as
often as once or twice a month. No sooner is one coat thrown off and
the Palæmon recovered from the weakness which the process occasions,
than it commences, at first at intervals, and then almost incessantly
day and night, preparations for a renewal of the wonderful operation.
Every part of the body--eyes, antennæ, and especially the sub-abdominal
fins, to certain portions of which the ova are attached in groups,
and the lobes of the tail--are submitted to a severe rubbing and
brushing process. The appearance of the prawn at this period is
really most interesting, and, I may also add, amusing. Sometimes the
tail is compressed inwards, beneath the body for a few seconds, and
then suddenly elevated and forced out with donkey-like extravagance
of gesture, the animal the while standing upon its first pair of
forcep-like feet.
At the appointed time the shell opens at the back part of the head,
and the prawn becomes gradually freed from its old covering. The
marvellous process completed, like all its crustaceous brethren, the
creature becomes to a certain extent helpless, and if such convenience
be afforded, retires for protection beneath some shell or fragment
of rock, from whence it soon re-appears, and repeats its gymnastic
exercises, which cease, however, for a few days, as soon as the new
coat is sufficiently hardened.
The prawn is an extremely interesting occupant of an aquarium, from
the fact of its being constantly on the move, and also on account
of the pretty blue and orange markings of its many-jointed legs,
and the singular transparent appearance of its body. This latter
feature is made still more notable when the animal happens to have the
ova attached, as the latter are opaque, and of a deep brown colour
approaching to black. By the prawn the act of exuviation seems to be
considered an event of no slight importance, and, although occurring
so frequently, is fraught with danger. Specimens oftener die at the
moulting time than at any other. In fact, unless I am very much
mistaken, they are then subject to some peculiar disease, which is
apt to prove fatal. At all events, several of my little captives,
after having performed their gymnastic movements (before alluded
to) for several days, turned sickly, and died. The commencement of
their illness was always denoted by a small, white, opaque dot that
mysteriously appeared in the centre of the body. This object speedily
increased in size, until it eventually spread over the entire animal.
Then, no longer diaphanous, the flesh of the prawn seemed composed of a
solid substance not unlike lime or pounded chalk.
The Shrimp is so common, and so well known, that a lengthened
description of it is unnecessary. I shall, therefore, merely record
an ingenious plan by which specimens of the _Crangon vulgaris_ may be
procured by visitors at the sea-side, who do not care to wade in the
water with a large net.
It is one generally pursued by Scotch boys as a mere amusement, for
neither shrimps nor prawns are eaten to any great extent by the
inhabitants of Scotland generally.
On arriving at a pool, a person will soon know whether shrimps are
contained therein, from the number of sand clouds that are raised by
these little crusty fellows at any intrusion upon their privacy. Many
persons employ a hand net, and pass it rapidly through the water,
thinking thereby to startle and entrap the animals in question.
Sometimes the plan succeeds, but more often it turns out a failure.
Instead of using the net, let the young zoologist stoop down, place the
palms of his hands suddenly upon the surface of the sand, then slowly
draw them near each other, at same time cautiously close the fingers,
and he will in all probability feel the objects of his search wriggling
to escape from his unwelcome and unfriendly grasp.
To satisfy curiosity, take one of the captured specimens and drop it in
the sand that surrounds the cavity in which your skill as a shrimper
has been exercised, and I will venture to assert that, in an instant,
the little creature will have disappeared as if by magic--such is
the wonderful rapidity with which the shrimp burrows itself. Even
when lying upon the surface a practised eye is required to detect the
presence of a shrimp, in consequence of its colour being of the exact
shade of the sand in which it hides. In clear pools its body is of
a light drab colour, which becomes changed to a dark tint when the
animal is located in a pool, the base of which is of a sombre hue.
The prawn, or shrimp, is somewhat of a gourmand, and requires to be fed
occasionally. The most simple food to give either, when in an aquarium,
is an open mussel or cockle. A marine worm, such for instance as the
_Terrebella_, however (as on one occasion I vexatiously discovered), is
a dainty more highly prized than the flesh of a bivalve, but one which
cannot often be indulged in from its comparative rarity.
CHAPTER VIII.
Acorn Barnacles.--Ship Barnacles.
'Barnacles turn Solan Geese
In the islands of the Orcades.'
VIII.
If the reader has been struck at what has been said in regard to the
exuviation of crabs, &c., he will probably be more surprised when I
state that precisely the same phenomena take place in the simple _Acorn
Barnacle_, that studs in countless numbers almost every rock and shell
situated between tide marks. No one can visit the sea-shore, at certain
localities, without noticing the white spots which constitute the
shells of the cirripeds in question, although he may not be acquainted
with the marvellous beauty of the animal contained within each.
Its loveliness, it is true, is in no wise apparent when parched and
dry; but let the welcome waves advance and playfully dash their spray
against the dwelling of the little crustacean, and quickly its valves
will open, displaying a delicate feathery plume, thrust forth and
hastily withdrawn again.
As it is not convenient to watch the movements of this animal in a
rock-pool, let me request the reader kindly to take a peep into my
aquarium. Here is a Trochus shell, for example, inhabited, as you
perceive, by a Soldier-Crab, the surface of which is thickly covered
with shelly cones, of small dimensions. These are the Barnacles
(_Balani_). The Trochus most fortunately being near the side of the
glass, is capitally situated for our purpose. Take the hand lens,
adjust its focus, and watch carefully for the opening of the cones.
Tush! The hermit never _will_ rest contented in any position for two
consecutive minutes; but see! as he walks away the fairy hands are
being rapidly thrown out and made to sweep the water in graceful
curves, thereby suggesting some resemblance to a bevy of school
children at Christmas time, bidding _adieux_ to their friends, while
seated on the roof of an old stage coach.
Carefully I lift the Pagurus bodily out of the tank, and transfer him
to a wine glass filled with clean water. After a few minutes have
elapsed, the hands again commence their fishing operations. Observe,
now, that these organs fan the fluid in such a manner as to catch any
animalculæ that may be near, and draw them towards the aperture caused
by the opening of the valves of the Barnacle. A close inspection will,
I am sure, prove to your satisfaction that there is also distinctly
apparent a second and smaller cluster of feathery fingers, whose duty
it is to catch the food, brought near by the larger and corresponding
organs, and finally convey it into the mouth of the little cirriped.
There may be, in the wide range of Nature's lower scale of life,
prettier sights to gladden the eye of the student than that above
described,--but if so, I must confess _my_ inability to indicate where
such are to be found. The fishing apparatus here mentioned consists of
a number of slender _cirri_, thickly coated with microscopic filaments
(cilia), and is, at certain periods, thrown off complete and entire by
the process of exuviation, just as we have seen it occur in the higher
crustacea.
Would you, my young friend, like to procure an exuvium of the Barnacle
for examination? Yes. Then follow the directions I am now about to
give, and your wish will be speedily gratified.
Presuming that your tank already contains a number of Barnacles
attached to various objects, and that such have been in the same vessel
for some weeks; syringe the water for a few minutes, and you will
find floating about, or rising to the surface, many specimens of the
desired object. They will, in all probability, be visible to the naked
eye. To attempt to lift one out of the water, however, by means of
your finger and thumb would be utterly useless. Such a procedure, even
were it successful, would inevitably mar the delicate beauty of this
'inessential' object, which, spirit like, casts no shadow upon weed or
water. The best plan is to insert a tube of glass into the aquarium, in
such a way that the exuvium may ascend the interior. Then place your
finger on the top, and draw the tube out of the water, and you will be
able to deposit the skin of the Barnacle upon a slip of glass by merely
lifting off your finger. The specimen can then be leisurely arranged,
and spread out by aid of a hand lens and fine pointed needles.
Walking by the sea-shore one fine summer afternoon, I met a fisher
boy running along with some curious objects spread out in the palm of
his left hand, while in his right, suspended from finger and thumb,
appeared a still more desirable prize.
At first glance I detected the objects to be specimens of the _Lepas
anatifera_. They had, so the boy stated in answer to my inquiries, been
plucked from the base of a ship newly arrived from a long voyage. When
I offered him sixpence for the 'lot,' the embryo plougher of the deep
looked up in my face with a singularly mistrustful expression, and
said, 'D'ye mean it, sir?' I gave speedy assurance of my sincerity,
and on receiving the purchase money, after handing over the Barnacles
to my custody, the young urchin started off as fast as his legs,
encased in huge wading boots, would allow him. His alarm was quite
unnecessary, for although in a few days after I would not have given a
penny for a thousand, I would willingly, on the above occasion, have
paid five shillings for a single specimen, rather than have missed
the opportunity of possessing such an interesting object as the Ship
Barnacle.
On placing them in water one only of the creatures showed any signs
of life, and by next morning they made the scentral organ of my face
so highly indignant that, in order to allay its irritability, I was
obliged to remove the defunct animals to the outside of the window.
There they remained for several months, and were eventually transferred
to the privacy of a card-board box. Although twelve months have elapsed
since the last-mentioned removal took place, these creatures even now,
when the lid of the case is lifted, give out a smell, so 'antient and
fish-like,' that I believe not a few of 'the sweet perfumes of Arabia'
would be needed in order to subdue its power.
One cluster contained thirty Lepades, and the other eighteen. The
average length of each Barnacle is about three or four inches.
One, however, measured nearly ten inches. The fleshy stalk is of a
purplish-grey colour, semi-transparent, and perfectly smooth. The
shell, which consists of five pieces, is bluish-white, while that
portion from whence the cirri protrude appears of a brilliant orange,
the cirri themselves being exquisitely tinted with violet, shaded off
to a deep purple.
I may here mention that the above animal was by our ancestors most
unaccountably supposed to be the young of the solan goose!--a bird that
haunts in vast numbers the Bass Rock and Ailsa Craig. Indeed, a common
belief in different parts of Scotland, and over the west of England
was, that the shells grew upon certain trees, and in process of time
opened of themselves; whereupon a certain animated substance contained
within the shell dropped down, and according to the place where it fell
perished or fructified. By falling into the water it grew to be a fowl;
but by falling upon land the vital principle became extinct. The fowls
which resulted from the more fortunate contingency were called Barnacle
Geese in Scotland, and Brant, or Tree Geese in England. This delusion
appears to have arisen from the fact of Barnacles having been found in
great abundance on trunks and even branches of trees long submerged
in the sea.[8] Bishop Hall thus alludes to the popular notion in his
Satires:--
'His father dead! tush, no, it was not he;
He finds records of his great pedigree;
And tells how first his famous ancestor
Did come in long since with the Conqueror.
Nor hath some bribed herald first assigned
His quartered arms, and crest of gentle kind;
_The Scottish Barnacle, if I might choose,
That of a worme, doth waxe a winged goose_.'
[8] Vide author's 'Seaside and Aquarium.'
CHAPTER IX.
Phyllodoce Laminosa--the Laminated Nereis
'His meaner works
Are yet his care, and have and interest all--
All, in the universal Father's love.'
--COWPER.
[Illustration:
1 COMMON BARNACLES attached to shell of Limpet
2 ANIMAL OF THE LIMPET (_P. vulgata_) as seen from below
3 THE LAMINATED NEREIS (_Phyllodoce Laminosa_)]
IX.
To oblige an English correspondent who requested some blocks of
stone containing Pholas perforations, the writer, in company with a
fellow-student, started betimes for the sea-shore, some four miles'
distance. We made for a certain spot, where it was expected the object
of our wishes could easily be found. Our equipment consisted merely
of a hammer, a bottle, and two chisels, enclosed in a carpet-bag, the
better to mask our mission from impertinent curiosity.
On reaching the shore, it soon became painfully apparent that no pieces
of rock could be procured of a character at all suitable for a museum.
To make matters still more irritating, a breeze arose, and with it
came a furious shower of rain, which soon completely saturated our
light costume. At such a time it is laughable to note how faint becomes
the poetry of practical zoology--how excessively like street puddles
are the fairy-grots, as the rock-pools are called; how unsightly the
great, distorted anemones look, too, when viewed from beneath a large
boulder, where you are crouched in the fond idea that you are thus
getting shelter from the rain.
On this occasion, my friend and I, being soaked to the skin, started
up from our unpleasant position, and boldly daring the rain to do its
worst, proceeded to hunt after any object of interest that might by
chance be lying stranded near.
After an hour's search, two objects, among many others of more or less
interest, were captured, that fully repaid us for our uncomfortable
'ducking.' The first was an elegant Actinia (_A. Dianthus_), which
seemed to be exquisitely modelled in the finest virgin wax. The second
was a specimen of the Laminated Nereis (_Phyllodoce Laminosa_), a
wonderfully beautiful _worm_!
Fair reader, start not nor curl that rosy lip of thine at the
expression, 'beautiful,' being applied to such an humble creature, for
indeed the title is a just and true one.
This Annelid is generally found coiled up and attached to the under
part of stones situated near low water mark. Its general colour is
emerald green, excepting along the centre of the back, which is
iridescent, and reflects a brilliant blue, changing into purple and
other hues, only equalled in beauty by the enamelled corslet of the
brightest beetle, or the flashing tints that dance upon the plumage of
the humming-bird.
The body of the _P. Laminosa_, like that of all other _Dorsibranchiate
Annelidans_, is divided into a consecutive series of rings. Upon either
side of each ring is situated a singular appendage, which acts as a
gill or branchial organ, by the exercise of which the blood of the
animal is effectually purified, and respiration adequately provided for.
When the Nereis is in a state of repose, these gills are laid flat over
its back; but in a state of activity they are fully spread out, and act
as 'paddles,' by aid of which the animal is enabled to glide through
its native element with a graceful serpentine motion.
At the base of each paddle is situated a smaller one, consisting of
a fleshy pedicle shielding a fan-like bunch of hairs, each of which
tapers to a sharp point. Combined, these hairs or spines form a
powerful defensive weapon, which can be extended or retracted at will;
and it also serves as an _oar_, or propeller.
As a noteworthy instance of tenacity of life in the lower animals, it
may be well to mention here that I have on various occasions, by aid of
the microscope, watched for several minutes the bunch of spines, above
alluded to, thrust out and retracted in a single segment cut from the
body of the Nereis; and only as the object became devoid of moisture
did its beautiful mechanism cease to play.
The specimen now before me is comparatively small, being only twelve
inches in length, yet its body contains nearly one thousand lateral
appendages, constituting, it must be admitted, a most extensive and
wonderful locomotive apparatus.
This Annelid is not a suitable object for the aquarium, on account of
its frequent great length, and the consequent likelihood of its getting
entangled among stones and rock-work when in search of food.
If the hinder parts be cut off, as has been already hinted, they will
exhibit vitality for a considerable period when placed in water, but
we are told it is the anterior (?) portion of the Phyllodoce which
alone possesses the power of regenerating lost segments; these will be
reproduced sometimes at the rate of three or four in a week.
'These creatures,' says a learned author, 'as might be expected from
their activity and erratic habits, are carnivorous; and innocent and
beautiful as they look, they are furnished with weapons of destruction
of a unique and most curious description. The mouth of the Nereis would
seem at first to be a simple opening, quite destitute of teeth; but on
further examination, this aperture is found to lead into a capacious
bag, the walls of which are provided with sharp, horny plates, even
more terrible than those which are occasionally to be met with in
the gizzards of some of the higher animals. It is not surprising,
therefore, that by many anatomists the structure in question has been
described as a real gizzard, or by some as the stomach itself. A little
attention to the habits of the living Annelid will, however, soon
reveal the true character of the organ. No sooner does the creature
wish to seize its food than this so-called gizzard is at once turned
inside out, in which condition it protrudes from the mouth like a great
proboscis, and the teeth, which were before concealed in the interior
of the cavity, now become external, and display as formidable an
assortment of rasps, files, knives, saws, hooks, or crooked fangs, as
any one could wish to see. Let us suppose them, when in this condition,
plunged into the body of some poor helpless victim, while at the same
moment the proboscis is rapidly inverted and withdrawn; the prey thus
seized is at the same instant swallowed, and at once plunged into a
gulf where all struggles are unavailing, there to be bruised, and
crushed, and sucked at leisure.'
There is a curious fact in connection with these Annelids which is
too interesting to be omitted here. I allude to the wonderful manner
in which their young are produced by a process that may be called
'sprouting.'
This invariably takes place in the segment immediately preceding
the terminal one. When a new animal is about to be formed, the
reproductive segment swells, and after a certain time the infant
worm is seen growing from the tail of its parent. When sufficiently
developed, the offspring detaches itself, and starts life on its own
account. Sometimes before the elder born Annelid is fully formed, the
mysterious segment produces a second offspring, and, according to
Professor Milne Edwards, as many as six young ones may be generated in
succession from the same posterior segment, all of which will for some
time continue attached to the parent worm.
CHAPTER X.
The Fan-Amphitrite.
X.
At the lowest ebb of spring-tide may often be seen protruding above
the surface of the beach an object that at a little distance might be
mistaken for the twig of a tree, or a decayed and blackened reed. A
close examination discloses it to be a smooth, tough tube, apparently
composed of dark leather or old gutta-percha, affixed at its lower
extremity to some rock or other solid substance.
The pretty Annelid occupying this dark cylinder is the Fan-Amphitrite
(_A. ventilabrum_). Unlike the Terrebella, this animal may really be
captured without much difficulty. The first time I made the experiment
it was successful. By carefully digging down with chisel, or digits,
to the base of the tube, which may be reached in the course of a
few minutes, the entire structure, with its living occupant, may be
transferred to your extemporaneous tank.
I have an Amphitrite in my aquarium at the present time displaying its
richly-tinted tentacula to the sun, which lights them up with unusual
beauty.
As the 'case' of this animal is flexible, and as its owner will only
thrive in an upright position, the reader will easily conceive that
to afford the Annelid suitable accommodation in the aquarium is not
a very easy task. What other naturalists do I cannot tell; but the
following is the plan I adopt for the creature's comfort and my own
gratification:--
Having procured a small cylinder of glass (or gutta-percha), close up
one end, and drop in the Amphitrite, taking care to first tie the lower
portion of its sheath with a piece of thread or silk. It is very pretty
to see the plume of the Annelid spreading completely over and covering
the extremity of the tube, giving the idea in the one instance that the
animal was mysteriously gifted with the power of exuding gutta-percha
instead of its usual mucus.
The Annelid may be made to recline against the sides of the vase, or be
propped up on any chosen spot by aid of a small cairn of pebbles, and
thus form a very curious feature in the aquarium.
To test a fact, relative to the power which the Amphitrite is said
to possess, in common with other tubiculous Annelids, of renewing
certain portions of its body after sustaining injury, I snipped off the
principal portions of its branchiæ, and found that, after the lapse of
a few months, my specimen renewed its mutilated organs.
CHAPTER XI.
The Common Mussel.
'Travelling is not good for us; we travel so seldom. How much more
dignified leisure _hath a Mussel glued to his impassable rocky limit
two inches square_! He hears the tide roll over him, backwards and
forwards, twice a day (as the Salisbury coach goes and returns in eight
and forty hours), but knows better than to take an outside place on
the top on't. _He is the owl of the sea, Minerva's fish_, the _fish of
wisdom_.'
C. LAMB to B. BARTON.
[Illustration:
1 COMMON MUSSEL (_Mytilus edulis_)
a The foot
b The byssus
c c Muscles which regulate the action of the foot
2 THE MUSSEL CLOSED
3 THE BERÖE (_Cydippe pileus_)
4 THE FAN AMPHITRITE (_A. ventilabrum_)]
XI.
In his celebrated journey to the western islands of Scotland, Dr.
Johnson tells us that when at Ulinish, hearing of a cavern by the
sea-side remarkable for powerful reverberations of sound, he determined
to pay a visit to the spot. After dinner, having procured the services
of some boatmen, the doctor, in company with Bozzy, started off on
his trip, which, on the whole, appears to have been a pleasant one.
There was, however, no _echo_ to be heard; but to make up for this
disappointment, Mr. Boswell went angling, and caught a wee 'cuddy,'
(a fish about the size of a gudgeon), while the doctor was gratified
by the sight of some sea-weed growing upon stones, and above all, at
witnessing for the first time _Mussels in their natural state_.
The impression made by this candid acknowledgment upon our minds
is one of wonder, that a man like Johnson could have reached his
advanced years without having seen so common a sight. But it is
possible that even in our day, with its unprecedented facilities
for cheap travelling for the most inland inhabitants, there may be
many persons to whom the sight of a Mussel fixed to a boulder by its
self-constructed cable, would be as great a novelty as it was to the
eloquent author of Rasselas.
It is, however, one of the commonest appearances which meet the eye of
those in the habit of visiting the sea-shore. At certain localities
myriads of Mussels may be noticed attached to the surface of the rocks.
So thickly are these sometimes covered over, that the blade of a knife
cannot be inserted at any part without touching one or more of the
esculent bivalves that are to form the subject of this chapter.
The Mussel anchors itself by means of the Byssus; or, as it is commonly
termed, the 'beard.' This appendage is composed of various slender
threads which are attached to any object within reach, whether such be
the shell of a neighbouring Mussel, a small stone, or huge boulder.
The members of each colony are thereby bound together, it may be
figuratively said, by the silken cords of friendship, and mayhap of
love. The _Mytili_ evidently believe that 'there's no place like home.'
Although gifted with a power of moving about at will, they never
attempt to exercise this when living together in a family circle,
but pass through life's stages upon the spot where they were born.
Certainly, if there be such a sight as a truly happy and contented
family in the marine animal kingdom, it is to be found exemplified in
these bearded molluscs.
As hinted, they live shoulder to shoulder, back to back, and otherwise
mutually support each other. They need not look about for a single
meal, but have merely to allow themselves to be fed by the waves, which
yield them a constant supply of fresh and wholesome food. Their sole
duty in this respect is limited to the selection of objects suitable
to their palate. Their 'at homes' being so frequent, the _Mytili_ can
boast of a large circle of acquaintances. The Periwinkle, and his
friend Silver Willie, often make a morning call, take pot luck, as it
is termed, and then politely retire. _Mr. Carcinus Mænas_ and his poor
and dirty relation, _Maia Squinado_, perchance look in of an evening.
_Solaster Papposa_, or occasionally the lanky-legged _Uraster Rubens_,
and other 'stars' of the marine world, crawl in at unseasonable hours
in their usual lazy style, and are generally rewarded by finding the
doors (valves) shut against them. This 'cut direct' does not appear to
be at all annoying; or if so, the Star-fishes are too cunning to show
it, for they quietly saunter away as if they never had the slightest
wish to put their feet within their neighbour's dwelling.
There is a 'black sheep,' as Sir Pertinax Mac Sycophant would say, who
intrudes himself into Mussel society, and plays sad havoc among its
members. This crawling rascal is the wolf of all Musseldom flocks.
Young and old alike experience the blighting effects of his villanous
propensities. The name of this obnoxious personage is _Purpura
Lapillus_ (Common Whelk). What, the reader will ask in surprise, a
univalve prey upon a bivalve? Is that possible? It is, unfortunately,
too true.
If we take a Mussel in our hand we shall find it perfectly impossible
to force its valves asunder, without the aid of a strong knife or other
instrument; yet the Common Whelk, fleshy and insignificant creature
though it be, will consume the animal within, and make the valves
fly open in a brief space of time, by means of its soft tongue. But
leaving such general remarks, let us suppose we are standing before a
boulder covered with these mussels. Numbers of gaping shells may be at
intervals perceived still attached to the rock, but with the interior
of each valve so empty and smooth, that we could scarce believe they
had ever embraced a living occupant. On taking up one of the valves and
closely examining it, do you observe nothing peculiar about it now?
'No.' Take up the other then, and submit it to a similar inspection.
Well, what do you see now? 'Nothing,' you still reply, 'unless it be a
peculiar little hole about the size of a pin's head, which surely is
of no importance.' That little hole was of _vital_ importance to the
poor mollusc, for through that aperture the life and substance of the
Mytilus was drawn by the voracious Purpura.
But the poor Mussel is exposed to the attacks of other enemies--aquatic
birds, as sea-gulls and ducks, eagles, vultures. Even water-rats and
monkeys may also be included in the list.
It is amusing to see a gull, by no means a foolish bird, standing
patiently before a Limpet, for example. The animal, unsuspicious of the
presence of an enemy, raises his canopy with the view of relaxing his
overstrained muscles, and is instantly toppled over by the intruding
beak of the bird. If unsuccessful in his first attempt, the gull is
well aware it would be useless to try a second time at that tide.
But if a Mussel be the object of attack, it is wrenched from its seat,
raised to a certain height, and then allowed to drop upon a stone with
the view of breaking the shell. In one locality called Mussel Bay, Mr.
Barrow says he disturbed some thousands of birds, and found so many
thousands of shell-fish scattered over the surface of a heap of shells,
that, for aught he knew, would have filled as many thousand waggons.
This habit of the feathered tribe was, by the way, well known to the
ancients, and I may be pardoned relieving my pages by a quotation on
the subject from the 'Shepherd's Calender' of Spenser, whose exquisite
descriptions of natural history are as marvellous as his allegorical
poem. The author of the 'Fairy Queen' thus humorously reads a lesson
to an ambitious man,--
"He is a shepherd in gree,
But hath been long ypent,
One day he sat upon a hill,
As now thou wouldst mee;
But I am taught by Algrinds ill,
To love the lowe degree.
For sitting so, with barred scalpe,
An eagle soared hye,
_That weening his white head was chalke,
A shell-fish down let flye!
She weened the shell-fish to have broke,
But therewith bruised his brayne_,
So now astoined with the stroke,
Hee lyes in lingering payne!"
It seems remarkable that the 'illustrious French naturalist,' Reaumur,
should have been the first, if not to discover, at least to publish,
any description of the manner in which the Mussel spins its silken
cable. Yet one hour's experience in a tea-cup or tumbler will exhibit
most of the features in this interesting process.
That Reaumur's narrative, although usually copied by most writers of
the present day, is not strictly correct, and, moreover, that the foot
of the mussel is _not_ 'useless as an instrument of progression' (as
generally asserted), may be easily proved to the satisfaction of the
student by adopting some such simple experiment as that which I am now
about to describe:--
Being at the sea-side on a fine summer afternoon, I procured three
specimens (I might have had as many hundreds if disposed) of the
Mytilus. On my return home I placed them in a common tumbler, and
waited patiently to see the result. My object was, if possible, to
witness the manner in which this animal grows its beard.
In less than five minutes an industrious little fellow, whom we will
call No. 1, gently opened his shell, and immediately protruded his
fleshy foot until it reached a length of nearly two inches. So far as I
could determine, the design of the Mussel was to discover, in the first
place, what kind of a lodging he occupied; whether or not he had any
companions; and also, to know if these or any other objects could be
found worthy of his _attachment_.
Sometimes the foot would be protruded under the shell, then in a
contrary direction. Or by an exertion of the strong muscular power
which that organ possesses, the entire shell would be lifted off the
ground and urged forward to a considerable distance. Of course he soon
come in contact with a neighbour Mussel, whom we may term No. 2, but as
the latter was not anchored by any byssus, he was speedily pushed on,
and on, until No. 3 was met, and the latter, in his turn, made to take
up a new position.
Being tired of wandering about, No. 1 then extended his foot along the
base of the vase to a certain point, and there let it rest for a few
seconds. When again withdrawn, to my great delight, I saw the first
thread of a new byssus had been constructed.
As my principal object was to become acquainted with the mode of
formation of the beard, I did not feel satisfied with merely watching
the movements of the animal from above. After a brief interval another
thread was spun. I bore in mind the words of Reaumur, who says, 'The
Mussel never spins more than four or five threads in the twenty-four
hours.' Aware that no time must be lost, though still afraid to disturb
the mollusc lest it might suspend its labours, I instantly detached
my specimen, and again turned its shell round so as to bring the
opening of the valves against the face of the glass. The creature did
not seem at all offended at his handiwork having been destroyed, but
still obstinately refused to let me see the working of its foot. Again
was the shell rolled over, and again did I replace it in its former
position. This time, in order to keep it from being shifted, a stone
was deposited upon the valve. Nothing daunted, the animal gradually
separated the valves of its shell, and at the same time advanced and
elevated its foot to the exact position that I had so long desired.
The spinner, when at its full length, was pressed firmly upon the
flat surface of the glass, and there allowed to remain for a while.
Suddenly, at nearly _half an inch distance from its extreme end_ (or
point), a little mouth was seen to form, about the size of a large
pin's head, from which there issued a milk-white fluid, that gradually
hardened and became fixed to the glass. This object being light in
colour, had a pretty effect when contrasted with the rich brown tint
of the spinner. Shortly afterwards the foot rolled over and withdrew
into the shell, leaving behind it the silken thread which had just been
spun. The 'little mouth,' above described, was, if I may so term it,
the mould in which the end of the thread was cast.
In the course of two hours a bundle of byssus threads, sixteen in
number, were produced by this industrious little labourer.
Having thus seen that the foot is useful to the Mussel as an instrument
of progression _before_ the beard is formed, let me now endeavour
to show that it is, at times, of equal service for the same object,
_after_, and when the mollusc is anchored thereby to any particular
spot.
When we remember that this anchorage is formed of a harp-like set of
strings, amounting to ten or even _a hundred_ in number, it does seem
an almost incredible fact that the Mytilus is enabled to change its
station, even when living in single blessedness.
To see a Mussel 'flit,' is a sight one may often watch and wait
for without success. On the other hand, when least expected, the
self-willed mollusc may commence operations. When about to take up
a new home, the animal shaves off its beard entirely, or in more
scientific language, 'rejects its byssus' altogether. In order to
excite the locomotive instincts of my specimens, I used to cut all
the threads of their cable except one. The animal being suspended, of
course its whole weight was then thrown upon a single fibre. Such a
state of insecurity was by no means agreeable, and I generally found in
the course of a few hours that fresh threads were rapidly thrown out,
and an entirely new byssus formed; the old one, which was broken off at
the root, being left behind as useless.
Another singular peculiarity of the Mussel which came under my
observation has not been, so far as I am aware, noticed by previous
naturalists. I allude to the power which the animal possesses of
lengthening out the root or stem of the beard, apparently to an
unlimited extent. This power appears to be seldom exercised, for
although I have had hundreds of specimens of the Mytili, in only one
instance have I witnessed the phenomenon in question.
A large specimen of this bivalve, procured accidentally from a fishwife
in the street, was dropped into the aquarium, and placed close against
the surface of the glass. The animal seemed highly delighted with its
change of situation, for in a few moments the valves were opened, and
a long draught of water taken in to bathe its branchiæ, and furnish
a hearty meal. Having satisfied its appetite, the next process, of
course, was to find out what kind of a home he had been introduced
into. The foot, a noble specimen, was soon protruded, and one after
the other, in rapid succession, various threads were formed. By next
morning the animal, advancing by a series of easy stages, had reached
the surface of the water, which was exactly five inches deep. I knew
it would not remain long in this position, and was anxious to discover
what plan would next be adopted. Several courses were open to him.
For instance, like a marine Captain Cook, he might circumnavigate his
little _Globe_,--or he might let go his cable and drop plump to the
bottom,--or he could follow the route I had often seen taken by his
relations, viz., to journey back to the place from whence he started.
It pleased him, however, to strike out into a new path,--to devise a
method of his own. While located near the top of the tank, he threw out
exactly ninety-eight threads, not certainly for security, but merely,
it would appear, for pleasure.
Then slowly but surely, day by day, he lengthened out the stem of his
byssus tree, until it reached the extreme length of nearly five inches.
To what further degree it would have been extended, had the mollusc not
reached the base of the tank, it is impossible to conjecture.
No sooner did the shell touch terra firma, than the cable which had
taken so long to spin was immediately broken off. I have succeeded in
keeping the same animal by me for the last twelve months, but have seen
no attempt at a renewal of the operation, in the progress of which I
had taken so lively an interest. I may add that this Mussel taught me
another lesson; it was this: in my early studies regarding the habits
of the Mytilus, I had adopted a certain theory of the manner in which
the beard was formed; and having watched so long, and witnessed the
process so repeatedly, I thought myself justified in forming certain
conclusions. My belief was that the creature could not form more than
one thread at a time, _without withdrawing its foot into the shell_, as
I believed, in order to procure a fresh supply of material. That this
notion was erroneous, this animal proved to my entire satisfaction. Not
only may one, but two, three, four, and even six threads be attached
to any selected object, the point of the foot being passed from one
position to another, without the organ being withdrawn into the valves
until the whole of the threads are formed. How many more the Mussel is
capable of producing at one 'stretch,' I have no means of knowing, but
six is the largest number that any of my specimens in such case have
ever fabricated.
The general idea seems to be that the Mussel works in the same manner
as the spider, who emits a drop of liquid against some foreign
substance, which, being allowed to harden somewhat, is then drawn out
as the spider recedes. This notion, I may state, is quite erroneous.
When the sucker of which we have spoken is formed, _the thread is
completed_. It is true that the foot as it retires into the shell
generally glides down the newly-constructed filament, but this is not
of necessity, nor does such circumstance invariably occur. Indeed,
while busily engaged in attaching a disc to the glass, the muscles of
the foot will contract, and thus throw open the folds of the groove,
situated in the middle of that organ; when thus exposed, the byssus
thread may be seen in the furrow, stretched like the string of a harp
or dulcimer.
While the end of the thread is being attached to a certain spot, a
conspicuous muscular action is perceived going on in the foot, which
alternately swells and contracts, as if something were being pumped
up through the byssal channel, until it reached a certain point.
There being dilated and spread out in successive layers, it assumes a
trumpet-like disc, which is firmly fixed to the foreign object. Indeed,
I am by no means certain that the thread is not, when first produced,
exactly like a trumpet in shape. It also conveys the idea of being
blown out in a similar manner to a piece of bottle glass. After being
exposed to the air for some little time, the hollowness of the thread
is not so apparent as when it is newly fabricated.
The mucous fluid, from which the fibres are formed, is secreted in
a gland situated at the base of the foot, whence it is apparently
expelled at the will of the animal into the furrow already referred
to, and is there spun into threads. The toughness of these filaments,
considering that each is finer than the thinnest strand of silk, is
remarkable. Their strength, however, may be easily accounted for,
when we know that each is composed in reality of innumerable delicate
threads, bound together by a subtle gelatinous fluid. This phenomenon
may be made out quite distinctly with a common hand lens, if the
following simple experiment be adopted: Make a Mussel construct its
thread in such a way that the disc of each is planted on the face of
the glass. Then place the fine point of a common needle upon the outer
edge of a chosen disc or sucker, and gently draw the former away to
a little distance, and you will find that by so doing the stretched
string becomes _peeled_. Continue this process carefully, and before
the thread gives way you will have divided it into a dozen parts at
least, all of which are visible to the naked eye, but clearer when the
hand lens is used, and still more distinctly and beautifully defined,
of course, if the microscope be brought into play.
The foot of the Mussel appears to be firmly strapped on, as it were,
to certain transverse muscles, by a contraction of which the animal
closes its shell with surprising force. This strap, composed of a
powerful tendon which passes under the adductor muscles, is attached at
either end to the base of the foot. Thus we account for the remarkable
strength which is evidently seated in the foot, and makes it of so much
importance to the animal. At first sight nothing appears more easy
than to pluck out this organ by the roots, but an attempt will prove
the experiment to be more difficult than many persons suppose.
The colour of the foot varies considerably in different specimens,
even of the same species. Some, for instance, are of a chestnut brown;
others of a kind of mauve or purple, covered with a peach-like bloom
during life; others, again, are of a deep-toned umber, while not a few
are pearly white, and streaked sometimes with pink like a tulip.
The peculiarity of the Mussel to attach itself to foreign substances
has been taken advantage of for the benefit of man, and a curious
instance is exhibited at Bideford in Devonshire, at which town there is
a bridge of twenty-four arches, stretching across the Torridge river
near its junction with the Taw. 'At this bridge the tide flows so
rapidly that it cannot be kept in repair by mortar. The corporation,
therefore, keep boats in employ to bring mussels to it, and the
interstices of the bridge are filled by hand with these mussels. It is
supported from being driven away entirely by the strong threads these
mussels fix to the stonework.'
Like most other writers who quote this strange account, I have not
had ocular proof of its accuracy.[9] That it is quite probable I can
readily believe, as a pretty experiment will partly prove it to any
spirited aquarian. Following out the above idea of the bridge at
Bideford, I managed to build an exceedingly pretty centre piece for my
tank.
[9] Since writing the above, I have received the following interesting
epistle from Mr. Edward Capern, the celebrated 'poet and rural postman'
of Bideford, who kindly sought out the information I desired, relative
to the present state of the bridge above alluded to:--
Bideford, January 27, 1859.
DEAR SIR,--I have inquired of the bridge warder, and he informs me that
the feoffees of the bridge command mussels to be brought up by the
cart-load, to protect the foundation, which is laid on _rubble_.
I am pleased that it has been in my power to procure this information
for you--I am, dear sir, faithfully yours,
EDWARD CAPERN.
Having no ready means of making a rock arch, I collected such pieces
of rock, stones, &c., with weeds attached, as I thought would answer
my purpose, and then proceeded to fabricate the object of my wishes in
the following simple way: First were laid two stones parallel to each
other at three or four inches apart. Upon these I placed a large piece
of rock in a transverse direction. Between the interstices a number
of small mussels were then inserted. When fully satisfied that the
bivalves had moored themselves, I gradually piled one piece of rock
upon another until the structure reached the desired height, each piece
being bound to its neighbour by means of the byssus threads of the
Mytili.
Before each block of stone that formed the foundations of the arch
was placed a splendid frond of Lettuce Ulva, tied by a strand of
silk to a white pebble. These verdant fronds, so smooth in texture
and so gracefully convoluted, rising up from the base of the tank
and reaching to its brim,--mingling, too, with the various tufts of
corallines and other sea-weeds that jutted from each crevice, were
very pretty to look at. When disturbed by the movements of the fishes
passing in and out, the gracefulness and beauty of the sea-weed was
doubly increased.
In making observations upon any bivalve, such as the Mussel, it is
extremely puzzling to know what is going on _inside_ the shell.
Yet it is almost necessary to acquire this knowledge by means not
always apparent, in order to satisfy one's mind relative to certain
appearances, which we perceive going on externally. We have to form our
judgment of things we do not see from those that are apparent--at all
times a difficult task. But not often so tantalizing as in the case of
an insignificant creature like the Mussel, who lives, moves, and works
constantly before our eyes. I may add that it was not enough for me
that I saw the spinning process frequently. It all seemed tolerably
clear to my mind, but still I did not feel thoroughly satisfied. My
desire was to peep into the shell, and find out where the last spun
thread was situated; or, in other words, from what part of the trunk
the new branch sprung. On examining various specimens of the byssus,
this point was by no means apparent. Various means I adopted failed
to secure me the requisite knowledge. At length I hit upon a plan,
which, after no long time, I found opportunity to put in practice. My
largest Mussel lifted up its testaceous canopy, put aside the fringed
and fleshy veil that surrounded its edge, protruded its spinner to
make sure the ground was secure, and then withdrew it again into the
shell as usual. After the lapse of a second, the foot reappeared and
was stretched out to an unusual length. No sooner was the end of the
thread formed on the glass than immediately I firmly pressed the valves
together, and held them in this position until I had gradually worked
the Mussel up out of the vase, when I bound them close together by
means of a piece of cord. I need not describe my manœuvres further;
suffice it to say that the thread nearest to the base of the groove
was found to be the one that was spun last. This, in my opinion, is
invariably the case.
I may mention that the above experiment also proved to my mind that the
foot must be a most important vital organ of the Mytilus. At times, on
placing an open Mussel in my tank as food for crabs or other animals, I
have noted that if every other part were eaten, and the foot allowed to
remain attached to the muscles of the bivalve, that member would after
a lapse of several days show signs of--I do not say life--but sensation
and retractile power.
But when the foot is cut and otherwise injured, the animal dies
quickly. In the experiment mentioned the valves were not kept closed
for more than half an hour; yet when they were opened, vitality had
evidently ceased within. This was the more singular when we remember
that the Mytili will live for many days out of the water; the shells,
of course, during the whole period being firmly closed.
The Mussel, as already hinted, is very tenacious of life. I have kept
specimens by accident for several days in the pocket of my coat, but
found them quite well and lively when placed in sea-water.
In general the sure sign of their not being in a healthy condition is
when the shell opens; for, while the animal retains any sense whatever,
it exercises a strict and judicious 'closeness.'
I have found, however, on several occasions, that the shell being
contracted is not always a valid proof of its owner's convalescence,
for when placed in water the Mussel would float for several days upon
the surface like a cork, although it was near death's door.
This phenomenon must be caused, I should suppose, by some sudden fright
compelling the mollusc to close its shell with such rapidity as to
prevent a proper supply of water being taken in. Having only air to
exist upon, the animal then lingers on until its branchiæ become dried
up, and all moisture exhausted. In this state the Mussel opens its
shell with a deep bursting sigh, and sinks to the bottom--dead.
Being at the sea-side one fine summer day, I heard a little Scotch
girl cry out to her brother who was about to swallow entire, a fine
specimen of the _Mytilus edulis_, 'Eh, Willie dear, dinna ye eat that.
Dinna eat the _beard_ or ye'll dee!' Many years ago I remember a remark
to the same purport as the above being made by a poor child to its
playmate, in the neighbourhood of Gravesend.
I little thought at that time that the Mussel was so interesting a
shell-fish, or that I years after should spend many an anxious hour
studying the formation and nature of its despised beard.
I need hardly state that the idea of the beard being poisonous is a
vulgar error. In general the fish may be eaten entire with impunity.
Cases have occurred where persons have been taken ill after eating it,
but this result has been satisfactorily explained to have been caused
by the Mussels being procured from places such as Leith Docks, where
their food consisted chiefly of unwholesome and putrescent matters.
This mollusc is not used as food to any very great extent by the poorer
classes. It is employed very extensively, however, by the fishermen as
bait along all parts of the British coast. But in France it is much
esteemed both by rich and poor. The trade in them is successfully
cultivated, and affords a means of support to hundreds of industrious
and deserving men.
From the learned author of the "Rambles of a Naturalist" we learn
that at the village of Esnandes, on the coast of France, the Mussel
trade, commenced about eight hundred years ago, has assumed a gigantic
extent. Both here and at the neighbouring villages of Charron,
Marsilly, Mussels are bred in an ingenious and systematic manner. At
the level of the lowest tide short piles or stakes are driven into the
mud, in a series of rows about a yard apart. This palisade is then
roughly fenced in with long branches. On this structure the Mussel
spawn is deposited, and it is found that the molluscs thus produced in
the open sea are much finer than those which are bred nearer the shore.
These artificial Mussel beds are termed 'bouchots.' The fishermen who
engage in this branch of industry are known as 'boucholeurs.'
'The little Mussels,' continues M. Quatrefage, 'that appear in the
spring are known as _seeds_. They are scarcely larger than lentils,
till towards the end of May, but at this time they rapidly increase,
and in July they attain the size of a haricot bean. They then take
the name of _renouvelains_, and are fit for transplanting. For this
purpose they are detached from those _bouchots_, which are situated
at the lowest tide mark, and are then introduced into the pockets or
bags made of old nets, which are placed upon the fences that are not
quite so far advanced into the sea. The young Mussels spread themselves
all round the pockets, fixing themselves by means of those filaments
which naturalists designate by the name of byssus. In proportion as
they grow and become crowded together within the pockets, they are
cleared out and distributed over other poles lying somewhat nearer
to the shore, whilst the full-grown Mussels which are fit for sale
are planted on the _bouchots_ nearest the shore. It is from this part
of the Mussel bed that the fishermen reap their harvest, and every
day enormous quantities of freshly gathered Mussels are transported
in carts or on the backs of horses to La Rochelle and other places,
from whence they are sent as far as Tours, Limoges, and Bordeaux....
The following data, which were collected by M. D. Orbigny more than
twenty years ago, will show how important this branch of industry
must be to the district in which it is cultivated. In 1834 the three
communes of Esnandes, Charron, and Marsilly, representing a population
of 3000 souls, possessed 340 _bouchots_, the original cost of which
was valued by M. D. Orbigny at 696,660 francs; the annual expenses of
maintaining them amounted to 386,240 francs, including the interest of
the capital employed, and the cost of labour, which, however, is spared
to the proprietor who works on his own account. The nett revenue is
estimated at 364 francs for each _bouchot_, or 123,760 francs for the
three communes. Finally, the expense of the carts, horses, and boats,
employed in transporting the Mussels, then amounted annually to 510,000
francs; but these numbers are far from representing the expenses
or profits at the present day. At the time M. D. Orbigny lived at
Esnandes, the _bouchots_ were only arranged in four rows; now however,
there are _no less than seven rows, and some of them measure more than
1000 yards from the base to the summit_. The whole of these _bouchots_,
which were at first limited to the immediate neighbourhood of the three
villages, of which I have already spoken, extend at the present day
uninterruptedly from Marsilly far beyond Charron, and _form a gigantic
stockade for two miles and a half in breadth, and six miles in length_.'
A curious circumstance connected with the Mytilus remains to be
described. Let the reader, who may be so fortunate as to possess a
good microscope, cut away a portion of the fleshy part of the Mussel,
then place it in a watch glass, and examine it through that 'portal
to things invisible,' and, unless I am much mistaken, he will own the
sight to be supremely wonderful. Some water being deposited in the
glass the fleshy object will be seen to swim about in a most singular
and mysterious manner, while a close inspection shows every portion of
it to be in active motion.
This motive power is caused by countless cilia, the rapid vibration of
which creates constant currents. This action preserves the health of
the poor mollusc by ærating the water which passes over his respiratory
organs.
That some such wonderful contrivance is adopted, for conveying food
within the valves, too, is evident, when we consider that the Mussel
is always affixed to some foreign substance, that it cannot hunt after
prey, and therefore can subsist only upon whatever nutritious particles
may be contained in the element in which it lives. These consist of
minute animalculæ, principally crustacea, which are drawn within the
shell by powerful currents.
I have often watched this phenomenon through a hand lens, and have
seen the young shrimps and skip-jacks, for instance, notwithstanding
the nimbleness of their movements, irresistibly drawn into the gulf
of destruction. Even tolerably sized specimens that were seated in
fancied security upon a valve of the Mussel, have suddenly been drawn
in, out of sight. As an instance of the power of these currents, I may
state that the water in a small aquarium is often seen to be affected
by the respiratory action of a single bivalve. The same thing has even
been apparent to the writer, while watching the movements of a colony
of Barnacles attached to a Limpet, the most distant part of the fluid
being gradually drawn near, in obedience to the beck of these delicate
and graceful little creatures.
CHAPTER XII.
Terebella figulus.
(THE POTTER.)
'Whether progressing on the solid surface, or moving through the
water, or tunneling the sand, advancing or retreating in its tube,
the Annelid performs muscular feats distinguished at once for their
complexity and harmony. In grace of form the little worm excels the
serpent. In regularity of march, the thousand-footed Nereid outrivals
the Centipede. The leaf-armed Phyllodoce swims with greater beauty of
mechanism than the fish; and the vulgar earthworm shames the mole in
the exactitude and skill of its subterranean operations. Why, then,
should the "humble worm" have remained so long without a historian? Is
the care, the wisdom, the love, the paternal solicitude of the Almighty
not legible in the surpassing organism, the ingenious architectures,
the individual and social habits, the adaptation of structure to the
physical conditions of existence of these "degraded beings?" Do not
their habitations display His care, their instincts His wisdom, their
_merriment_ His love, their vast specific diversities His solicitous
and inscrutable Providence.'--DR. WILLIAMS.
[Illustration:
1 THE POTTER (_Terebella figulus_)
2 _Terebella littoralis_]
XII.
Having visited the sea-side a few weeks since, along with some
'aquarian naturalists,' among other objects we managed to capture
a very fine _Terebella Figulus_, commonly called the 'Potter.' The
specimen measured about five inches in length, and was nearly as
thick as a common drawing pencil. I could discover no signs whatever
of any tube in the rocky basin in which the Annelid was situated, a
circumstance that struck me as being rather curious.
On returning home, my much-valued prize was placed in a tumbler of
large dimensions, the base of which I strewed with newly-pounded shells
and gravel. By the following morning all the fine or powdered portion
of the 'Silver Willies' had been collected and used in the construction
of a tube, sufficient in length to cover half the contracted body of
the industrious little mason. After labouring for a fortnight, the tube
was gradually extended across the bottom of the vase in a cylindrical
form, but eventually it assumed a semi-circular shape, being built
upon the glass, and elevated by gentle stages up each side of the
vessel until the level of the water was reached, when all further
labours ceased for a time.
After the lapse of a few days the building operation was resumed,
and the tube carried fully an inch further, at right angles to its
former position. The opposite end of the structure was next extended
at an angle of 45° from the base of the vase, to a height of about two
inches. Then commenced a very curious phenomenon. Some of the tentacles
were incessantly elevated and extended across the vessel, until they
touched the opposite end of the tube, with what object I could not then
conceive. The design, however, was afterwards made evident: in less
than two days the animal succeeded _in making both ends of its tube
meet together, so as to form a continuous circle_. I happened to be
watching the mason, when the last stroke of his labial trowel was given
to the building, and shall never forget the cautious way in which the
animal crept for the first time over the newly-completed portion of the
work, and the seeming delight with which it continued to glide, hour
after hour, over the entire circuit of its dwelling-place.
Sometimes its body would be long drawn out, until the tips of the
tentacula would reach, and apparently tickle the extreme point of the
tail; then a race would commence, in character exactly resembling
that so often witnessed with the kitten, or the playful whelp, when
either of these animals foolishly imagine that the tip of their tail is
adorned with some coveted tit-bit.
The branchial organs of my specimen were very beautiful objects, being
formed of three blood-red spiral tufts, the effect of which were
heightened by their being placed in contact with the drab, coloured
cephalic[10] tentacles, which seemed to be almost innumerable. These
latter organs, although apparently so useless when seen closed, are in
reality of the greatest importance to the _Terebella_, for they not
only act as auxiliary organs of respiration, and aid most materially
in building its dwelling-place, but also constitute the real organs of
locomotion.
[10] Cephalic, belonging to the head.
'They consist,' says Dr. Williams, 'of hollow flattened, tubular
filaments furnished with strong muscular parietes. The band may be
rolled longitudinally into a cylindrical form, so as to enclose a
hollow cylindrical space, if the two edges of the band meet, or a
semi-cylindrical space if they only meet imperfectly. This inimitable
mechanism enables each filament to take up and firmly grasp _at any
point of its length_ a molecule of sand, or, if placed in a linear
series, a row of molecules. But so perfect is the disposition of the
muscular fibres at the extreme free end of each filament, that it is
gifted with the twofold power of acting on the sucking and muscular
principle.
'When the tentacle is about to seize an object, the extremity is
drawn in, in consequence of the sudden reflux of fluid in the hollow
interior. By this movement a cup-shaped cavity is formed, in which
the object is securely held by atmospheric pressure. This power is,
however, immediately aided by the contraction of the circular muscular
fibres. Such, then, are the marvellous instruments by which these
peaceful worms construct their habitation, and probably sweep their
vicinity for food.'
The foregoing beautifully and accurately describes the tentacular
cirri. The use of these organs in the formation of the tube in which
the Annelid dwells, I will now endeavour to make clear, from close
personal observation.
It is an extremely interesting sight to watch a Terebella extend its
tentacles in all directions in search of building materials, catching
up the surrounding molecules (sometimes visible along the whole length
of each filament), and then, by a strong muscular contraction, bringing
the collected atoms to the opening of the tube, around which, as is
generally supposed, they are then immediately attached by a secretion
which is exuded from the body of the animal. Such, however, is not the
case.
When the filaments bring their 'subscriptions,' the material thus
gathered, instead of being used at once for building purposes, _is,
in reality, first eaten by the animal, and, after undergoing a kind
of mastication, becomes coated with a salivary secretion, and is then
ejected in mouthfuls at the extremity of the tube_, which, by such
means, becomes gradually elongated. The shell work, when deposited as
above mentioned, is held in position, and prevented from falling over
the outside of the cavity, by the filaments which are made to hang
down in a most ingenious manner; the animal, at the same time, putting
itself in motion, allows the slimy surface of its body to press and
rub against the new addition to the tube, which is thus effectually
strengthened and soldered together.
The animal does not always wait until the opening of the tube is
reached, but gently disgorging while lying at its ease, it then pushes
forward by aid of its head and tentacles the mass of building material,
which soon becomes distributed and moulded to its proper shape.
If your specimen should happen to build a complete tube, its mode of
working cannot be well seen; but should it economize its labours, and
run its house up in a semi-circular form against the transparent side
of the vessel, as the animal I write of did, you will be enabled to see
distinctly every movement that goes on in the interior.
It seems somewhat singular that the Terebella should possess the power
of turning itself within its tube, so as to be able to extend its
habitation from either end at will. I have very often watched the
operation with emotions of pleasure, not unmixed with wonder.
Wishing to test the powers and intelligence of my specimen, I
dropped within its tube, which was curved in shape lengthways, some
particles of sand, and a pebble which nearly filled up the 'bore' of
the cylinder. The great annoyance occasioned by this intrusion to
the master of the house was painfully evident. For a whole day the
Terebella endeavoured to push out the objectionable matter by means of
its head and cephalic tentacula, but without success; for although the
mass frequently neared, it never touched or toppled over the mouth of
the aperture, and consequently fell to its original position at the
bottom of the tube as soon as the animal removed the pressure.
Apparently despairing of its efforts, though still oftener repeated,
being eventually prosperous, the poor Annelid literally 'turned tail,'
and very coolly proceeded to elongate the opposite end of its dwelling.
This operation did not last long; for in the course of a few hours, on
peering again into the vessel, I saw that the humble and insignificant
worm had mustered up courage to 'face the enemy' once more, and had,
in fact, apparently conceived a new idea, the wisdom of which was
soon made palpable; for slowly, but surely, most of the arenaceous
particles were eaten, and nothing being left but the pebble, it was
speedily and triumphantly ejected from the tube, and the sand soon
after employed for building purposes. The Terebella having completed
its laborious and well-executed task, seemed to be quite exhausted, and
lay to all appearance lifeless for the succeeding four and twenty hours.
When walking along the sandy beach, myriads of peculiar objects may be
seen swayed to and fro by the roll of the waves. Frequently, when the
tide has receded, these tubes remain sticking out of the sand to the
height of two or three inches, each terminating in a tuft, like the end
of a piece of cord that had been teazed out.
Within such a fragile habitation dwells the _Terebella littoralis_,
the most common species of the marine tubiculous Annelids. I have very
often tried, by aid of my fingers only, or a strong spade, to capture
one of these creatures, but have never been successful, even in a
solitary instance. Yet several authors tell their readers the task is
perfectly easy. Mr. Lewes, for instance, made me feel ashamed of my
previous manipulative efforts when I read his vivid description of a
Terebella hunt, and caused me lately to journey a distance of six miles
to try my hand again, with no better result than hitherto.
I have lately seen a specimen of _T. littoralis_ which a friend of
mine was so fortunate as to capture. The tube of the animal, instead
of being in its usual position, was situated in a pool, and offered a
most rare prize to its discoverer, it being the only one he had ever
caught. The tube, being of great length, was cut down to about six
inches and transferred to a shallow glass tank, in which was introduced
some pounded shells. The beautiful Annelid soon made itself at home,
and commenced to repair the damage done to its habitation by collecting
these particles, by means of its tentacula, which were thrown out to an
extraordinary distance in all directions.
The result of the animal's labours was soon apparent by a most amusing
white patch being added to each end of its dark tube.
As soon as this operation was completed _mon ami_ carefully tore up
the patched garment, and ejected the defenceless Terebella into the
vessel, wherein was placed a piece of glass tube that measured an
inch in length. Strange to state, the animal instantly crept into
this object, and soon made itself quite at home and comfortable. When
the building materials were placed near, they were collected and
_attached to each end of the glass cylinder_ by the little architect,
who doubtless was the first of its 'family' who could boast of such a
noble mansion,--which ultimately assumed a very remarkable aspect from
the variously-coloured 'mortar' that was employed in its construction.
Above and below the transparent centre came patches of red, white, and
blue material, composed respectively of broken tile, pounded shells,
and coloured glass. Such a 'concourse of atoms' was surely never before
combined, either 'fortuitously' or otherwise, in the construction of so
common an object as the tube of an Annelid.
The branchiæ of the above mentioned specimen presented a most exquisite
appearance, resembling the perfect skeleton of a leaf, supposing that
to be dyed a brilliant crimson colour, and made to exhibit incessant
life-like motion even in its most delicate and minute ramifications.
CHAPTER XIII.
Acalephæ.
(MEDUSÆ, OR JELLY-FISH.)
'And now your view upon the ocean turn,
And there the splendour of the waves discern;
Cast but a stone, or strike them with an oar,
And you shall flames within the deep explore;
Or scoop the stream phosphoric as you stand,
And the cold flames shall flash along your hand,
When lost in wonder, you shall walk and gaze
On weeds that sparkle, and on waves that blaze.'
XIII.
There are certain narrow-minded persons who raise objections to men
of science prying into the secrets of nature, and profanely, as they
think, attempting to explain the design and purpose of the great
Creator.
But to the intelligent and right thinking man, no employment could
be found more elevating or ennobling than this; and whether he be a
fellow-worker himself, or merely an approving observer of the labours
of others, still he feels, and conscientiously believes in the words of
Milton, that--
"The desire which tends to know
The works of God, thereby to glorify
The great Workmaster, leads to no excess
That merits blame, but rather merits praise
The more it seems excess."
When such a one contemplates the atmosphere, for instance, with its
'wonderful phenomena of clouds, rain, and sunshine, that alternately
shield, moisten, and warm the face of the earth, he feels awed by the
grandeur of the exquisite system of machinery by which such beautiful
results are accomplished. To him also the sea, with its physical
geography, becomes as the main-spring of a watch; its waters, and its
currents, and its salts, and its inhabitants with their adaptations,
as balance wheels, cogs, and pinions, and jewels. Thus he perceives
that they too are according to design; that they are the expression of
one thought, a unity with harmonies, which one intelligence only could
utter.' To his eye all created things possess an interest doubly great,
not only from their marvellous structure, but from the mission they are
destined to fulfil in this lower world.
What peculiar mission the Acalephæ (which we are now about to consider)
were destined to fulfil it has long puzzled men of science to explain.
Nor can this be wondered at, when we remember the amazing number of
these creatures, and also the extreme delicacy of their structure.
Some indeed appear almost as if they were formed by the sportive
combination of air and water, as if the sea-breeze ruffling the face of
ocean caused bubbles innumerable to arise, which becoming mysteriously
endowed with life, thenceforth existed as Medusæ.
They have, indeed, frequently been spoken of as 'animated sea-water,'
or 'living jelly.' These expressions seem most appropriate when we
remember, that if one of these creatures be placed upon a plate of
glass, and allowed to remain exposed to the sun's rays, the only
thing that will remain to testify to the existence of this singularly
graceful object is a thin film, that a stroke of the sponge or finger
will remove in an instant.
The most satisfactory explanation that has been offered as to the use
and purpose of the Medusæ is, that _they serve as the principal food of
whales and other Cetacea_. To these marine monsters--frequently found
from 70 to 110 feet long--we can imagine a few hundreds of jelly-fish
would be considered a small meal. The supply, however, is ever equal to
the demand, as we shall see hereafter.
I may here be permitted to explain that, in most large fishes, the
jaws are completely filled with formidable teeth, as in the shark,
for instance. This rapacious monster--which has been aptly termed the
tiger of the sea by us, and which the French, in allusion to the deadly
character of its habits, have named Requin, or Requiem, the rest or
stillness of death--possesses a most marvellous dental apparatus.
Its teeth are not, as might be supposed, fixed in sockets, but attached
to a cartilaginous membrane. The teeth, in fact, are placed one
behind the other in a series of rows; the first of which, composed of
triangular cutting teeth, stands erect and ready for use. But as the
membrane continues to grow and advance forward, it slowly perishes,
and the teeth drop off, their place being taken by the next row which
formerly stood second. These, in the course of time, are succeeded by
a third series, which are again followed by others.
Now, whales possess no such weapons. Their enormous mouths are not
filled with 'tusks or grinders, but fitted instead with vast numbers of
oblique laminæ of a softer substance, usually denominated whalebone,
which is admirably adapted for the crushing and masticating of soft
bodies.'
To give an idea of the amazing extent of the harvests of 'whale food,'
as the Medusæ are termed, that abound in various parts of the ocean,
we need only quote the evidence of various navigators on the subject.
One (Lieut. Maury), for example, states, that on the coast of Florida
he met with a shoal of these animals, that covered the sea for many
leagues, through which his vessel, bound for England, was five or six
days in passing. The most singular part of the story is that, on his
return some sixty days after, he fell in with the same shoal off the
Western Islands, and here again he was three or four days in getting
clear of them.
The Western Islands here mentioned are, it seems, the great resort for
whales; and 'at first there is something curious to us in the idea
that the Gulf of Mexico is the harvest field, and the Gulf Stream
the gleaner which collects the fruitage planted there, and conveys
it thousands of miles off to the living whales at sea. But, perhaps,
perfectly in unison is it with the kind and providential care of that
great, good Being who feeds the young ravens when they cry, and caters
for the sparrow.'
But Dr. Scoresby, in his work on the Arctic Regions, by aid of figures
conveys the most vivid idea of the myriads of these creatures that
float in the bosom of the ocean. This writer discovered that the
olive-green colour of the waters of the Greenland sea was caused by the
multitudes of jelly-fish contained therein. On examination he found
that 'they were about one-fourth of an inch asunder. In this proportion
a cubic inch of water must contain 64; a cubic foot, 110,592; a cubic
fathom, 23,887,872; and a cubical mile, 23,888,000,000,000,000! From
soundings made in the situation where these animals were found, it
is probable the sea is upwards of a mile in depth; but whether these
substances occupy the whole depth is uncertain. Provided, however, the
depth which they extend be but 250 fathoms, the above immense number
of one species may occur in a space of two miles square. It may give
a better conception of the amount of Medusæ in this extent, if we
calculate the length of time that would be requisite with a certain
number of persons for counting this number. Allowing that one person
could count 1,000,000 in seven days, which is barely possible, it would
have required that 80,000 persons should have started at the creation
of the world to complete the enumeration at the present time! What a
prodigious idea this fact gives of the immensity of creation, and of
the bounty of Divine Providence, in furnishing such a profusion of life
in a region so remote from the habitations of man. But if the number of
animals be so great in a space of two miles square, what must be the
amount requisite for the discolouration of the sea through an extent of
perhaps 20,000, or 30,000 square miles.'
These creatures may be appropriately termed the glow-worms of the
ocean, for it is to them that the phosphorescence of the sea is mainly
attributable.
Sir Walter Scott, in his poem of the 'Lord of the Isles,' thus alludes
to this phenomenon:--
'Awaked before the rushing prow,
The mimic fires of ocean glow.
Those lightnings of the wave.
Wild sparkles crest the broken tides,
And, flashing round the vessel's sides,
With elfish lustre lave;
While far behind their livid light
To the dark billows of the night
A gloomy splendour gave.'
Hugh Miller also gives a beautiful prose description of the luminosity
of our own seas, but we must resist the temptation to introduce it here.
The appearance of the Greenland Seas is principally owing to the
presence of the minute species of Acalephæ, but there are many others
that grow to an immense size. Specimens of these may be frequently seen
cast on the sea-beach by the force of the waves. When in their native
element they form the swimmer's dread, owing to a peculiar stinging
power which they possess.
The Medusæ have been divided into groups, and distinguished according
to their different organs of locomotion. The common idea is that all
jelly-fishes are like mushrooms or miniature umbrellas. Such, it is
true, is their general form, but others abound both in our own and
in foreign seas, that possess a totally different appearance. For
instance, some move by means of numerous cilia, or minute hairs that
are attached to various parts of their bodies. By the exercise of these
organs the creatures glide through the water, and hence they are called
_ciliograde Acalephæ_.
One of the most remarkable examples of this class is seen in the
Girdle of Venus (_Cestum veneris_). 'This creature is a large, flat,
gelatinous riband, the margins of which are fringed with innumerable
cilia, tinted with most lively irridescent colours during the day,
and emitting in the dark a phosphorescent light of great brilliancy.
In this animal, too, which sometimes attains the length of five or
six feet, canals may be traced running beneath each of the ciliated
margins.'
This animal, as it glides rapidly along, has the appearance of an
undulating riband of flame. Most likely it is the species to which
Coleridge alludes in the following passage:--
'Beyond the shadow of the ship
I watched the water snakes
They moved in tracks of shining white,
And when they reared, the elfish light
Fell off in heavy flakes.
* * * * *
Within the shadow of the ship
I watched their rich attire--
Blue, glossy green, and velvet black,
They curled and swam; and every track
Was a flash of golden fire.'
Another of this class is the common Beroë (_Cydippe pileus_); its body
is melon-shaped, and covered over by rows or bands of cilia, placed
similarly to the treads on a water wheel, one above another. These are
entirely under the will of the little gelatine. It can use each or
all of them, and thus row itself along at pleasure. But perhaps the
most singular portion of this creature is what has been termed its
fishing apparatus, though by some writers it is considered merely to
be the means by which the Beroë anchors its body to any desired spot.
It consists of two exceedingly slender filaments or streamers, which
measure many times the length of the Beroë itself. Some writers, again,
fancy that these organs are used to propel the animal. This must be an
erroneous notion, for if they were cut off, the creature would still
continue to move with the same power as before. Nay more, if the little
Cydippe be cut into pieces, and the ciliated bands be attached to
each fragment, the latter will swim about with the same power as when
connected with the entire animal.
From the filaments here described, others more slender still depend at
regular intervals, which curl up like vine tendrils upon the principal
stem. The whole can be spontaneously elongated or slowly withdrawn
within the body of the Beroë, where they lie enclosed in two sheaths
until again required for use.
These interior 'sheaths,' which resemble in shape the drone of a
bag-pipe, are easily seen, being almost the only parts which are not
perfectly transparent. They are whitish in colour, and semiopaque.
(Plate 6 contains a sketch of the Beroë, drawn from nature.)
I may mention that the paddles, with their comb-like array of cilia,
flap successively in regular order from the top to the bottom of each
row. This wave-like movement takes place simultaneously in all the
rows, when the animal is in full vigour.
The organs of progression in the _Pulmonigrade_ Acalephæ, as their name
imports, bear certain resemblance to the lungs in respiration. They
move by the expansion and contraction of their umbrella-shaped bodies.
Graceful and elegant indeed are the motions of these creatures. I have
seen small specimens about the size of a sixpence, advance, in three
springs, from the bottom to the top of a large vase in which they were
confined.
In descending they turn over and allow themselves to sink gradually as
if by their own weight.
The third division of the Acalephæ is termed _Physograde_. The most
common member of this group is the _Physalus_, so well known to all
sailors under the name of the Portuguese Man-of-War. It is buoyed up
by air bladders--in fact, its entire body appears as one bladder, which
the animal is enabled to contract or expand at will. At first glance
the _Physalus_ appears to belong to quite a different family--suffering
under some maltreatment; for from its lower side, what seem a number of
entrails, of all shapes and sizes, hang down. When the upper surface
or crest of its swimming bladder projects above the waves, it has a
beautiful appearance, spangled with rays of purple, blue, and gold.
This formation acts as a kind of sail, by means of which the creature
is enabled to glide along with considerable speed.
This Physalus is a somewhat mysterious being, and zoologists have not
as yet been able to determine many points connected with its structure
and development.
The _Cirrigrade_ Acalephæ, too, are a singular family. They exhibit a
higher stage of development than those already alluded to, and possess
a kind of skeleton embedded within their gelatinous bodies.
The _Porpita_ and _Velella_ are examples of this class, but for
detailed descriptions I must refer the reader to larger works which
treat on the subject.
I cannot conclude this brief and imperfect sketch of the Acalephæ
without noticing their singular mode of reproduction. Nothing can
appear more marvellous than this process when first brought before
one's attention. It far excels the wildest dreams of fiction; and were
it not so well authenticated by naturalists who have devoted labour and
valuable time to gain ocular demonstration of the fact, we might well
hesitate to believe the statements laid before us in their works.
For example, a Polype, as _Hydra Gelatinosa_ or _Hydra Tuba_(found
on buoys, oyster shells, &c., long submerged), will, it may be in a
simple aquarium, produce a number of small objects which, on being
examined through the microscope, are found to be, not young Polypes,
but Jelly-fish! In process of time, the latter, by a wondrous law of
nature, will produce in their turn, not Medusæ, but Polypes!
'Imagine,' says Mr. Lewes, 'a lily producing a butterfly, and the
butterfly in turn producing a lily, and you would scarcely invent
a marvel greater than this production of Medusæ was to its first
discoverers. Nay, the marvel most go further still, the lily must first
produce a whole bed of lilies like its own fair self before giving
birth to the butterfly, and this butterfly must separate itself into a
crowd of butterflies, before giving birth to the lily.'
Let me now, by entering briefly into detail, endeavour to make the
reader acquainted with the leading features of this mysterious subject,
known as 'the alternation of generations.'
The adult Medusæ, then, gives birth to a number of oval gemmæ or buds,
appropriately so called by most writers, which appear like minute
jelly bubbles, covered with numberless vibratile cilia. These organs,
ten thousand times more delicate, we may imagine, than the eyelashes
of some infant member of fairy land, are ever in constant motion. The
currents produced thereby serve to propel the little animal to some
stray pebble or stalk of sea-weed, situated at a respectful distance
from its gelatinous relative. On some such object the young bud
attaches itself, and proceeds to vegetate.
The body gradually lengthens, and becomes enlarged at its upper
extremity; from this portion of the animal four arms appear surrounding
a kind of mouth. The arms lengthen, and are soon joined by four others.
These organs, as also the inner surface of the lips and of the stomach,
are covered with cilia, and become highly sensitive. They are used
in the same manner as the tentacula of the Actiniæ, namely, for the
capture of food. There is this difference, be it observed, between the
two animals, that while the infant Medusæ labours incessantly to gain
its daily meals, the zoophyte remains still, and trusts to chance for
every meal that it enjoys.
Fresh sets of arms continue to be developed successively upon the
little jelly fish, until the whole amount in number to twenty-five or
thirty. 'And the body, originally about the size of a grain of sand,
becomes a line, or the twelfth part of an inch in length.'
Thus far there appears nothing particularly striking or improbable in
the history of the Medusæ; the next stage, however, exhibits matter for
our 'special wonder.'
The young Acaleph now throws off its animal existence, and sinks into a
plant or compound polype.
The lower part of the body swells, and from thence, what may be termed
a _stolen_, is thrown out. On the upper surface of the stolen one
and even two buds are often formed. 'As the bud enlarges it becomes
elongated, and bends itself downwards to reach the surface of the stone
to which the elongated extremity adheres; after this the attached end
is gradually separated from the body of the parent. When thus detached,
a small opening presents itself at its upper end, its interior
gradually becomes hollowed out, and cilia grow upon it, and tentacula
begin to sprout around the mouth, exactly in the same manner as in the
buds formed on the upper surface of the stolens.'
Thus, from a single bud numberless other buds are formed, each being
endowed with equally prolific powers. If the parent be cut in half
transversely, the cut will close in, attach itself to some object, and
produce stolens and buds! If cut longitudinally, and the cut edges
be allowed to touch each other, they will again adhere, and exhibit
no trace of their ever having been divided. If the cut edges of each
division be not kept apart they will approximate and adhere together,
and thus two separate animals will be produced, each gifted with the
power of throwing out stolens and buds with the same prodigality as if
they had never been disunited!
How long this budding process of necessity continues we cannot tell. It
may be only during the winter season. These creatures in their perfect
condition are generally found crowding our seas during the summer
months; most probably, therefore, as Sars and Steenstrup state, it is
at the commencement of spring that they undergo the last portion of
this 'transformation strange.'
Still, this cannot be taken as a general rule. Dr. Reid, who for a
period of two years kept colonies of Medusæ, and assiduously watched
the various stages of their development, found that the larvæ of
one colony, which was obtained in September 1845, did not split
transversely into young Medusæ in the spring of 1846, as he expected
them to do, but continued to produce stolens and buds abundantly.
On the other hand, the larvæ of the other colonies, which this
gentleman obtained in July, began to yield young Medusæ about the
middle of March. This process takes place in the following manner:
A 'bud' having arrived at maturity, it becomes 'cylindrical,'
considerably elongated, and much diminished in diameter, its outer
surface being marked with a series of transverse wrinkles.
These wrinkles, or rings, which frequently amount to thirty or forty
in number, are first formed at the top, and slowly extend downwards.
Gradually as these furrows become deeper, the tentacula waste away, and
upon the margin of the upper ring eight equi-distant rays are formed.
The process continuing, in the space of a fortnight or so each groove
or ring is in like manner furnished with rays. The Medusæ now present
an appearance exactly resembling a series of cups piled up one within
the other. Strange to state, each little cup becomes eventually endowed
with life! As the uppermost segment is completely developed, it rests
upon the slender lips of the one beneath. It then glides off from its
old resting-place, and swims freely about in the water. Quickly it
aspires to the rippling surface above, and by a series of graceful
evolutions accomplishes its object. Once among the dancing waves and
exposed to the rays of a cheering sun, our little Medusa assumes its
complete form; and as a beautiful _Modecra formosa_, it may be destined
at some time or other to be the prize of an ardent zoologist, who, I
venture to assert, could not compliment it in more poetical language
than Professor Forbes has already done. This delightful author,
describing the little gem in question, says, 'It is gorgeous enough
to be the diadem of sea fairies, and sufficiently graceful to be the
night-cap of the tiniest and prettiest of mermaidens.' Or as an adult
_Cyanea capillata_, our once insignificant jelly-bag may perhaps
appear, and by an exercise of its urticating powers, send some unhappy
swimmer smarting and trembling to his home.
While the Medusæ column proceeds to throw off from its uppermost part
living segments of itself, its lower half, or stem, continues to grow,
but does not become ringed, for as the budding process ceases, the last
formed cup rests on newly-formed tentacula! Then again stolens are
thrown out, on which young Medusæ are formed, as before described.
Contemplating such mysteries as these, the mind becomes bewildered and
the spirits humbled.
'Imagination wastes its strength in vain,
And fancy tries and turns within itself,
Struck with the amazing depths of Deity.'
The above may be deemed one of the most interesting zoological theories
that has ever been promulgated in modern times. It was founded by
Chamisso, and termed the 'alternation of generation,' but was much
improved and extended by the researches of Steenstrup. Professor Owen,
however, had previously reduced the theory to a fixed and definite
scientific form, under the title of '_Parthenogenesis_.' Another
author, not viewing the Medusæ in the various stages of development
as an aggregation of individuals, 'in the same sense that one of
the higher animals is an individual,' proposes that each Medusa be
considered as an individual, developed into so many 'zooids.'
Into this abstract question, of course, I cannot enter. The reader who
would wish to know more of the subject than I have faintly shadowed
forth in this chapter, may consult Steenstrup's Memoir, published
by the Ray Society; Dr. Reid's admirable papers in the 'Magazine of
Natural History' 2d series; Lewes' 'Sea-Side Studies;' and the learned
works of Professor Owen.
[Illustration: MEDUSÆ IN VARIOUS STAGES OF DEVELOPMENT.]
CHAPTER XIV.
Doris, Eolis, &c.
'The inhabitants of the watery element were made for wise men to
contemplate and fools to pass by without consideration.'--ISAAK
WALTON.
XIV.
One fine morning during the month of January, on peering into my
largest tank I perceived, attached to the upper portion of the marble
arch (centre piece), a peculiar object that had evidently been
deposited during the preceding night, but by whom or by what means I
knew not. It resembled a fungoid growth, or riband of flesh, plaited up
and attached at one edge to the stone. At every undulation of the water
the object moved to and fro with an extremely graceful motion.
By careful and close examination it was seen to be covered with a film,
that gradually expanded until it burst, and thus gave means of escape
to thousands of minute white granules. On submitting these to the
microscope, a most wondrous sight met my astonished eyes. Each dot or
granule proved to be a transparent shell, resembling the periwinkle or
rather the nautilus in shape; containing an animal whose excited and
rapid movements were amusing to witness. From out the opening of the
shell appeared now and again two rings of cilia. When these organs
were about to be put into action, they reminded me of two circular
tubes of gas connected together, and each containing innumerable
perforations, which were sometimes suddenly and entirely lit up by a
torch being applied to one end.
The _cilia_ may be distinctly seen to play at a certain point, and then
gradually extend round the circumference of the rings. When the whole
are in full action their movements are so extremely swift _as to appear
devoid of motion_, and thus bear a resemblance to rings of flame.
The result of the movements of the cilia was always evident in
the vigorous evolutions of the little embryos, for the microscope
filaments, while in action, caused the animal to roll about in all
directions in a confined circle. When this envelope burst, the little
nautiline dashed out, and then--then it was of little use attempting to
get a view of the animal again, so rapid and violent were its movements
to and fro, never resting for one instant on any spot, and least of
all the spot wished. By the aid of blotting-paper, I sometimes reduced
the quantity of water in the watch glass; and the animal, thus being
compelled to confine its evolutions to a narrower stage, was more often
within the field of view.
On visiting the sea-shore shortly after the discovery of the egg
cluster just described, I perceived attached to numberless stones and
large boulders thick clusters, composed of the self-same objects!
Beside them were lying confused heaps of _sea-slugs_, evidently
exhausted with their hatching exertions. Anything more repulsive to
the eye than those animal heaps exhibited it would be difficult to
conceive. Yet, at the same time, I know of no sight more pleasing than
to watch the _Doris_ in its healthy state, gliding along with outspread
plume on the under surface of the water, or up the sides of the tank,
more especially if it be observed through a powerful hand lens.
These remarks will perhaps convey some new information to the young
naturalist, embracing as they do the leading facts connected with the
wondrous embryotic development of many marine animals. The reader will
already be prepared to learn that the vivacious little animal, moving
by aid of cilia and enclosed in a _shell_, was in reality the youthful
stage of that slow creeping gasteropod the _Doris_, which, in its
mature form, is possessed of no cilia, nor any shelly covering whatever.
I should not have introduced this subject so familiarly did I not feel
anxious to make my readers aware how easy it is for each of them to
conduct experiments in the early stages of embryotic development, and
to gain practical evidence of the wonders which this study unfolds.
'What,' eloquently asks Mr. Lewes, 'can be more interesting than to
watch the beginnings of life, to trace the gradual evolution of an
animal from a mass of cells, each stage in the evolution presenting
not only its own characteristics, but those marks of affinity with
other animals which make the whole world kin? To watch the formation
of the blood-vessels, to see the heart first begin its tremulous
pulsations, to note how life is from the first one incessant struggle
and progress--these keep us with fascinated pertinacity at our studies.'
The remarkable fact above mentioned, of the young of the Nudibranchiate
Gasteropoda being furnished with a shell is exhibited not only in
Doris, but in Eolis, Tritonia, Aplysia, &c., while the embryos of the
Purpura, Nerita, Trochus, &c., are likewise in their youthful state
furnished with cilia, by the agency of which these animals swim freely
about in their native element.
There is one exception to this, which occurs in _Chiton_, the early
stage of which has recently been shown by the observations of Mr.
Clarke and Professor Loven to be peculiar, and more resembling that
of an annelid than of a mollusc. In this case the animal can scarcely
be said to undergo a metamorphosis; for the embryo, even within the
egg, has nearly the form of the parent, and the appearance of the
shell-plates is a mere matter of development.
I have never attempted to count the ova that were contained in any
single riband of Doris spawn, in fact I considered the task an
impossibility; but at a rough calculation, I concluded there would not
be less than a million. Dr. Darwin, however, travelling in the Falkland
Isles, met with a riband of spawn from a white Doris (the animal itself
was three and a half inches long), which measured twenty inches in
length, and half an inch in breadth! and by counting how many balls
were contained in a tenth of an inch in the row, and how many rows in
an equal length of riband, this gentleman reckoned that upon a moderate
computation there could not be less than six millions of eggs. Yet, in
spite of such amazing fecundity, this Doris was not common. 'Although,'
says Dr. Darwin, 'I was searching under the stones, I saw only seven
individuals. No fallacy is more common with naturalists, than that the
numbers of an individual species depend on its powers of propagation.'
This apparent paradox is not difficult of explanation when we consider
the number of enemies which are always hovering near, and ready with
hungry mouths to snap up the infant embryos as soon as they begin
to show signs of vitality. The Hermit-Crabs are especially fond of
Doris spawn, so much so, indeed, that the writer could never retain
any for hatching purposes while any of the Paguri were near. Mr.
Peach says they (the young Dorides) have myriads of enemies in the
small _Infusoria_, which may be noticed, with a powerful microscope,
hovering round them, and ready to devour them the instant weakness or
injury prevents their keeping in motion the cilia, which serve both
for locomotion and defence. Let them cease to move, a regular attack
is made, and the animal is soon devoured; and it is interesting to
observe several of the scavengers sporting with the empty shell, as if
in derision of the havoc they have made.
The same difficulty of calculation does not exist, at least to any such
extent, with the spawn of Eolis, which is laid in stringy coils. M.
Gosse mentions a specimen of _E. papillosa_ that laid nine strings of
spawn in his tank between the 20th of March and the 24th of May, all as
nearly as possible of the same length. Each string contained about a
hundred convolutions, each convolution about two hundred ova, and each
ova including, on an average, two embryos, making a total progeny of
forty thousand, produced from one parent in little more than two months.
I may mention that on no occasion have I ever found the spawn coils of
either Doridiæ or Eolididæ in my tanks, or at the sea-shore, except
during the months of January and February or March; neither have any
of my specimens spawned more than once during an entire season. From
noticing the same group of parent slugs congregated, and remaining,
as I can affirm, for weeks near their egg clusters, evidently in a
most enfeebled condition, it has occurred to me that on the Frith of
Forth, at least, vast numbers of these animals do not long survive the
hatching season.
Whether this be the case or not, it is a most singular fact that
in this locality, a Doris more than one or two inches in length is
scarcely ever to be met with.
There is at present in one of my tanks a specimen of the Doris of a
pearly-white colour, a second, tinted white and pink, and two others
which are quite _black_,--all being procured from the coast near
Edinburgh. The last-mentioned animals are, I think, somewhat uncommon.
When watching one of them in motion while the sun is shining down upon
it, the hue of the creature changes from a black to a very deep purple,
owing, no doubt, to its fleshy disc being many shades lighter than its
body, which, being extended, and exhibited under a full glow of light,
becomes semi-transparent. This peculiarity is not evident, of course,
when the Doris is lying in a passive state, with all its gill-plumes
closed up.
This sombre-coated gasteropod, although rare in some localities, is
very plentiful in foreign parts, if the following may be received as
an accurate narrative. 'On a reef of rocks near the island of Raiatea
is a huge unshapely black or brown slug, here called '_Biche_,' from
six to seven inches long, and five to six broad. Is is caught in vast
quantities, and not only regarded as a great delicacy by the natives,
but being cured, has become a valuable article of commerce in the China
market, whither it is carried from many insular coasts of the Pacific
by American ships. We have seen a number of lads fill three canoes in
two hours with these sea-snails.'
Thus uninviting as this slimy animal seems to our English taste, there
is evidently no doubt of its being used by the Chinese as an article of
food, and according to the evidence of certain authors, is esteemed by
the 'barbarians' a high-class luxury; but then we must remember that
the inhabitants of the land of gongs and chopsticks, have always been
famed for their singular gastronomic tastes. One poet writes:--
'That man had sure a palate covered o'er
With brass or steel, that, on the rocky shore,
First broke the oozy oyster's pearly coat,
And risked the living morsel down his throat.'
But, 'Mandarins and Pigtails,' what was such _risk_, I ask, compared
to that which _he_ endured, who swallowed the first mouthful of
birds'-nest soup? or horror of horrors, the first spoonful of sea-snail
stew? Yet we are told that both the 'mucilage' and the _Bêches de Mer_
dishes are savoury and highly grateful to the palate of an appreciating
gourmand.
A recent author, describing a Chinese dinner from personal observation,
tells us, that when the first dish, composed of birds'-nest soup,
was over, he waited the advent of the next course with very nervous
excitement. 'It was a stew of sea-slugs. They are slippery, and very
difficult to be handled by inexperienced chopsticks; but they are most
pleasant and succulent food, not at all unlike in flavour to the green
fat of the turtle. If a man cannot eat anything of a kind whereof he
has not seen his father and grandfather eat before him, we must leave
him to his oysters, and his periwinkles, and his craw-fish, and not
expect him to swallow the much more comely sea-slug. But surely a
Briton, who has eaten himself into a poisonous plethora upon mussels,
has no right to hold up his hands and eyes at a Chinaman enjoying his
honest, well-cooked stew of _Bêches de Mer_.
'During the discussion of this dish our Chinese master of the
ceremonies solemnly interposed. We were neglecting the rudiments of
politeness, no one had offered to intrude one of these sleek and
savoury delicacies, deeply rolled in sauce, into the mouth of his
neighbour. Efforts were made to retrieve the barbarian honour, but
with no great success, for the slugs were _evasive_, and the proffered
mouthful was not always welcome.'
CHAPTER XV.
The Crab and the Dainty Beggar.
'In taking a review of most, if not all the actions of the animal
world, it must be obvious that, whether we allow them reason or not,
the actions themselves comprehend those elements of reason, so to
speak, which we commonly refer to rational beings, so that if the same
actions had been done by our fellow-creatures, we should have ascribed
them without hesitation to motives and feelings worthy of a rational
nature.'--SCHLEIDER.
'All things are bigge with jest; nothing that's plain
But may be wittie, if thou hast the vein.'
--GEORGE HERBERT.
XV.
I have been observing for several days the movements of a Common
Shore-Crab, which has been almost all his life under my protection.
Although his present dimensions would render such a feat impossible,
when first I shook the little fellow off a bunch of _C. officinalis_,
he could have crawled with the greatest of ease into the mouth of a
small popgun. We all know that members of this family are bold and
daring in their attacks upon their weaker neighbours; upon each and all
they wage a constant predatory warfare. The poor Pholades, however, are
the favourite objects of their attacks. On these innocent bivalves the
Crustacea successfully prey, unless they are protected by their usual
rock-bound citadel, which, of course, they cannot always be. In order
to watch the Pholas at work, it is necessary that the siphons should be
more or less protruding from his tubular dwelling. If supported, say,
to the full depth of his valves, the animal is secure; for I notice
that neither crab nor fish can tear away the gristly ends of the
siphonal appendages when withdrawn; and when disturbed, the poor Pholas
leaves only this part in view. I have frequently seen the Fiddler-Crab
embrace a Pholas in his claws, and struggle to pull him from his seat.
On one occasion this operation was performed successfully, much to my
annoyance, as I had been at some trouble to saw the rock away in order
to watch easily every movement of the animal within. At night when I
looked into the tank my pet was safe; next morning it was wedged under
some pebbles, and the crab was feasting leisurely upon his tender flesh.
It is most amusing to watch the Blennies, too, attack a Pholas, cast
into the tank, and to witness their mode of pecking at and shaking
their victim, and turning innumerable somersaults with it in their
mouths. The strength they exhibit in these manœuvres is perfectly
astounding.
About two hours after they had received one of their favourite
'muttons' to feast upon, I peeped into the aquarium, and found, as I
expected, the Blennies hard at their work of destruction. Behind them,
among some bushy tufts of _I. edulis_, the little crab, before alluded
to, was seated. In his arms he held an object unlike anything I had
seen on sea or land. It appeared like a slender stick of beautifully
iridescent opal. My amazement at this sight may readily be conceived,
for I had not the remotest idea as to how he had become possessed of
such a prize.
Next day I placed another devoted Pholas in the tank, and after a while
looked in to see how its finny enemies were conducting themselves,
when, what should meet my eye, but the crab, sneaking off with another
opal baton in his arms! I was more puzzled than ever. It was quite
certain that the object in question had been procured from the Pholas,
yet I had not heard of, or ever seen anything like it in that animal.
I was 'on thorns' until next day, so that I might by watching solve
the mystery. A third Pholas was flung into the den. The fishes, eager
as usual, instantly attacked and pulled the mollusc to pieces. After a
while the crab began to move about to and fro, evidently very restless,
and anxious for my departure. I did retire, but only to such distance
as would allow me a distinct view of his movements. In a few moments he
stepped out mincingly on the tips of his toes, and crossed the tank to
the spot where the poor Pholas lay, like some fine beau in Queen Anne's
reign tripping jauntily down the Mall, or across St. James' Park, to
feed the ducks in Rosamond's Pond.
The Blennies darted off at his approach. He then seated himself before
the mangled corpse, and scraped at it vigorously, manifestly searching
for some coveted treasure. Shortly after, perceiving him clutch at
something, I quickly approached and disturbed his movements--took up
the Pholas, and to my surprise found, on drawing out an object that
protruded from the foot of the animal, that I possessed the pearly and
gelatinous cylinder, such as the crab had twice before devoured with
such evident relish.[11]
[11] My first introduction to the Hyaline stylet as above narrated,
occurred in October 1858.
It was plain then that the little rascal had become so dainty, that
he 'turned up his nose,' or rather his 'pair of noses,' at what is
vulgarly termed the 'first cut,' and condescended only upon the
tit-bits, for his marine banquet. So his crabship, in order to save
himself trouble, actually waited until the fishes had cut up the
Pholas to a certain point, when he would rush forward and seize on his
favourite fare.
Some of my readers will doubtless remember the anecdote of the crossing
sweeper, whose idiosyncrasy led him to covet diurnally a mutton-chop
situated in the middle of the loin. My Lady Pepys, or Mr. Saccharine,
the great grocer, couldn't always procure the desired 'cut!'
_n'importe_ the knight of the besom met with no such disappointment.
This individual's place of business was luckily situated opposite to a
noted butcher's shop, which circumstance easily enabled him to watch
until, from the demands of sundry customers, the perspective of the
loin, which lay temptingly upon the chopping block, had become adapted
to his point of sight. He would then step in and meekly order a simple
pound avoirdupois. With this _bonne-bouche_ carefully packed in his
pocket, he would again mount guard, and remain until night. At dusk of
evening he shut up shop,--that is, he swept the dirt over the parallel
path that he had all day kept scrupulously clean, and then marched off
to enjoy his dinner at a fashionable hour, in private.
Are not these cases palpably alike? Passing by certain details, were
not the pawkiness and cunning of the epicurean beggar fully equalled by
our diminutive friend, _C. mænas_?
'But,' you ask, 'what then was the opal stick?' Ay, there's the rub,
for even the greatest naturalists cannot positively agree as to the
use and purpose of this mysterious organ. Yet it is to be found (as we
have seen) in the foot of the Pholas, in the Mussel, the Cockle; and,
in fact, it occurs in almost all bivalves both great and small. It is
termed the 'hyaline cylindrical stylet,' and is very _lucidly_ and
scientifically described as 'an elastic spring to work the corneous
plate or attritor, and by the muscular action of the foot and body, to
divide and comminute the food, and especially the minute crustaceous
and testaceous alimentary matters received into the stomachial cavity.
It appears then that this appendage acts as _a gizzard_, and the
bivalve mollusca are thus supplied with a masticatory apparatus very
analogous to the gizzards of some of the gasteropoda.'
Now, the simple fact that I have stated above, of the hyaline stylet
being found in the _foot_, and not in the stomach, at once proves
that it cannot possibly act as a _gizzard_ to the Pholas, or any other
bivalve in which it is known to exist.
In the succeeding chapter I shall endeavour, from personal observation,
to shed a slender ray of light upon the function of the stylet.
CHAPTER XVI.
The Pholas, &c.
(ROCK-BORERS.)
'He that of greatest works is finisher
Oft does them by the meanest minister.'
XVI.
At certain parts of the Scottish coast, the 'dykes,' or walls built
near the road-side, are constructed entirely of rough-hewn pieces of
hard sandstone rock, brought from the neighbouring shore. Sometimes a
dyke will extend for two or three miles, without presenting an isolated
fragment, in which the honeycomb-like perforations of certain species
of the boring Mollusca are not more or less apparent.
A fragment of soft sandstone lies before me, measuring three and a half
inches in length, and two inches in breadth, which, small though it be,
contains no fewer than seventeen cylindrical tunnels. Each of these
exhibits so wonderful a skill in construction, that human hands could
not surpass it, though aided by 'all the means and appliances to boot,'
of mechanical agency.
It is generally stated that the Pholas never intrudes itself into the
apartment occupied by a neighbouring 'worker.' The Pholas, however,
often intrudes on its neighbour; and such intrusion is manifested in
the small piece of stone alluded to in no less than four instances.
Here let me observe, that it is not always the larger mollusc that
bores through the smaller one; it as frequently happens that the latter
deserves the brand of wanton aggressor. Both cases are common enough,
and, indeed, must of necessity occur, wherever at any time a colony of
various sized Pholades are clustered together in a small portion of
rock.
A fragment of rock riddled by the Pholas is a much more pleasing
sight than can be witnessed at the sea-shore in connection with that
animal under usual circumstances. For this reason: When visiting the
habitat of the boring bivalves, a host of small circular holes are
sometimes seen; at other times the surface of the same portion of the
beach appears comparatively sound, and it is only by striking a smart
blow with a hammer upon the ground, that we render scores of orifices
instantly observable in all directions, from each of which is thrown a
small jet of water. This phenomenon is caused by the Pholades in alarm
retracting their siphons, which had hitherto filled the entire extent
of the tunnels. At such a locality, if a piece of rock be excavated,
various specimens of these boring molluscs, shrunk to their smallest
possible size, will be discovered at the base of the cavities, which
are invariably of a conical form, tapered at the top, and gradually
enlarging as they descend.
It must be evident, then, that neither the likeness of the animal, nor
the formation of its singular dwelling-place, can be seen by the casual
wanderer along the sea-shore.
It will also be apparent to the intelligent reader, that when once the
Pholas is located in a certain spot, he becomes a tenant for life;
for never by any chance whatever, can the poor miner leave his rocky
habitation by his own unaided exertions, even were he so inclined. As
he grows older and increases in size, nature teaches the animal to
enlarge his habitation in a proportionate and suitable manner.
During the period of the boring process, the orifice becomes clogged
above the shell with the _debris_ of the rock, and this, if allowed to
accumulate would speedily asphyxiate the animal. To get rid of such
an unpleasant obstruction, the Pholas retracts, and closes the end of
its siphons, then suddenly extends the 'double barrelled' tube to its
full length, until it reaches the entrance of the tunnel. This movement
often repeated, causes portions of the pulverized stone to be forced
outwards at each operation.
It is interesting to watch the curious manner in which the end of the
principal siphon is alternately closed and spread out when it reaches
the water, like a man inspiring heavily after any unusual exertion; it
is then made again to descend, and renew its task, as above described.
In extracting that portion of the _debris_ which is deposited at
the _base_ of the cavity, below the body of the industrious miner, a
different plan is adopted. Wherever a Pholas is at its labours, there
are always deposited within a circumference of several inches round the
tunnel, myriads of short thin threads, which are squirted out from the
smaller siphon.
The nodules on examination are found to be composed of pulverized
rock, which is drawn in at the pedal opening, and ejected in the
above manner, thereby effectually clearing the lower portion of the
orifice. It was suggested to me that these threadlike objects were the
fœcal matters of the Pholas, but this idea was soon dispelled by the
assistance of the microscope; and, moreover, from the fact that the
threads are never visible when the animal is in a quiescent state, but
only when it is busily engaged in its mysterious task of boring.
I was for some time puzzled to find any aperture in connection with
the club-like foot of the Pholas (_P. crispata_), although several of
the bivalves were sacrificed to the cause of science. But what the
microscope and scalpel in this instance failed to unfold, attentive
watching of the animal in the aquarium made palpably apparent, in the
following manner.
I had on one occasion captured about a dozen Pholades, some of which
were embedded in the solid rock, others detached.
The first mentioned, I knew would be quite safe among the blennies
and crabs, from the untempting and unedible nature of their siphonal
tubes. Very different was the case with the defenceless, disentombed
specimens. These were intended as food for their finny companions, who
happened to be particularly fond of a change of diet. My 'pack' had
subsisted for some time on Mussels, and on such excellent food, had
become impudent, corpulent, and dainty. But overgorged epicures though
they were, I knew that although everything else failed, a 'real live'
Pholas placed before them would serve to speedily whet their appetites.
A splendid specimen of the siphoniferous bivalve was dropped into the
tank, the base of which it had no sooner reached, than the fishes, with
eager eyes and watering mouths, came hovering like a flock of vultures
round the welcome meal thus unexpectedly placed before them.
One rascal, who seemed to be cock of the walk, came forward and made
the first grip at the delicate fleshy foot, that in appearance was as
white as a newly fallen snowflake. The pedal organ was, of course,
instantly and forcibly withdrawn, so much so, indeed, as to be almost
hidden from view, except at its extreme base. In this position it
remained for several seconds. When the finny gourmand again boldly
advanced to take a second mouthful, to my intense surprise he was,
apparently, blown to a distance of several inches. I could scarcely
credit the evidence of my senses. Another and another of the fishes
were in their turn served in like manner as their leader. In a short
time, however, the poor mollusc failed to repulse his enemies, and
finally fell a passive victim to their gluttonous propensities.
Now comes the important question, 'How is the boring operation
performed?' How can this simple animal, with its brittle shell, and
soft fleshy body, manage to perforate the sandstone, or other hard
substances, in which it lives?
For hundreds of years this query has been asked, and various are the
replies which from time to time have been given. Singular to state,
although specimens of the Pholas, and its allies the Saxicavæ, are to
be procured in abundance in many parts of the kingdom, the subject is
not even yet positively settled.
There have been many theories advanced, some the result of fancy
or guess-work; others, of practical study. All these have their
supporters, but none have, by common consent, been adopted by
physiologists as the true one.
Having for several years made this subject a study of personal
observation, I believe I may venture to state, that I have succeeded
in casting a feeble ray of light upon it; and, although the result of
my labours may not be deemed conclusive, I may at least claim some
credit for my endeavours to clear up a most difficult, though deeply
interesting point in natural history.
The various theories promulgated on this knotty point are generally
classed under five heads: 1st, That the animal secretes a chemical
solvent--an acid--which dissolves the substance in which it bores.
2d, That the combined action of the secreted solvent, and rasping by
the valves, effects the perforations. 3d, That the holes are made by
rasping effected by silicious particles studding the substance of
certain parts of the animal. 4th, That currents of water, set in action
by the motions of vibratile cilia, are the agents. 5th, and lastly,
That the boring mollusca perforate by means of the rotation of their
shells, which serve as augurs.
Of all the above, the first which is quite a fancy theory, seems to
meet with greatest favour among certain naturalists. But as it is
rather puzzling to find a chemical solvent, which will act equally upon
sandstone, clay, chalk, wax, and wood, this hypothesis can only be
looked upon by practical men as ingenious, but incorrect. Even were it
proved that the animal really possessed the power of secreting an acid
sufficiently powerful, the question naturally arises, How can the shell
escape being affected in like manner with the much harder substance in
which it is situated?
The second theory, or the combined action of rasping and the secreted
solvent, is, for obvious reasons, equally objectionable.
The third theory, which endeavours to account for the wearing away of
the rock by means of silicious particles situated in the foot and other
parts of the animal, has been for some time proved to be erroneous,
from the fact, that the combined skill of some of our best anatomists
and microscopists has failed to discover the slightest presence of any
particles of silex in the Pholadidæ, although these are believed to
exist in other families of the boring acephala.
The fourth theory, that of ciliary currents as an accessory agent in
boring, is worthy of greater consideration, chiefly from the evidence
we possess of the immense power which the incessant action of currents
of water possess in wearing away hard substances.
We come now to what may be considered the most important of the
theories above enumerated, viz., the mechanical action of the valves of
the Pholas in rasping away the rock, &c. This hypothesis is one which
most naturally suggests itself to the mind of any impartial person, on
examining, for instance, the rasp-like exterior of the shell of _Pholas
crispata_.[12] But as I shall endeavour to show, although the shell
forms the principal, it does not by any means constitute the _sole_
agent in completing the perforating process.
[12] Specimens of this species, I may mention, have always formed the
subject of my experiments, and therefore are alone alluded to in the
following remarks.
Mr. Clark, a clever naturalist, considers with Mr. Hancock that the
powerfully armed ventral portion of the _mantle_ of the closed boring
acephala is fully adequate to rub down their habitations, and that the
theories of mechanical boring, solvents, and ciliary currents, are
so utterly worthless and incapable of producing the effects assigned
to them, as not to be worth dwelling upon for one moment. Mr. Clark,
therefore, comes to the conclusion that 'the foot is the true and
sole terebrating agent in the Pholas.' This 'fact' he considers to
be 'incontestably proved,' for the following reason, viz., because
he had discovered specimens of this bivalve with the foot entirely
obliterated,--which phenomenon, Mr. Clark states, is caused by
the animal having arrived at its full growth, at which period the
terebrating functions cease; and as 'nature never permanently retains
what is superfluous,' the foot is supposed gradually to wither away,
and finally disappear.
This, I suspect, is another 'fancy' theory. Although I have excavated
hundreds of Pholades, some of giant-like proportions, it has never
been my lot to witness the foot otherwise than in a healthy and fully
developed condition.
Another writer, having no opportunity of viewing the living animal,
does not consider it difficult to imagine the Pholas 'licking a hole'
with its foot, from the fact that he (Mr. Sowerby) managed to make 'a
sensible impression' upon a piece of kitchen hearthstone. 'I had,' he
says, 'not patience to carry the experiment any further, but as far
as it went, it left no doubt on my mind that, with the foot alone,
and without any silicious particles, without a chemical solvent, and
without using the rasping power of its shell, our little animal could
easily execute his self-pronounced sentence of solitary confinement for
life.'
Such an inconclusive statement as this would, I feel certain, never
have been penned, had its author been so fortunate as to have had
opportunity of watching a Pholas at work.
But, as Professor Owen truly observes, 'Direct observation of the
boring bivalves in the act of perforation has been rarely enjoyed, and
the instruments have consequently been guessed at, or judged of from
the structure of the animal.' Such, evidently, is the case with Mr.
Sowerby, and several other writers who treat on this subject.
Here we may call attention to the folly of naturalists endeavouring
to tag a pet theory upon all the boring acephala, to the exclusion of
every other. Such a system is defended upon the principle that, 'it
is much more philosophical to allow that animals, so nearly allied as
these in question, are more likely to effect a similar purpose by the
same means, than that several should be adopted. Surely this is more
consistent with the unity of the laws of nature, and that beautiful
simplicity which is everywhere prevalent in her works.'
How much more shrewd and philosophical are the opinions of such a man
as Professor Owen, who, when speaking of the mechanical action of the
valves of _P. crispata_, says, 'To deny this use of the Pholas shell,
because the shell of some other rock-boring bivalves is smooth, is
another sign of a narrow mind.' Again, this learned author forcibly
remarks, in direct opposition to the writer previously quoted, '_The
diversity of the organization of the boring molluscs plainly speaks
against any one single and uniform, boring agent at all_!'
The more I study this subject, the more does the truth of the
last-mentioned statement become apparent to my mind.
An examination of engravings of the shells, or even of the Pholas
itself, when lying loose in the tank, or quietly seated in the rock,
extending and retracting its siphons, fails to give one the slightest
idea of its extraordinary appearance when enlarging its dwelling. At
such times it seems to be a totally different animal, and to have
suddenly acquired a most marvellous degree of power, energy, and
perseverance, forming a striking contrast to its usual quiet, passive
habits.
In the first place, as I have elsewhere written, it retracts its tube
to, and even under, the level of its shell, just as a man, about to
urge onwards some heavy mass with his shoulders, would depress his
head to increase and concentrate his muscular power. Then follows an
expansion of the neck or upper part of the ventral border, from whence
the siphons protrude. This movement closes the posterior portions of
the valves below the hinge, and brings their serrated points together.
The next act on the part of the animal is to place its foot firmly
at the base of the hole; when leaning forward, it makes a sweeping
movement fully half round the cavity, pressing firmly-upon the umboes,
which nature has strengthened for the purpose by two curved teeth
fixed on the inside of the valves. At this stage it again reclines on
its breast, and tilting up the shell as much as possible, it makes
another motion round to its former position, leaning upon its back. By
these intricate movements, which the Pholas appears to accomplish by
a contraction almost painfully strong, it opens the rasping points of
the valves. These execute a very peculiar scooping movement at the base
of the cavity, and the animal having got so far, prepares itself for
further exertion by a short rest.
The specimen whose movements I have attempted to describe, lived in
my possession for a considerable time. It bored so completely through
the piece of rock in which it was embedded, that the whole of its foot
dropped through the aperture, and remained in this position for months,
the animal, in consequence, being unable to change its position even in
the slightest degree. Each movement of this specimen, both before and
while the hole at the base of the cavity was gradually being enlarged,
was watched, and every striking and interesting feature that occurred
noted down at the moment. Various queries were put and answered, as
far as possible, by direct ocular demonstration of the labours of the
animal in the vase before me.
I consider myself to have been singularly fortunate in being able
to view the actions of the creature from beneath, in consequence of
the hole being bored through the rock. This circumstance allowed me
distinctly to see what was going on at the base of the orifice.
My early observations have fortunately been confirmed in other captive
Pholades, which at various periods have been domesticated in my tanks.
I am convinced, then, that the shell forms the _principal_ agent in
boring the animal's dwelling, without either acid or flinty particles.
The late lamented Professor Forbes held that if this were the case,
the rasping points on the surface of the valves would soon be worn
down,--an appearance which, he says, is never seen. With all respect
for such an eminent name, I must state that he was in error. Not only
are the edges at certain times worn, but the rough surface is worn
nearly smooth, appearing in certain parts of a white colour, instead of
a light drab, as usual.
But the reader may ask, if certain parts of the valves are occasionally
worn smooth, and the animal works so vigorously, how is it that they
are never rasped through? This is a very natural question, and one that
I put to myself repeatedly.
I have made frequent and careful observations while the animal was
actually at work, in order to satisfy myself upon this point, and have
always perceived that the particles of softened rock fell from, and on
each side of, the large and well-developed _ligament_ that binds the
hinge, and extends to the lowest points of the valves. Moreover, this
leathery substance always seemed scraped on the surface. I cannot,
therefore, but believe that the ligament aids very materially in
rubbing off the rock, or at all events, in graduating the pressure of
the valves during the process, and that this curious organ, instead
of being worn away, may, like the callosity upon a workman's hand,
increase in toughness the more labour it is called upon to perform.[13]
[13] Mr. Clark says, 'M. Deshayes, in his comment on Pholas, in the
last edition of Lanarck, mentions the hinge as scarcely existing, and
not being _a veritable ligament_.' How different from the fact; and
I will observe, that '_if there is a genus better provided than any
other of the bivalves with ligamental appendages, it is Pholas.... The
Pholas is iron-bound as to ligament_, which in it is far more powerful
in securing the valves, than is the shell of any other group of the
acephala, of similar fragility and tenuity!'
The reason why so few specimens of the Pholades exhibit a worn shell
may be thus explained: As the animal only bores the rock in sufficient
degree to admit of its increased bulk of body, it only requires to bore
occasionally, and there may be often an interval of many months, during
which time nature may have renewed the serrated edge and rough surface
of the valves, and thus enabled the creature to renew its wondrous
operations.
We now come to a consideration of the foot, which, as many writers
aver, forms the 'sole terebrating agent.'
Although this sweeping statement is incorrect, I will freely admit that
the foot constitutes an agent second only in importance to the shell of
the animal. A casual examination of any Pholas perforation will show
that the foot could not have been the only instrument by which the
cavity was formed, from the peculiar rings that line the lower portion
of its interior. These rough appearances, I feel convinced, could be
formed by no other means than the rotatory motion of the shelly valves.
The valves, however, could not rotate and press against the surface of
the rock, were it not for the aid which the foot affords to the animal,
by its being placed firmly at the base of the hole, and thus made to
act as a powerful fulcrum.
This supposition fully accounts for the lowest extremity of the rocky
chamber being always smooth, and hollowed out into a cup-like form by
the action of the fleshy foot above alluded to.
The foot for a long time was a complete puzzle to me: I was unable to
satisfy my mind as to how it acquired its seeming extraordinary power.
The phenomenon was fully explained when I became aware of the presence
of that mysterious organ the hyaline stylet, situated _in the centre of
the foot_. The use of this springy muscle, which is, as we have shown
in the previous chapter, by naturalists erroneously considered to be
the gizzard of the animal, is, I believe, _solely to assist the Pholas
in its boring operations_.
Perhaps some of my readers would like to know how to procure a sight
of the stylet; if so, their wishes may be easily gratified. Take up a
disentombed Pholas in your hand, and with a sharp lancet or point of a
pen-knife, briskly cut a slit in the extreme end of the foot, and, if
the operation be done skilfully, the object of your search will spring
out of the incision to the extent, it may be, of a quarter of an inch.
If not, a very slight examination will discover the opal gelatinous
cylinder, which may be drawn out by means of a pair of forceps.
When extracted and held between the finger and thumb by its smaller
end, the stylet will, if struck with a certain degree of force, vibrate
rapidly to and fro for some seconds, in the same manner as a piece of
steel or whalebone would be affected, under like circumstances.[14]
[14] In the _Athenæum_ (Nos. 1632 and 1636), were kindly published two
letters from the author on the above subject, under the respective
dates January 26th, and February 28th, 1859.
So long as a Pholas exhibits only the ends of its siphons to the eyes
of a greedy crab, it is perfectly safe from attack. It is only when
the fleshy foot is unprotected that it falls a prey to some hungry
crustacean.
The toughness of the siphonal orifices is, I believe, a most important
point, for, as I shall endeavour to explain, the siphonal tubes
constitute important accessory excavating agents, to those already
enumerated.
We all know that the hole which each young Pholas makes, when first
he takes possession of his rocky home, is extremely minute,--not
larger than a small pin's head; now, it stands to reason, that if the
shell was the only terebrating agent, the opening of the cavity in
question would always remain of the same size, or, perhaps, on account
of the action of the water, a slight degree larger than its original
dimensions. Such, however, is not the case.
Here is a fragment of rock exhibiting several Pholas holes. The
aperture of one of these, which I measure, is nearly half-an-inch in
diameter, while in juxtaposition with it is situated another cavity,
measuring across the entrance less than the eighth part of an inch.
The reader will at once perceive, if the foot and shell were the sole
augurs, that as the animal descended deeper into the rock, the siphonal
tube, as it enlarged in proportion to other parts of the animal, would
have to be drawn out to an extremely fine point to fit the opening of
the tunnel. But as this is not the state of matters, the conclusion
forces itself upon us, that that portion of the orifice situated above
the shell of the animal must be enlarged by the constant extension and
retraction of the siphons, aided by currents of water acting on the
interior surface of the cavity.
This same theory will also serve to explain how it is that all Pholades
situated at the same depth in the rock, are not all of a uniform size.
I have frequently seen a piece of rock exhibit the peculiarity of two
burrows of vastly different proportions as regards breadth, being
precisely the same depth from the surface of the stone. This appears
to me equally wonderful and puzzling at first sight, as the 'boring'
question.
What age is attained by any species of the rock-borers before they
arrive at full growth, there are no means of knowing. This point,
like several others in the history of these animals, still remains a
mystery, nor is it likely soon to be cleared up. The largest specimen
of _P. crispata_ that I have seen is at present in my possession. Each
valve measures three and a half inches in length, by two inches in
breadth. Some foreign specimens of this species, and especially of _P.
dactylus_, are, however, frequently found of much larger dimensions.
On no occasion have I ever examined any Pholas excavation that had lost
its conical shape, a fact that seems to prove that the successive
stages of the boring operation must have taken place solely in
consequence of the animal not having reached its adult form.[15] For
had the shell attained its full development, and its owner continued
to labour, and rasp away the rock, the sides of the cavity at its base
would necessarily present a parallel appearance--a phenomenon which is
never witnessed.
[15] The above remark holds good, even although (_as is frequently the
case_) the animal wilfully deviates from the straight path, and bores
its tunnel in a curved form.
From this we may conclude that the depth of the perforation, which is
seldom many inches, depends entirely upon the growth of the mollusc.
When keeping specimens of the Pholas for observation, the usual plan is
to chip away the rock to the level of the valves, so that the whole of
the animal's siphonal tubes may be distinctly seen, however slightly
these organs may be extended. This plan, I found, did very well for a
time, but I was annoyed to witness, that in the course of a few months,
the siphons ceased to be either advanced or retracted,--they having
become, as it were, rudimentary.
To obviate such contingency, the writer adopted the following scheme.
To place in the tank a Pholas completely embedded in a fragment of
rock, so that nothing but the tips of its siphons, when extended to the
utmost, were visible, would not afford much pleasure to the student. I
therefore managed to saw away the rock in such a manner, as to leave a
narrow slit along the entire length of the tunnel, so as to expose the
slightest movement of the animal within. Having natural support for its
siphons, I expected that these organs would be constantly retracted and
extended; but such was not the case; at least for so long a period as I
had anticipated.
After repeated experiments, I have now discovered that whether the
siphons be protected as above described or not, they will always be
vigorously exercised if the animal be placed in shallow water, so that
its tubes when fully extended will reach the surface of the fluid.
The conclusion, from what has been stated, is, that the Pholas can
no longer be considered a weak and helpless animal. Possessed of a
rasp-like shell, a horny ligament, retractile tubes, a strong muscular
foot, and a powerful spring or stylet, it is not by any means difficult
to conceive that these agents when they are all brought into play, are
fully equal to the task of excavating the rocky chamber in which the
animal lives.
CHAPTER XVII.
The Sea-Mouse.
(APHRODITE ACULEATA.)
'For seas have ...
As well as earth, vines, roses, nettles, melons,
Mushrooms, pinks, gilliflowers, and many millions
Of other plants, more rare, more strange than these,
As very fishes living in the seas.'
[Illustration:
1 THE SEA MOUSE (_Aphrodite aculeata_)
2 THE DORIS
3 YOUNG OF THE DORIS
4 EOLIS PAPILLOSA]
XVII.
Beauteous stars also the sea contains, as numberless, though not so
brilliant in appearance as those which stud the firmament of heaven;
flowers, too, grow beneath the wave, and rival in loveliness the gems
which adorn our fields and hedge-rows. Nay, more, like the land, the
ocean owns its various grasses, its lemons, and cucumbers, its worms,
slugs, and shelly snails, its hedgehogs, its birds, its ducks and geese
(_anatidæ_), its dogs, its hares, and lastly its _mice_ (_aphroditæ_.)
The latter objects, despite their unprepossessing name, being in no
wise less interesting than those above mentioned.
The _Aphrodite aculeata_ is, perhaps, one of the most gorgeous
creatures that inhabits the seas of our British coast. Its body is
covered with a coating of short brown hairs, but as these approach the
sides of the animal, they become intermixed with long dark bristles,
the whole of which are of an iridescent character. In one respect
this creature bears no resemblance to its namesake of the land, being
extremely slow and sluggish in its movements (at least according to
our experience) when kept in confinement. Some writers, however, affirm
that the Aphrodite possesses the power, although seldom exercised, of
both running and swimming through the water with considerable speed.
In general the animal loves to tenant the slimy mud, and wherever the
writer has happened to come upon a specimen at the sea-shore, its back
has always been thickly coated with sand or dirt. The Sea-Mouse, then,
unlike the peacock, can never be deemed an emblem of haughty pride,
yet has nature in her lavish beauty endowed this humble inhabitant of
the deep with a richness of plumage, so to speak, fully equal in its
metallic brilliancy to that which decorates the tail of the strutting
bird we have mentioned. As the bristles of the Aphrodite are moved
about, tints--green, yellow, and orange, blue, purple, and scarlet--all
the hues of Iris play upon them with the changing light, and shine with
a metallic effulgence. Even if the animal, when dead, is placed in
clear water, the same varied effect is seen as often as the observer
changes his position.
Not only are the _Setæ_ worthy of notice on account of their lustrous
beauty, but also for their shape, and the important part they play in
the economy of the animal. These lance-like spines seem to be used by
the Aphrodite as weapons of defence, like the spines of the hedgehog
or porcupine. In some species they are like harpoons, each being
supplied with a double series of strong barbs.
The instruments can all be withdrawn into the body of the animal at
will, but we can easily conceive that such formidable weapons being
retracted into its flesh would not add to the creature's comfort--in
fact they would produce a deadly effect, were it not for the following
simple and beautiful contrivance.
Each spine is furnished with a double sheath composed of two blades,
between which it is lodged; these sheaths closing upon the sharp points
of the spear when the latter is drawn inwards, effectually guard the
surrounding flesh from injury.
The shape of this animal is oval, the back convex, while the under part
presents a flat and curious ribbed-like appearance. Its length varies
from three to five inches; specimens, however, are sometimes to be
procured, even on our own shores, of much larger dimensions.
CHAPTER XVIII.
Star-fishes.
(OPHIURIDAE AND ASTERIADAE.)
'As there are stars in the sky, so there are stars in the sea.'--LINK.
XVIII.
There are not a few persons still to be met with, who believe that
man and the lower animals appeared simultaneously upon the face of
the earth. Geology most forcibly proves the error of such an idea,
for although the fossilized remains of every other class of organized
beings have been discovered, human bones have nowhere been found.
This fact, though deeply interesting, is perhaps not more so than
many others which this wonderful science has unfolded. What can be
more startling to the student for instance, than the information that
for a long period, it may be thousands of years, no species of fish
whatever inhabited the primeval seas? True it is that certain creatures
occupied the shallows and depths of ocean, but these were of the lowest
type. The most conspicuous were the coral polypes, which even then as
now were ever industriously building up lasting monuments of their
existence, as the Trilobites, a group of Crustacea, and the Crinoids,
or Lily-stars.
The last-mentioned group of animals were analogous to the present tribe
of Star-fishes, and are now nearly extinct. The body of the Lily-star,
which resembled some beautiful radiate flower, was affixed to a long,
slender stalk, composed of a series of solid plates superposed upon
one another, bound together by a fleshy coat, and made to undulate
to and fro in any direction at the will of the animal. The stalk
was firmly attached to some foreign substance, and consequently the
Crinoid Star-fish, unlike its modern representative, could not rove
about in search of prey, but only capture such objects as came within
reach of its widely expanded arms. 'Scarcely a dozen kinds of these
beautiful creatures,' observes Professor Forbes, 'now live in the seas
of our globe, and individuals of these kinds are comparatively rarely
to be met with; formerly they were among the most numerous of the
ocean's inhabitants,--so numerous that the remains of their skeletons
constitute great tracts of the dry land as it now appears. For miles
and miles we may walk over the stony fragments of the Crinoidae,
fragments which were once built up in animated forms, encased in
living flesh, and obeying the will of creatures among the loveliest
of the inhabitants of the ocean. Even in their present disjointed and
petrified state, they excite the admiration not only of the naturalist,
but of the common gazer; and the name of stone lily, popularly applied
to them, indicates a popular appreciation of their beauty.' Each
wheel-like joint of the fossil Encrinite being generally perforated
in the centre, facility is thus afforded for stringing a number of
these objects together like beads, and in this form the monks of old,
according to tradition, used the broken fragments of the lily-stars as
rosaries. Hence the common appellation of St Cuthbert's Beads, to which
Sir Walter Scott alludes,--
'On a rock by Lindisfarn
St. Cuthbert sits, and toils to frame
The sea-born beads that bear his name.'
One solitary species of the Crinoid Star-fishes has of late years been
found to flourish in our own seas; it is, however, affixed to a stalk
(pedunculated) only in the early periods of its existence.
When first discovered by Mr. Thompson in its infant state, the
_Pentacrinus Europæus_ was believed to be a distinct animal. It was
taken attached to the stems of zoophytes of different orders, and
measured about three-fourths of an inch in height. In form it resembled
a minute comatula mounted on the stalk of a Pentacrinus. Subsequent
research has proved that the little stranger was merely the young state
of the feather star _Comatula rosacea_, and that although for a certain
period attached to a slender waving stem, the Pentacrinus, when arrived
at a certain stage of development, feels fully able to start life on
its own accord, and hence takes opportunity to break off its early
ties, and become a free animal, dependent upon its own exertions for
subsistence.
It is no uncommon thing, as a late writer forcibly remarks, in the
inferior classes of the animal kingdom, to find animals permanently
attached from the period of their birth, and during all their
existence. Familiar examples of this occur in the oyster, and various
other bivalve shell-fish, as well as in numerous compound zoophytes. We
likewise meet with races which are free and locomotive in their first
stages, and afterwards become permanently fixed; but an animal growing
for a period in the similitude of a flower on a stem, and then dropping
from its pedicle, and becoming during the remainder of its life free
and peripatetic, is not only new, but without any parellel in the whole
range of the organized creation.
The Comatula, or as it is commonly called, the Rosy Feather-star, is
allowed to be without exception the most lively of all the star-fishes.
Its movements in swimming are said to resemble exactly the alternating
strokes given by the medusa to the liquid element, and have the same
effect, causing the animal to raise itself from the bottom, and to
advance back foremost even more rapidly than the medusa. It has ten
very slender rays with numbers of long beards on the sides. The body,
which is of a deep rose colour, is small and surrounded with ten little
filiform rays. The extremities of these organs are shaped like claws,
by means of which the animal attaches itself to various kinds of
sea-weed, and other submarine objects.
The adult Comatula generally measures about five inches across its
fully expanded rays.
Before treating of what are termed the _true_ Star-fishes, we require
to dwell briefly upon an intermediate family named by Professor Forbes
the _Ophiuridæ_, 'from the long serpent or worm-like arms, which are
appended to their round, depressed, urchin like bodies.... They hold
the same relation to the Crinoidea that the true Star-fishes hold to
the Sea-Urchins. They are spinigrade animals, and have no true suckers
by which to walk, their progression being effected (and with great
facility) by means of five long flexible-jointed processes placed at
regular distances around their body, and furnished with spines on the
sides and membraneous tentacula. These processes are very different
from the arms of the true Star-fishes, which are lobes of the animal's
body, whereas the arms of the Ophiuridæ are super-added to the body,
and there is no excavation in them for any longation of the digestive
organs.'[16]
[16] British Star-fishes.
The British Ophiuridæ are now classed under two genera; of the Ophiuræ,
or Sand-stars only two species (_O. texturata_ and _O. albida_) are
found on our shores; and the Ophicomæ, or Brittle-stars, of which there
are ten.
An extraordinary feature, characteristic of all the above-mentioned
animals, is the great tendency which they have to mutilate themselves,
and throw their limbs about in fragments on the slightest provocation.
If a specimen be handled, a certain number of fragments will assuredly
be cast off. If the rays become entangled in sea-weed, or even if the
water in which the animal resides happens to become impure, the same
disastrous result follows, until nothing but the little circular disc
remains. As a set off against this weakness, both the Ophiuræ and the
Brittle-stars possess reproductive powers of a high order. Hence it not
unfrequently happens that if each and all the rays of a specimen be
rejected, the animal will live on, and eventually, perhaps, become a
complete and perfect star-fish.
The best means of preserving an Ophiura is to let the devoted animal
remain for a time expanded in sea-water, then with a small pair of
forceps lift it carefully up, and plump it into a bath of cold 'fresh'
water, letting it lie there for about an hour. The animal speedily
dies, as if poisoned, in the fresh liquid, in a state of rigid
expansion. Some writers recommend that, at this stage, the specimen
should be dipped for a moment into boiling water, and then dried in a
current of air; but I have never been able to detect any great benefit
arising from the adoption of the process.
When examining any of the Brittle-stars, I have always found it an
excellent plan to raise them up by aid of the forceps applied to the
disc. By this means a specimen may be moved about without any fear
of mutilation; whereas if the fingers be used as forceps, an unhappy
result will assuredly follow.
The _Ophiocoma rosula_, figured on Plate 9, will serve to convey to
the reader a general idea of this class of animals. Its popular title
is the Common Brittle-star, indicative of the inherent fragility of the
species, as also of their prevalent appearance at the sea-shore; but,
though so exceedingly 'common,' we must at the same time in justice
add, that the _O. rosula_ exceeds in beauty many other species which
are rare, and consequently more highly prized by the collector.
It is very abundant on all parts of the British coast, and is often
found in clusters upon the stems of _L. digitata_, and as frequently
upon the under side of boulders. In dredging, the Brittle-star is an
unfailing prize. It is a marvellous sight when the scrapings of the
ocean bed are spread out upon the dredging-board for examination,
to see hundreds of these singularly delicate creatures twisting and
twining about in all directions,--over each other's bodies, through the
weed, sand, shells, and mud, and strewing fragments of their snake-like
arms upon every surrounding object.
At the mere mention of 'Star-fishes,' the most uninitiated reader will
at once realize in his mind's eye a tolerably correct notion of the
form of these curious productions of the marine animal kingdom, even
although he had never seen a living or dead specimen.
The body of the animal is divided into rays, like the pictured form of
one of the heavenly stars, and the fancied resemblance is most apparent
in the Asteridæ, or true Star-fishes, of which we are now about to
speak.
This wonderful race of animals, for their beauty of colour, elegance
of shape, and peculiarity of structure, possess a great degree of
interest, not only to the naturalist, but also to the casual observer
by the sea-side.
There are fourteen British species of Asteriadæ, which are arranged
under four families, namely--the Urasteriæ, the Solasteriæ, the
Gonasteriæ, and the Asteriæ. This group contains no less than eight
generic types, clearly distinguished from each other by certain
characters, 'derived from the outline of the body, the number of rows
of suckers in the avenues, and the structure and arrangement of the
spines covering the surface and bordering the avenues.'
There are four species of Star-fishes belonging to the genus Uraster,
the most common of which is the _Uraster rubens_, or Common Cross-fish.
No person in the habit of visiting the sea-shore can be unfamiliar with
the likeness of this creature, which is generally seen lying wedged
in some rocky crevice, or among the Fuci, there patiently waiting the
return of the tide.
At such a time, the Devil's-hand (as the Irish people term it), does
not appear by any means attractive. If placed in water, however, its
appearance becomes wonderfully improved.
Here is a small specimen, just brought from the sea-shore at
Cockburnspath (a most romantic and delightful locality, situated on
the coast of Berwickshire). It is neatly wrapped up in a mantle of
sea-weed. Freed of its verdant envelope, I deposit the youthful Rubens
upon his back--'willy-nilly'--in a tumbler partly filled with clear
sea-water, and then proceed to watch its movements through a magnifier.
At a glance we perceive that each of its five rays is grooved on its
lower surface, and filled with minute perforations, through which is
gradually protruded a multitude of fleshy suckers, knobbed at the end.
It is by aid of these organs that the animal grasps its food, and
changes its position, as we shall presently see. One of the rays is now
slowly lifted up and moved about in various directions, while from its
extreme point the suckers are extended to the utmost limit. No sooner
do they touch the side of the vessel than they are firmly fixed and
contracted. A _point d'appui_ being thus gained, the animal is enabled
by degrees to draw its body round, so as to get another regiment of
suckers into play, and, by such plan of operations being repeated,
the animal is eventually enabled to 'right itself,' and crawl up the
polished surface of the glass.
Generally, when the Star-fish is disturbed, or placed on a dry piece
of stone, the suckers are withdrawn into the body, leaving no signs
of their previous existence except a series of minute tubercles. In
fact, the Asterias, although enabled to adhere with great tenacity to
any foreign object when immersed in water, possesses but little power
to retain its hold if the fluid be removed. Hence the young zoologist,
keeping this peculiarity in mind, should not too hurriedly return a
verdict of 'Found dead,' when he meets with a helpless specimen upon
the beach, for in all likelihood, were the creature to be laid for a
few minutes in a rock-pool, it would soon exhibit signs of returning
animation.
A simpler, though not so sure a test for ascertaining whether a
Star-fish be living or not, is to handle the specimen. If it feels soft
and flabby, it is dead; but if tolerably firm to the touch, it may be
'recalled to life,' by the means pointed out.
It may not be out of place to chronicle here a singular circumstance
which the writer has often verified in connection with the true
Star-fishes. It is this. When any captured specimens have been placed
in confinement, no matter how large or small such might be, they never
moved through the liquid element with a tithe of the rapidity that I
well knew they were capable of. At the sea-side, I have seen a specimen
of the Cross-fish glide through the water so nimbly, yet withal so
gracefully, that I have felt inclined to rank natation among the few
other acomplishments of which the species can boast.
The _Uraster rubens_ is also popularly known as 'Five Fingers.' For
ages past it has been subject to the bitter denunciation of fishermen
and others, for the injury which it is said to inflict upon oysters.
At one time, according to Bishop Spratt, the Admiralty Court laid
penalties upon those engaged in the oyster-fishing who did not
tread under their feet, or throw upon the shore, a fish they call a
Five-Finger, resembling a spur-rowel, because that fish gets into the
oysters when they gape, and sucks them out. Poets have also endeavoured
to perpetuate the vulgar opinion:--
'The prickly Star-fish creeps with fell deceit,
To force the Oyster from his close retreat,
Whose gaping lids their widened void display;
The watchful Star thrusts in a pointed ray--
Of all its treasures robs the rifled case,
And empty shells the sandy hillock grace.'
Even yet the oyster fishermen at certain localities wreak all
possible vengeance upon the 'submarine Dando's,' for their supposed
gourmandizing propensities. I say _supposed_, for although so
many naturalists have studied the question, it is not, up to the
present time, satisfactorily settled. Some deny the alleged tendency
altogether, while less sceptical observers are unable to understand
the mode in which the Star-fish could injure an animal apparently so
capable of self-defence as the oyster. According to certain authors,
the Star-fish encircles the oyster with its five fingers, and by some
clever process of suction destroys the unfortunate mollusc. Others,
again, maintain that the first step of the attack is the injection
of some marine chloroform between the shells of the oyster, and that
during the insensibility that follows, the Star-fish effects an
entrance.
As this is an interesting subject, perhaps the reader would like to
have the exact words which are used by two celebrated naturalists, one
of whom attempts to vindicate the character of the Asteridæ, the other
to blacken it.
Sir John Dalyell--a high authority upon all matters of marine
zoology--shrewdly remarks: 'I have not heard it suggested that the
Star-fish possesses any kind of solvent compelling the bivalves
to sunder. Neither can its hostility be very deadly to the larger
univalves, from the distance to which they are enabled to retreat
within their portable dwellings. Their general habits are, to force the
shells of smaller bivalves asunder, and to devour the contents; they
likewise consume the substance of ordinary fishes entire; nevertheless,
as far as I am yet aware, their destruction of oysters is destitute of
evidence. The Star-fish sometimes shows an eversion of stomach, or of
some membrane of it. Whether this may be the means of affecting their
prey, merits investigation.'
Professor Jones, who affirms that in the latter suggestion Sir J.
Dalyell has nearly hit upon the true solution of the problem, thus
gives what _he_ considers to be the correct mode of procedure on the
part of the Star-fish: 'Grasping its shell-clad prey between its rays,
and firmly fixing it by means of its prehensile suckers, it proceeds
deliberately to turn its stomach inside out, embracing in its ample
folds the helpless bivalve, and perhaps at the same time instilling
some torpifying fluid, for the shells of the poor victim seized soon
open, and it then becomes an easy prey.'
Now, many fishermen with whom I have conversed hold the same opinion as
Bishop Spratt, and believe that when the oyster is gaping the Star-fish
insinuates a finger, and hastily scrapes out the delicious mouthful;
nay, further maintain that the Star-fish is far from being successful
at all times, very often, especially when there has only been one ray
inserted, the frightened oyster grasps it with all his might, and
obliges his discomfited opponent to retire minus a limb.
If the writer might venture to suggest an opinion, he would express
his belief that the following is the correct account of the state of
matters. He believes with the fishermen that frequently the star-fish
begins his attack by inserting an arm, but he does not believe that the
oyster under such circumstances escapes with life. Let us suppose the
star-fish to have succeeded in insidiously introducing a ray within the
shell of the apathetic oyster, and that the oyster immediately resented
such intrusion by closing his shell with all the force he can exert.
The opposite argument at this stage is, that the intruder is obliged
from _pain_ to abandon his hold, and even pay for his audacity by the
forfeit of a limb. But against this we advance the notorious fact, that
the star-fish, like so many marine creatures of a similar organization,
is remarkably indifferent to pain. I therefore believe the true
explanation to be, that the oyster being unable to sustain such
continued muscular exertion for nearly so long a time as the star-fish
can tolerate the pressure upon its ray, the latter is consequently, in
the long run, successful.
The number of rays in the several genera of the true Star-fishes is
extremely various. In the genus _Uraster_, as we have seen, five is
the predominant number. If we turn to the two species which comprise
the genus _Cribella_, we still find the quintuple arrangement adhered
to. In _Solaster endeca_, on the contrary, the rays vary from nine
to eleven, and even reach as high as twelve or fifteen in _Solaster
papposa_.
In the genus _Palmipes_ we have the pentagonal form, it is true, but
the space between each ray is filled up, so as to resemble the webbed
foot of a bird, hence the popular title of this solitary species,
'The Bird's-foot Sea-star.' 'It is the flattest of all its class, and
when alive it is flexible like a piece of leather.' Passing by the
'Cushion-stars' (which have five _angles_--it seems a misnomer to call
them rays), which connect the true Star-fishes with the Sea-Urchins,
we come lastly to the 'Lingthorn,' _Luidia fragillisima_, with its
seven rays. This is the animal of which Professor Forbes discourses so
pleasantly about its winking derisively at his despairing endeavours
to preserve even a small portion of what at that time was his maiden
specimen. The Luidia is even more brittle--more regardless of its
wholeness, than the _Ophiuræ_, which renders the capture of a perfect
specimen a most difficult task.
CHAPTER XIX.
Sea-Urchins (Sea-Hedgehogs).
'Truly the skill of the Great Architect of Nature is not less displayed
in the construction of the Sea-Urchin than in the building up of a
world.'--P. FORBES.
[Illustration:
1 THE APLYSIA or SEA-HARE
2 PURPLE-TIPPED SEA-URCHIN
3 Spine of PURPLE-TIPPED SEA-URCHIN
4, 5 Suckers of PURPLE-TIPPED SEA-URCHIN
6 COMMON SUN-STAR]
XIX.
Sea-Urchins are frequently taken in dredging. Several common species,
usually of a small size, are often found among the rocks situated
between tide marks.
Into the aquarium no specimens larger than from one to two inches in
diameter should be introduced, and even these require to be closely
watched, for if afflicted with a fatal illness, I know of no animal
whose remains sooner taint the water. Almost before life is extinct,
the Urchin throws out a light-coloured nauseous fluid, that speedily
poisons the surrounding water, and, of course, causes the destruction
of any inhabitants of the tank who may neither have the sense nor
opportunity to inhale copious draughts of fresh air. As a rule, if the
suckers are motionless, or if on touching the animal it is found not to
be adherent to any object, transfer it at once to your 'infirmary' for
further observation.
I have always found small specimens to be much more lively and
walkative, (if I may be allowed the expression) than their more
corpulent brethren.
The inflexible, mail-like crust, or shell, as it is commonly called,
of the Echinus is perhaps one of the most marvellous objects on which
the eye can rest. Although at first sight it appears to be a solid
calcareous box, it is in reality composed of several hundred pentagonal
plates,[17] of various sizes, so closely dove-tailed together that
their marks of junction are scarcely perceptible. Upon a superficial
examination we are apt (most erroneously) to consider this wonderful
piece of work to be more elaborate than the wants of the animal demand.
The fact of the Lobster or Crab throwing off its entire shell at
certain seasons, to admit of the increased growth of the animal is a
truly marvellous phenomenon, still, it would more excite our wonder
were we to find that, instead of being cast away at all, the hard,
inelastic envelope which surrounds the bodies of crustaceans was made
to swell or expand proportionately with the soft parts of the animal!
Now, the mosaic-like shell of the Sea-Urchin, though built up, as
before stated, of several hundred pieces, is by a beautiful process
slowly and imperceptibly enlarged correspondingly with the growth of
the animal.
[17] In a specimen that I examined, and then carefully took to pieces,
there were exactly 1780 plates.
The gradual enlargement of the Echinus shell takes place in the
following manner:--
Over the entire surface of the globular shell, spines, and joints of
the living Urchin, there exists a delicate membrane that insinuates
itself between the pentagonal plates above mentioned, and continually
deposits around the edges a certain portion of calcareous matter
(carbonate of lime). The same process being also carried on by the
fleshy covering that surrounds the spines, &c., it must be evident that
so long as the vital power of the animal exists, each plate and spine,
still keeping to its original form, must be daily and hourly augmented
in size until the Sea-Egg has attained its full and mature dimensions.
As to how the spines retain their relative position in each plate, as
the latter gradually becomes enlarged, I cannot positively state; but
may be permitted to mention, that, judging from carefully prepared
sections of the plates when submitted to the microscope, each spine
appeared to my eye to be by some singular process urged along in a kind
of groove to its proper place.
The hedgehog-like spines that surround the globose body of the
Sea-Urchin are all moveable at the will of the animal,--each prickle
being connected by a ball-and-socket joint to a pearly tubercle, which
acts as the 'socket' on which the 'ball' of the spine revolves. If
the spine be removed, a comparatively smooth surface will be left, on
which are various sized tubercles systematically arranged. Situated at
regular intervals between the tubercles are ten broad bands, disposed
in pairs, and containing many hundreds of very minute perforations, or
ambulacral orifices, as they are generally termed by naturalists.
Through these apertures issue numerous sucker-like feet, closely
resembling those of the Star-fish, but endowed with far greater powers
of contraction and extension.
The number of suckers is very great. In an Urchin measuring exactly
three inches in diameter, by aid of a hand lens, I counted no less than
3300 pores in the ten avenues. Now, these pores are always situated in
pairs, and as each sucker occupies a pair of pores, it will give 1650
as the total amount of suckers.
There is no doubt that it is almost entirely by means of these curious
organs that the Sea-Urchin is enabled to move about from place to
place, although no less an authority than Professor Agassiz asserts
to the contrary. 'How, in fact,' says this author, 'could these small
tentacula, situated as they generally are in that part of the body
which is never brought into contact with the ground when the animal
moves, and overhung by calcareous solid spines--how, I ask, could
these flexible tubes be used as organs of motion? It is an undeniable
fact, and I have often observed it myself, that _it is with their
spines the Echini move themselves, seize their_ _prey, and bring it
to their mouths_ by turning the rays of their lower edge in different
directions. But the correction of an error respecting the functions
of the ambulacral tubes does not solve the problem relating to their
nature and use. This problem we are yet unable to solve, as we know
nothing more respecting them than that they are connected with the
aquiferous system.'
Many other writers, among whom is Professor Forbes (from whose work
on Star-fishes I have transferred the foregoing extract), assert, in
opposition to the great Swiss naturalist, that the Echinidæ move by
the joint action of their suckers and spines. 'The argument,' says the
great British naturalist, 'against the suckers being organs of motion,
founded on their position above as well as below, would equally apply
to the spines, to which organs Professor Agassiz has attributed all
progressive powers in these animals.'
The fact is now so well established, that it is scarcely necessary
for the writer to state, that from personal observation he can fully
confirm the evidence of Professor Forbes relative to the functions
of the suckers of the Sea-Urchins. But although that talented author
entertained no doubt as to the organs in question being powerful
locomotive agents, he evidently seems to have felt himself unable to
suggest any purpose they could possibly serve when situated on the back
or upper part of the animal.
My own experience incontestibly proves that the suckers in question
are used for precisely the same purpose as those situated in any
other part of the body. I am enabled to state, from having repeatedly
witnessed the phenomenon, that _the Echinus can walk about with equal
facility while lying on its back as in its more natural position_. The
advantage of this power to the animal under certain circumstances will
be apparent upon a little reflection.
With regard to the spines, I fancy their purpose is almost solely to
assist the Urchin to burrow in the sand, and to protect it from the
attacks of its enemies. It may be, however, that at particular times
they serve as aids to locomotion, but that their assistance can be, and
is, often dispensed with entirely by the animal, I can most positively
assert.
My experiments were always conducted in glass vases, up the smooth,
polished sides of which my specimens frequently advanced. Upon reaching
the surface of the water, I have seen an Urchin roll completely round
and move along on its back, then after a time change its position, and
travel round the circumference of the vessel _while attached by its
side_, the body of the animal being sometimes inverted.
At such times as these it must be quite evident that the spines would
be totally useless, and that by the suckers alone did the animal
perform its interesting movements.
According to a certain writer, there are some foreign species of the
Echini remarkable for possessing spines, which act both as offensive
and defensive weapons. 'On one occasion' (this writer says) 'when
searching for a fish in the crevice of a coral rock, I felt a severe
pain in my hand, and upon withdrawing it, found my fingers covered
with slender spines, evidently those of the Echinus, of a grey colour,
elegantly banded with black.
'They projected from my fingers like well-planted arrows from a target,
and their points being barbed could not be removed, but remained
for some weeks imbedded as black specks in the skin. Its concealed
situation did not permit me to examine this particular Echinus. In some
experiments I approached the spines with so much caution, that had they
been the most finely pointed needles in a fixed state no injury could
have been received from them, yet their points were always stuck into
my hand rapidly and severely.'
In addition to those above described, the Sea-Urchin is provided with
other organs, in shape somewhat resembling minute pincers, supported on
fleshy stems, which always keep up an incessant motion when the animal
is in a healthy condition. They are scattered in great numbers over
the surface of the body, among the spines, and around the mouth of the
Urchin.
The use of these singular objects--by naturalists termed
Pedicellariæ--is totally unknown. Some writers think they are an
integral part of the Echinus, others describe them as distinct and
parasitic animals. There is good reason to believe that the former will
eventually be proved to be the correct explanation of the matter.
Its masticatory apparatus is not the least wonderful portion of the
Sea-Urchin. The teeth, five in number, which may frequently be seen
protruding from the mouth, are of extreme hardness, and of seemingly
disproportionate length. They are not fixed in sockets as ours are,
or they would be speedily worn away by their action on the shelled
mollusca upon which the animal feeds, but fresh substance is added
to each tooth as fast as it is worn away by use, as in the case of
many gnawing animals. 'In order to allow of such an arrangement, as
well as to provide for the movements of the teeth, jaws are provided,
which are situated in the interior of the shell, and these jaws, from
their great complexity and unique structure, form perhaps the most
admirable masticating instrument met with in the animal kingdom. The
entire apparatus removed from the shell consists of the following
parts. There are five long teeth, each of which is enclosed in a
triangular bony piece, that for the sake of brevity we will call jaws.
The five jaws are united together by various muscles, so as to form a
pentagonal pyramid, having its apex in contact with the oval orifice
of the shell, while its base is connected with several bony levers by
means of numerous muscles provided for the movements of the whole.
When the five jaws are fixed together in their natural position, they
form a five-sided conical mass, aptly enough compared by Aristotle
to a lantern, and not unfrequently described by modern writers under
the name of "the lantern of Aristotle." The whole of this complicated
machinery is suspended by muscles from a frame-work fixed in the
interior of the shell, and may often be picked up upon the beach, or
still better exposed _in situ_ in a dead Echinus, by those who would
examine closely this wonderful piece of mechanism.'[18]
[18] The 'Aquarian Naturalist,' p. 224.
I have made two careful drawings of the jaws and teeth of the Echinus.
No. 1 represents, as it were, the 'elevation' of the pentagonal pyramid
above described, while No. 2 constitutes the 'plan' of the same object.
The _Echinus sphæra_, or common Egg-Urchin, may often be seen forming
a curious ornament in the drawing-rooms of the "West End," and also in
the dwellings of the poorer classes, who, according to some authors,
boil it like eggs, and so eat it. Hence its popular title. Among the
ancients the Echinidæ were accounted a favourite dish. 'They were
dressed with vinegar, honied wine or mead, parsley and mint. They were
the first dish in the famous supper of Lentulus when he was made Flamen
Martialis. By some of the concomitant dishes they seemed designed as a
whet for the second course to the holy personages, priests and vestals,
invited on the occasion.'
The illustration on Plate 10 was drawn from a living specimen, and
gives a somewhat unusual representation of a Sea-Urchin. In general the
spines alone are shown, but I have endeavoured to give the uninitiated
reader some faint notion of the appearance which the _suckers_ present
when extended from the surface of the shell.
The young Urchin sat very quietly while I was engaged in taking his
portrait, but continually extended crowds of his slender tubular legs
in all directions, as above indicated, much to my gratification and
apparently to his own.
In preparing a Sea-Urchin for a chimney ornament, the most important
point is to remove the spines so as to let the tubercles remain entire.
In performing this operation some little experience is necessary.
Several times I attempted the process by aid of a pen-knife and a pair
of pliers, but not with a satisfactory result. Having mentioned my
difficulty to a friend, he laughingly asked me if I had ever heard of a
certain pilgrim who, for some peccadillo he had committed, was doomed
to perform penance by walking to Loretto's shrine with peas in his
shoes? Of course I was acquainted with the story, but could not see
what it had to do with Sea-Urchins, and told my brother naturalist so.
Still smiling, he said, 'Do you remember the relief that was said to be
afforded to the humorous rascal, both mentally and bodily, by _boiling
his peas_?' Yes. 'Well, then,' was the reply, 'do you boil your
Sea-Eggs, and you will find your troubles speedily cease.' I did as I
was directed, and found the advice of great service; for, after being
an hour or two in the 'pot,' the spines of the Urchin may be totally
rubbed off by aid of a nail brush, or some such instrument. Moreover,
the colour of the shell is improved, and the dental apparatus may be
drawn out entire, with the greatest ease.
I may here take opportunity to mention, that the student who may think
proper to act upon the hint above given, should not boil the Urchin too
long, or the fleshy parts will become dissolved, and the entire shell
fall into a multitude of fragments.
This unfortunate result actually happened on one occasion to a genial,
clever friend of mine, much to his chagrin and my malicious delight.
There are several other species of Sea-Urchins whose forms are
tolerably well distinguished by their popular appellations. Thus we
have the 'Silky Spined Urchin;' the 'Green Pea-Urchin,'--the latter
is the commonest and prettiest of all its kindred, its back being
covered with a kind of powdery green, as is seen on the elytra of
many beetles; the 'Cake-Urchin,' which from its flattened form may be
regarded as a link between the Sea-Urchins and the true Star-fishes;
the 'Purple Heart-Urchin,' and the pretty 'Rosy Heart-Urchin,'
appropriately named from the brilliant crimson hue that its body
presents during life.
CHAPTER XX.
Sea-Cucumbers.
(HOLOTHURIADÆ.)
XX.
There is a very singular group of animals, the _Holothuriadæ_, that
claims a passing notice, from their near relation in structural
formation to the Sea-Urchins, although externally they also exhibit
a certain resemblance to the _Annelides_. They are commonly termed
Sea-Cucumbers, from the fancied likeness which they bear, both in shape
and colour, to their namesakes of the vegetable kingdom.
A Holothuria is very unattractive in appearance when lying listless
upon the sea-beach, but if a small specimen be transferred to the
aquarium, it exhibits features of a very singular and interesting
character. When about to change its position, the head, hitherto
concealed, is protruded and expanded, until it assumes the form of a
beautiful flower.
The animal moves principally by aid of sucker-like feet, similar in
form to those of the Asteriadæ, or Sea-Urchins. In most species, the
body is divided longitudinally into five rows of suckers. In some,
however, these organs are scattered over the entire surface, while in
the small Sea-Cucumber (_Psolus phantapus_), they are arranged in three
rows upon a soft, oblong, flat disc, situated beneath the body of the
animal, like the foot of a gasteropod mollusc.
Of one genus--the Trepang--many species are eaten by the omnivorous
inhabitants of the Celestial Empire, by whom it is employed in the
preparation of 'nutritious soups, in common with an esculent sea-weed,
shark's fins, edible birds' nests, and other materials affording much
jelly.' The intestines, which are generally found to be filled with
coral, and solid masses of madreporic rock, are extracted, and the
animal then boiled in sea-water and dried in smoke.
Nothing can possibly be less enticing than the black and shrivelled
carcases of these defunct gasteropods, as they are seen spread out and
exposed for sale in the China markets. There are many varieties of
Trepang, some being held in higher esteem than others,--hence the great
difference which exists in the price of the article. The lowest quality
being ten dollars, and the highest fifty dollars, per pecul of 133 lbs.
The following are titles by which a few of the Holothuriæ are known in
China:--
Great Black-Stone Trepang;
Peach-blossom Trepang;
Great White-Stone Trepang;
The Bald Trepang;
The Scarlet Trepang;
Great Clear-Ball Trepang;
The Middle Ash-Bald Trepang, &c., &c.
The illustration on Plate 11 gives a good idea of the typical form
of the Holothuriadæ. It represents a species of the genus Cucumaria,
_C. communis_, or common Sea-Cucumber. Its length is from four to
eight inches; but, like all its kindred, it possesses the power of
considerably extending or contracting its body at will. The Tentacula
are ten in number, pinnate and plumose, stalked and rather large. The
body is five-sided, with numerous suckers on the angles, but more on
the sides, which are papilose. The colour is yellow, or brownish-white,
although specimens found on the Irish coast exhibit a purplish hue.
This, the most common species of its genus, is an inhabitant of
deep water, and is therefore most frequently taken with the dredge.
Occasionally, specimens may be found after violent storms stranded on
various parts of the shores of the United Kingdom.
The Sea-Cucumbers possess the singular power of disembowelling
themselves upon the slightest provocation, and also of throwing off
their Tentacula entire. There is one species, indeed, that exhibits
a still more wonderful phenomenon. At certain times members of this
species will divide their body into a number of parts, each of which
will in due course become a new and completely-formed animal. After
this the reader will be prepared to learn, that to build up a new
inside, or create a new set of branchiæ, is to a Holothuria a very
trifling and insignificant task.
CHAPTER XXI.
The Aplysia, or Sea-Hare.
'The origin and the source of the smallest portion of the universe
overpowers our comprehension. How little can the acutest senses, the
profoundest judgment, the widest view, embrace! It is as nothing; it is
as less than nothing. We are capable of doing no more than surveying
the edifice and adoring the Architect.'
SIR J. DALYELL.
XXI.
At several parts of the Scottish coast, and especially at North
Berwick, may be found specimens of that curious gasteropod named the
Aplysia, or Sea-Hare, the _Lepus marinus_ of the ancients.
On visiting North Berwick during summer, I have been astonished to
discover, in almost every pool, from two to twenty of these creatures.
At rest, the Aplysia is not by any means inviting, but when in motion,
elevating and depressing the fleshy mantle that covers over the fringed
and lobed branchiæ, its appearance is exceedingly graceful.
Striding across a pool on the look-out for some Gobies, whose forms
darting beneath a large stone had not escaped my glance, I perceived
the water in the rocky basin gradually lose its crystal brightness, and
become changed to crimson. The Gobies were therefore allowed to rest
in peace, while I proceeded to investigate a phenomenon that, at the
moment, seemed somewhat singular.
A kind friend and brother zoologist, who happened to be near, called
attention to the fact that the crimson stream flowed thickest near
where my foot rested.
On closely examining the spot pointed out, and turning over some fronds
of Dulse, we came upon a small fleshy ball of a dark brown colour,
from which there still issued a fluid of vivid crimson hue. Having
placed this strange object in a bottle, I soon pronounced it to be an
Aplysia, with whose full-length portrait, as represented in books, I
had previously been made acquainted.
The power which this animal possesses, under irritation, of spurting
out a peculiar secretion, I also remembered to have seen mentioned by
several writers on natural history.
Although generally believed to be gentle and perfectly harmless, yet,
as Professor Forbes observes, few molluscs have had a worse character
than the Aplysiæ. From very ancient times they have been regarded with
horror and suspicion; and many writers on natural history, conversant
with them only through the silly stories of ignorant fishermen,
have combined to hold them up as objects of detestation. To touch
them, according to European prejudices, was sufficient to generate
disease in the foolhardy experimenter; while Asiatics, reversing
the consequences, maintained, perhaps with greater truth, that they
met with instantaneous death when handled by man. Physicians wrote
treatises on the effects of their poison, and discussed the remedies
best adapted to neutralize it. Conspirators brewed nauseous beverages
from their slimy bodies, and administered the potion confident of its
deadly powers. Every nation in the world on whose shores the poor
Sea-Hares crawled, accorded to them the attributes of ferocity and
malignant virulence, although there never appears to have been the
slightest foundation for a belief in their crimes.
A specimen of the Aplysia that I had in my tank deposited a stringy
coil of spawn, which closely resembled that of the Eolis, with the
exception that the eggs, instead of being white, were of a reddish
tint.
CHAPTER XXII.
Serpulæ and Sabellæ.
[Illustration:
1, 2 SEA-URCHIN'S TEETH (Two illustrations.)
3 COMMON SEA CUCUMBER
4 COMMON RAZOR-SHELL
5 COMMON SERPULÆ, attached to a piece of stone.]
XXII.
With the exception of the Balani (Acorn-Barnacles), perhaps the most
common objects to be met with at the sea-shore are the Serpulæ.
Scarcely a rock, or shell, or bit of old china, or piece of wood, or
rusty nail, lying near low-water mark, but is encrusted with colonies
of these animals. I have a small twig of a tree by me, so thickly
coated with Serpulæ as to obscure all signs of its ligneous character,
except at each end. A shell also exhibits the same phenomenon, and
well-nigh defies the most skilful observer to define its original form
with any degree of certainty.
The shelly tubes of these animals are built in the form of serpents,
or twisted funnels, of a milk-white colour. Although so extremely
hard, these tubes are formed solely by an exudation from the body
of the animal--a simple marine worm. Unlike its erratic friend, the
earth-worm, the Serpula is sedentary in its habits, and at no time does
it ever leave its dwelling.
The delicate, but brilliant feathery plume--the only portion of the
animal ever visible--constitutes the principal mechanism by means of
which the Serpula constructs its calcareous tube.
A most wonderful instance of how mighty are the works which these
insignificant creatures form when congregated together in vast numbers,
and how useful such labours may sometimes be to mankind, is narrated by
Dr. Darwin in his 'Voyage of the Beagle.'
Being delayed by adverse winds, this gentleman made a stay at
Pernambuco, a large city on the coast of Brazil, and the most curious
object that he saw there was the reef that formed the harbour. 'I
doubt,' to use his own words, 'whether in the whole world any other
natural structure has so artificial an appearance. It runs for a length
of several miles in an absolutely straight line, and parallel to, and
not far distant from the shore. It varies in width from thirty to
sixty yards, and its surface is level and smooth; it is composed of
obscurely stratified hard sandstone. At high water the waves break over
it; at low water its summit is left dry, and it might then be mistaken
for a breakwater erected by Cyclopean workmen. On this coast the
currents of the sea tend to throw up in front of the land long spits
and bars of loose sand, and on one of these the town of Pernambuco
stands. In former times a long spit of this nature seems to have become
consolidated by the percolation of calcareous matter, and afterwards
to have been gradually upheaved, the outer and loose parts during the
process having been worn away by the action of the sea, and the solid
nucleus left as we now see it. Although night and day the waves of
the open Atlantic, turbid with sediment, are driven against the steep
outside edges of this wall of stone, yet the oldest pilots know of no
tradition of any change in its appearance. This durability is by far
the most curious fact in its history; _it is due to a tough layer, a
few inches thick, of calcareous matter, wholly formed by the successive
growth and death of the small shells of Serpulæ, together with some
few Barnacles_, &c. These insignificant organic beings, especially
the Serpulæ, have done good service to the people of Pernambuco, for
without their protective aid the bar of sandstone would inevitably have
been long ago worn away, and without the bar there would have been no
harbour,'
Nothing whatever appears to be known relative to the mode of
reproduction of these Annelids. I have paid much attention to the
subject, but as yet have not gained any positive information regarding
it. The only fact which I consider worthy of being chronicled is the
following: On one occasion, when quite a novice in Marine Zoology,
while observing a beautiful group of Serpulæ seated on a stone, I saw
issuing from out one of the tubes a kind of very fine dust, of a rich
crimson hue, which continued to arise for nearly an hour in spite of
repeated efforts to disperse it by aid of a camel-hair pencil. At first
I believed the 'dust' to be the 'remains' of a deceased serpula, but
afterwards found that such was not the case, the annelid being alive
and healthy. Never having seen the phenomenon since, it has been a
great source of regret to me that I did not endeavour to discover what
the dust was composed of; but have little doubt that the microscope
would have shown it to be, in reality, the ova of the Serpula.
Another class of Annelidans, termed Sabellæ, like the Serpulæ, also
build habitations for themselves, but not of the same materials.
Instead of being white, the tubes of the first mentioned animals are
brown in colour, and composed of minute granules of sand, or small
shells, and lined internally with a gelatinous substance exuded from
the body of the worm. On the interior of the oyster and other shells,
and even in univalves occupied by the Lobster Crab, various tubes of
Sabellæ may often be seen. They are, however, generally discovered
congregated together, forming a kind of honeycomb mass in the fissures
of rocks, or against the sides of rock-pools, or on the surface of
small stones, &c.
A mass of Sabellæ tubes forms by no means an inappropriate or
unpleasant object for the tank, as the animals are hardy, and will
live for many months if the water be kept pure. Moreover, while in
confinement, they do not live in luxurious indolence, but ever seem
to be busy in the exercise of their architectural propensities, making
alterations, repairing damages, or otherwise 'sorting' their tubiculous
habitations.
'The tubes of the Sabellæ,' says Dr. Williams, 'are soft, flexible,
and muddy. Slimy mucus furnished by the integumentary glands of the
body is the mortar or cement, fine sand molecules are the "stones" or
solid material of the architecture. In the Sabellæ the lime of which
the tubes are built is held in solution in the mucus provided by the
cutaneous glands. It is adjusted in the fluid form, and moulded by
appropriate tools into the required shape. It then _solidifies, too,
under water_, like the "Aberthaw lime." The tube of the Sabellæ fits
closely round the body of the worm; it is slightly elastic, and the
interior is smooth.'
CHAPTER XXIII.
The Solen, or Razor-Fish
'His mansion he extends,
So well concealed beneath the crumbling sands.'
XXIII.
Few people who are in the habit of visiting the sea-shore but must have
noticed the empty shells of the animal about to be described. I allude
to the Solen, or Razor-Shell, commonly so called from its resemblance
to the handle attached to a barber's scythe.
This bivalve, improbable as the statement will appear to the
uninitiated, is one of the most efficient burrowers to be met with on
our shores.
By means of its fleshy foot it digs a hole in the mud or sand.
Sometimes it retreats from the surface to a distance of several feet,
but generally remains sufficiently near to allow its short, fringed
siphons to project above the sand.
In walking along the beach, left bare by the receding tide, the
pedestrian may often perceive little jets of water thrown up at his
approach. These jets proceed from the Razor-Fish in question. Although
we may be several yards from his burrow, his sense of feeling is so
acute, that the faintest vibration of the earth around causes the
creature to retire alarmed within his dwelling.
In many places the Solen is much sought after by the poor, who esteem
it a great luxury. In foreign countries--Japan, for example--it is so
highly prized that we are told, 'by express order of the prince of that
country, it is forbid to fish them until a sufficient quantity hath
been provided for the emperor's table.'
The Irish people, when they go out to catch the Solen siliqua, have
an appropriate song and chorus which they sing, but whether to amuse
themselves or charm the fish 'this deponent sayeth not,' for very
obvious reasons. In general, I should think the less noise the more
likelihood of success to those endeavouring to capture this animal.
'Who has not seen the picture of the stupid-looking boy going warily
out with a box of salt, having been gravely informed by some village
wag that if he would only just drop a pinch of salt on the birds' tails
he would be sure to catch them. We are all familiar enough with this
venerable joke, but not so with its successful application in another
case. This time it is the fisherman, instead of the village boy, who
carries the box. He cautiously slips a little salt into the hole,
which irritates the ends of the siphons, and makes the _Solen_ come
quickly out to see what is the matter, and clear itself of this painful
intrusion. The fisher, on the alert, must quickly seize his prey, or
else it will dart back again into its retreat, whence no amount of
salting or coaxing will bring it out again.'
If after reading the above quotation any person should fancy that in
his mind's eye he perceives at many sea-side places, scores of hardy,
weather-beaten fishermen walking about, each armed with nothing but a
box filled with salt, wherewith to bamboozle the Spout-Fish, he will be
most lamentably deceived. True it is, this plan is sometimes adopted by
children and amateur naturalists, but by fishermen--never. Instead of a
salt-box, these, when in search of their favourite bait, always carry
a kind of harpoon, formed of a piece of iron rod, the end of which is
sharpened to a point.
Having witnessed the Solen throw up his jet of water, and retire
beneath the soil, the fisherman suddenly plunges his instrument into
the orifice. Should the action have been skilfully performed, the
rod will have pierced the animal between its valves, which instantly
retract upon the intruding object. To draw the fish to the surface is
then a comparatively easy task. If the first plunge of the rod be not
successful, the fisher knows full well it would be futile for him to
repeat the attempt, as the object of his attack would quickly burrow
itself down to such a depth as to render pursuit hopeless. Juveniles
at the sea-side, imitating the plan above described, become by practice
very expert in procuring specimens of the Razor-Fish by means of a
piece of wire sharpened at one end.
CHAPTER XXIV.
A Gossip on Fishes &c.,
INCLUDING THE ROCKLING, SMOOTH BLENNY, GUNNEL-FISH, GOBY, ETC.
[Illustration:
1 SMOOTH BLENNY
2 VIVIPAROUS BLINNY
3 SPOTTED BLENNY or Gunnel-Fish
4, 5, 6 THE MONTAGU SUCKER-FISH
(Three illustrations.)
7 SUCKER of THE MONTAGU SUCKER-FISH]
XXIV.
One of the best _bons mots_ that I ever remember to have read was
entitled, 'Punch's Address to the Ocean'--
'With all thy faults I love thee _still_.'
Any landsman who finds himself occupying a seat in a fishing-smack or
oyster-boat while a stiffish breeze is blowing will, I am sure, with
great mental fervour echo the above sentiment.
For myself, I can never take even a short trip on the water without
experiencing some unpleasantness--proving to me that the sea is not 'my
element.' Still, I am one of those to whom the 'salt ocean' is endeared
by early recollections, having been, when a child, frequently among the
aged and mutilated veterans of our country who vegetate on the banks of
the 'silver Thames.'
From the tobacco-stained mouths of some of these old blue-jackets (all
of whom, I may mention, according to their own account, had fought
'alongside of the _galyant_ Nelson'), many strange stories have been
poured into my eager and willing ears, and even now a thrill of delight
is evoked when any of these 'yarns' rise to remembrance. Still, the
truth must be told: ever since I narrowly escaped drowning by plumping
into the water backwards, from leaning against the _unsnibbed_-door of
a bathing-machine, and at another time from being in a boat that, to
my intense horror and dismay, had sprung a leak--I have enjoyed the
sea best when my feet are on dry land; in other words, I like to view
the 'world of fluid matter,' in its various phases, from a distant and
perfectly safe point of view. Nay more, I can always better appreciate
certain of its beauties (at all events during winter time) when seated
by a warm fireside.
When lately in such a cosy position, my thoughts reverted to the
marvellous operations ever going on within the liquid walls of the
great deep. There artifices and stratagems, robbery and murder, and
cannibalism in its worst forms continually occur. On the other hand,
there may be scenes of courtship, touching instances of maternal
affection, such as, were they chronicled, would make our hearts bleed
with truest sympathy. Still, the Rob Roy maxim of
'They should take who have the power,
And they should keep who can,'
seems therein to be carried out with a rigour that would do honour to
the 'bold outlaw Macgregor.' Might there is generally predominant over
right. Fishes eternally prey upon each other; and for such reason, were
it not for the wonderful fecundity of these creatures (one cod-fish,
for instance, producing several millions of ova in a single season), we
should soon have the waters depopulated of all but the monsters of the
deep.
Now, knowing that such a state of things exists--that cannibalism is
of such frequent occurrence, and the dogs of war are there ever let
loose--the inquiry naturally presented itself: Are the inhabitants of
the ocean a happy race or not? According to many writers, the answer
must be given in the affirmative; nay, more, some authors state, and
with good show of authority, too, be it observed, that _fishes are
in reality the happiest of created things_, by reason that they have
no fear or apprehension of death, nor are they subject to pain or
disease, nor, in fact, to any of those ills that _flesh_ is heir to.
These creatures cannot, of course, live for ever; but by a merciful
dispensation of Providence, their final pang endures but for an instant.
The celebrated St. Anthony is among the believers in the consummate
happiness of the finny tribe. There is on record a discourse said to
have been preached by him to an assembly of fish, in which they are
flattered to an amazing extent. It almost rouses one's jealous ire to
find such fulsome adulation bestowed upon the lower animals, at the
expense of all other objects in nature, not excepting _man_ himself.
There is, however, such a singular force and truthfulness in some of
the expressions and sentiments which occur in the Jesuitical discourse
alluded to (given by Addison in his 'Remarks on Italy'), that I cannot
resist the temptation of quoting a few of its most prominent passages.
We are told that St. Anthony, feeling annoyed at certain heretics not
listening devoutly to his preaching, he determined to teach them a
lesson; and for this purpose went down to the sea-shore, and called
the fishes together in the name of God, that they might hear his holy
word. The fish soon swam towards the speaker in vast shoals, and,
having ranged themselves, according to their several species, into a
very beautiful congregation, were addressed just as if they had been
rational creatures.
The sermon commences in the following words:--
'My dearly-beloved Fish,--Although the infinite power and goodness
of God discovers itself in all the works of his creation, as in the
heavens, in the sun, in the moon, and in the stars--in the lower world,
in man, and in other perfect creatures,--nevertheless, the goodness of
the divine Majesty shines out in you more eminently, and appears after
a more particular manner, than in any other created beings.
'It is from God, my beloved fish, that you have received being, life,
motion, and sense. It is he that has given you, in compliance with your
natural inclinations, the whole world of waters for your habitation.
It is he that has furnished it with lodgings, chambers, caverns,
grottoes, _and such magnificent retirements as are not to be met with
in the seats of kings or in the palaces of princes_!
'You have the water for your dwelling--a clear, transparent element,
brighter than crystal; you can see from its deepest bottom everything
that passes on its surface. You have the eyes of a lynx or of an Argus;
you are guided by a secret and unerring principle, delighting in
everything that may be beneficial to you, and avoiding everything that
may be hurtful; you are carried on by a hidden instinct to preserve
yourselves, and to propagate your species; you obey, in all your
actions, works, and motions, the dictates and suggestions of nature,
without the least repugnance or contradiction.
'The cold of winter and the heat of summer are alike incapable of
molesting you. A serene or a clouded sky are indifferent to you. Let
the earth abound in fruits or be cursed with scarcity, it has no
influence on your welfare. You live secure in rains and thunders,
lightnings and earthquakes; you have no concern in the blossoms of
spring or in the glowings of summer, in the fruits of autumn or in the
frosts of winter. You are not solicitous about hours or days, months or
years, the variableness of the weather or the change of seasons.'
The saint still further 'butters his fish' by reminding them, among
other things, that they were specially favoured by God at the time of
the universal deluge, they being the only species of creatures that
were insensible of the mischief that had laid waste the whole world! He
then begs of them, as they are not provided with words, to make some
sign of reverence; give some show of gratitude, according to the best
of their capacities; express their thanks in the most becoming manner
that they are able, and be not unmindful of all the benefits which the
divine Majesty has bestowed upon them.
He had no sooner done speaking, but behold a miracle! The fish, as
though they had been endued with reason, bowed down their heads with
all the marks of a profound devotion, and then went joyously bobbing
around with a kind of fondness, as in approval of what had been spoken
by the blessed father, St. Anthony.
Many of the heretics, as a matter of course, were converted at
beholding the miracle; and the polite and pious little fishes, having
received his benediction, were dismissed by the saint.
Shakspeare authoritatively asserts that--
'Travellers ne'er do lie,
Though fools at home condemn them.'
Here I beg to differ with the sweet Bard of Avon, who, I am sure, would
have retracted his statement had he read the above fishy discourse,
and also the following among many other strange anecdotes which are
published regarding the 'denizens of the deep.'
An Eastern traveller tells us that, 'in a certain river whose waters
flow from Mount Caucasus into the Euxine, there arrives every year a
great quantity of fish.' This information not being particularly novel
in regard to most rivers, will fail to excite surprise in the mind of
the reader. A different result, however, will follow when he hears
that, according to Abon-el-Cassim, 'The people cut off all the flesh on
one side of those inhabitants of the deep, and let them go. Well, the
year following,' as this veracious writer avers, 'the same creatures
return and offer the other side, which they had preserved untouched; it
is then discovered that new flesh has replaced the old!'
This account reminds us of the tale of the traveller who reported that
he had seen a cabbage, under whose leaves a whole regiment of soldiers
were sheltered from a shower of rain. Another, who was no traveller
(but the wiser man), said he had passed by a place where there were
four hundred braziers making a cauldron--two hundred within, and two
hundred without beating the nails in. The traveller, asking for what
use that huge cauldron was, he told him, 'Sir, it was to boil your
cabbage!' A wittily severe, but deserved rebuke.
There are many other statements regarding fishes which, although
curious, are, nevertheless, to a certain extent true.
The Chinese, for instance, who breed large quantities of the well-known
gold-fish, call them, it is said, with a whistle to receive their food.
Sir Joseph Banks used to collect his fish by sounding a small gong; and
Carew, the historian of Cornwall, brought his grey Mullet together to
be fed by making a noise with two sticks.
In spite of these accounts, there are many writers who affirm that
_fishes do not possess the sense of hearing at all_; and certainly
a belief that these creatures are gifted with such a faculty is not
necessary, in my opinion, in order to explain the above-mentioned
phenomenon.
At the fountains, in the gardens of Versailles, the writer has seen
numbers of fishes flocking together and anxiously waiting for the
subscriptions of the visitors. Now, had a bell been rung, these
animals, doubtless, would have appeared at the edge of the fountain as
usual; but had the bell _not_ been sounded, and any human figure been
visible, they would have taken up the self-same position.
I have, at various times, kept packs of fishes (Blennies, &c.), and
tamed them, so that each member would feed out of my hand. For some
time I used to attract them to the side of the vessel in which, they
resided by striking a wine glass with a small stick; but I also noted
that if I made myself visible, and remained silent, while handing down
a few fish mouthfuls, that the whole pack followed as readily as if I
had sounded the mimic gong. Nay, whether I offered any bribe or not,
and silently approached their crystal abode, the whole family would
immediately flock in great haste towards me.
The tameness of these little creatures was somewhat remarkable. On
numberless occasions I have taken them up in the palm of my hand,
without the slightest opposition on their part, and then stroked and
smoothed them on the back, as I would do a bird. At such times they
made a kind of musical chirp, expressive of pleasurable emotion, and
seemed in no hurry to escape into their native element even when I laid
my hand in the water.
Such delightful confidence was always rewarded with some dainty.
Dr. Warwick relates an instance of instinct and intelligence in the
Pike, which is so remarkable that I am sure my readers will be pleased
to be made acquainted with it. I am the more induced to transfer it
to these pages, from the remarks with which the doctor closes his
narrative. From reasons stated above, the reader will be prepared to
learn that I do not consider the statements therein advanced--that
fishes are really sensible to sound--by any means conclusive.
When residing at Dunham, the seat of the Earl of Stamford and
Warrington, he (Dr. Warwick), was walking one evening in the park,
and came to a pond where fish intended for the table were temporarily
kept. He took particular notice of a fine pike of about six pounds
weight, which, when it observed him, darted hastily away. In so doing
it struck its head against a tenterhook in a post (of which there were
several in the pond, placed to prevent poaching), and, as it afterwards
appeared, fractured its skull, and turned the optic nerve on one side.
The agony evinced by the animal appeared most horrible. It rushed to
the bottom, and boring its head into the mud, whirled itself round with
such velocity that it was almost lost to sight for a short interval.
It then plunged about the pond, and at length threw itself completely
out of the water on to the bank. He (the doctor) went and examined it,
and found that a very small portion of the brain was protruding from
the fracture in the skull. He then carefully replaced this, and with a
small silver toothpick raised the indented portion of the skull. The
fish remained still for a short time, and he then put it again in the
pond. It appeared at first a good deal relieved, but in a few minutes
it again darted and plunged about until it threw itself out of the
water a second time. A second time Dr. Warwick did what he could to
relieve it, and again put it in the water. It continued for several
times to throw itself out of the pond, and with the assistance of the
keeper, the doctor at length made a kind of pillow for the fish, which
was then left in the pond to its fate. Upon making his appearance at
the pond on the following morning, the pike came towards him to the
edge of the water, and actually laid its head upon his foot. The doctor
thought this most extraordinary, but he examined the fish's skull and
found it going on all right. He then walked backwards and forwards,
along the edge of the pond for some time, and the fish continued to
swim up and down, turning whenever he turned; but being blind on the
wounded side of its skull, it always appeared agitated when it had that
side toward the bank, as it could not then see its benefactor. On the
next day he took some young friends down to see the fish, which came
to him as usual, and at length he actually taught the pike to come
to him at his whistle, and feed out of his hands. With other persons
it continued as shy as fish usually are. He (Dr. Warwick) thought
this a most remarkable instance of gratitude in a fish for a benefit
received, and as it always came at his whistle, _it proved also what he
had previously, with other naturalists, disbelieved, that fishes are
sensible to sound_. (?)
On hunting among the rock-pools by the sea-shore, several peculiar
little fishes are frequently to be found, and although some of them
cannot be considered suitable for the aquarium, still, for the reader's
information, it may be as well that I devote a brief space to a
description of the peculiarities of each.
By far the most interesting of all the finny occupants of the
rock-pool, is, to my taste, the Smooth Blenny, or, as it is variously
termed, Shanny, or Tansy. It is also more abundant than many other
species, and may therefore be readily captured during summer. The
Blenny varies from two to five inches in length. The back is ornamented
with exquisite markings, but the most characteristic features are the
peculiar bluntness of the head, and the brilliant crimson dot both on
and immediately beneath the eyes.
Although easily tamed, the Blenny, in his native haunts, appears to
be the most timid of animals, darting with the rapidity of lightning
to the shelter of some stone or overhanging weeds at the remotest
indication of approaching footsteps, or the faintest shadow of a human
form being cast on the water.
When desirous to procure a specimen, it is best to choose as small a
pool as you can for your hunt. Drop in your net at one end, and as the
Shanny precipitately retreats to the other, give him chase. Having
arrived at the extremity of his domain, he will endeavour to hide among
the weeds, but if you hold your net across the pool with one hand, and
with the other lift up a stone or beat the bushes, the little fellow
will become greatly excited, and darting out, of course, unwillingly,
falls into the snare prepared for him.
Having gained your prize, do not handle it, but placing your finger
under the net, tilt it over the mouth of the bottle, and allow the
Blenny to fall as gently as possible into the water. You need be under
no uneasiness after introducing him to the aquarium about the nature of
his diet. He is far from being epicurean in his tastes. I supply mine
according to my whim at the moment, with whatever is at hand, a bit of
fowl, roast beef, or the like.
The only caution I adopt when giving animal food to the Blenny is to
remove all traces of fat. I mince their food into minute particles, and
having sufficiently moistened it, I place a morsel upon a hair pencil.
This attention to their comforts the Blennies soon learn to appreciate,
and will, after a while, display at meal times the sagacity of larger
animals.
Perhaps the simplest plan to adopt is to cut open a mussel and throw
it into the tank. A considerable deal of amusement, moreover, is often
to be obtained by watching the fishes engaged at such a meal. How
they toss the valves of the Mytilus about, and snap at each other's
tails! How vexed they become if by accident the shelly dish is turned
topsy-turvy, and resists all their manœuvres to reverse it so as
to get at the meat! The valves of a large mussel will sometimes be
literally cleaned out by some half dozen Blennies in the course of an
hour.
I have noticed a singular fact in connection with the Blenny--namely,
_that they do not all increase in size as they grow older_. Out of five
that I kept domesticated for more than two years, one specimen remained
at the end of that period of the same size as when I first made its
acquaintance in a rock-pool by the sea-shore, while its companions had
greatly increased their proportions. But let me in justice add, that
if my little finny pet failed to increase in corpulency, it gained
largely in intelligence. Who is there that has not seen children, short
in stature, and comparatively old in years, who deserve the epithet
applied to them by the vulgar, of 'little--but _knowing_.' This remark
would apply with great truth to my 'little Dombey' fish.
Before becoming expert in carrying out the plan (which will be fully
detailed hereafter) for clarifying the water of an aquarium which has
become opaque from superabundant vegetative growth, I had to submit to
many annoying failures. Thus it was in a certain instance.
I had cleaned out my tank, refilled it with partially purified water,
and again inserted the various animals constituting my 'stock.'
Emboldened by the success which had attended my operations, I thought a
still further dose of diluted acid might be added, in order thoroughly
to remove the greenish hue of the water. A few minutes showed me
the folly of not letting well alone, for soon flakes of discharged
vegetation were precipitated to the base of the vessel, covering it
with a coating of fur.
The poor Blennies speedily showed signs of distress, and changed
colour, as they generally do, upon the most trifling cause. Instead of
dark brown or black, their bodies appeared of a yellowish tint, spotted
with white. Such a change was lovely to the eye, but, alas! it was--
'The loveliness in death,
Which parts not quite with parting breath.'
The little creatures jumped and dived about in all directions, all
their motions being extremely violent. I quickly perceived the error
which had been committed, and, moreover, discovered to my chagrin that
such error could not possibly be rectified for some time, on account of
my not having by me any reserve of pure salt water. Taking several of
the fishes in my hand, I stroked their backs with a camel-hair pencil,
and was pleased to find that as their alarm subsided their natural
hue returned. My being obliged to place my pets in their unhappy and
pestilential home again was, as the reader may suppose, a source of
regret to me; but I had some hopes that they might by chance survive,
and become used to the 'vapour of their dungeon,' at all events until
such time as I could hasten to the sea-side and procure a new supply
of water. My expectations of such a result were built upon the fact,
that although four of the fishes had changed colour, the small Blenny
still retained its natural hue. How did this happen? it will be asked.
I answer, by little Dombey (doing as his brethren had always hitherto
done in similar circumstances) leaping on to a ledge of rock that
projected out of the water, and there breathing the fresh air in safety.
On the following morning I peeped into the vessel, and saw by their
upturned gills that all my finny proteges were dead!
'All my pretty ones?
Did I say all?'
All except the smallest of the pack, he was still dressed in his sombre
coat, and gracefully reclining upon the rocky couch above mentioned.
How thankfully he received the breakfast that I temptingly offered upon
the tips of my feeding brush, and how grateful he seemed to be, when,
after the lapse of a few hours, I was enabled to let him float again in
his pure native element, a fresh supply of which had been procured with
as little delay as possible!
The Viviparous Blenny differs from the other British Blennies 'in the
circumstance to which its name refers--that of bringing forth its young
alive, which seem perfectly able to provide for themselves from the
moment they are excluded.'
It is a most gentle, graceful-looking fish, but as far as my experience
goes, one that is impossible to tame, or rather, I should say,
embolden. All my efforts to domesticate various specimens have proved
unavailing; and in spite of the most earnest and kindly attention,
they have generally pined away and died within a week after their
introduction to the aquarium.
From the illustration on Plate 12 the reader will have no difficulty
in recognising the original, should he by chance meet with it hiding
among the tangle, or beneath the stones by the sea-shore.
The spotted Blenny, Butter-Fish, or Gunnel-Fish, as it is variously
termed, is found lurking under stones in the same places as the
preceding. In the north of Scotland it is called 'cloachs,' and is used
extensively as a bait for larger fish. When disturbed, it wriggles its
body about in the muddy bottom of the rock-pool like an eel, for which,
indeed, it is occasionally mistaken.
Its length varies from three to nine inches; the depth only half an
inch; the sides very much compressed and extremely thin.
The dorsal fin consists of seventy-eight short spiny rays, and runs the
length of the back almost to the tail. The most conspicuous feature in
the Gunnel-Fish are the eleven round spots which occur at the top of
the back, and reach the lower half of the dorsal fin; they are black,
half encircled by white.
The tail is rounded, and of a yellow colour. The back and sides are of
a deep olive; the belly whitish.
In its young state I have had this fish live in my aquarium for several
months, but it never seemed to be happy or contented.
The Five Bearded Rockling is almost as great a favourite with the
writer as the Smooth Blenny. It is a very pretty fish, and may be
easily tamed. In the course of a week I trained one to feed out of my
hand, and when I put my finger in the water the fish would rub against
it with its head, just as a favourite cat frequently does against the
leg of a person with whom it is very familiar; moreover, if I moved the
intruding digit with a circular motion through the water, the Rockling
would waltz round the tip with evident signs of pleasure.
This fish is often found in tide-pools, and may readily be identified
by the prominent appendages attached to its head, to the presence of
which, the Rockling owes its familiar appellation.
The Goby (_Gobius unipunctatus_), or, as it is more popularly termed,
One-Spotted Goby, is frequently found inhabiting the same pool as the
Blenny or the Rockling. The distinguishing character of this pretty
creature is the black spot which is situated between the fifth and
sixth ray of the first dorsal fin. Its length is usually about one, or
one and a half inches; specimens have, however, sometimes been found on
the shores of the Frith of Forth, that measured nearly three inches.
The colour of the Goby is very changeable. If the animal is labouring
under excitement, its body assumes a deep brownish tint, approaching
in some instances to black; this gives place to brown, drab, and even
amber, or yellowish white.
The Goby possesses the power of attaching its body to any object by
means of its ventral fins, which become united together in the form of
a funnel.
Another species (_Gobius bipunctatus_), or Two-Spotted Goby, is
generally found among the _Fuci_, in rocky situations. Its name is
derived from a dark spot which is distinctly apparent on each side,
near to the origin of the pectoral fin.
The head and upper part of the body is dark brown,--the under part of
the head and belly white or pale drab.
Allusion has already been made to the peculiarity of the Gobies
affixing their bodies to rocks or other substances, by means of a
sucker formed by the junction of the ventral fins. The adhesive power
in question, which this class of creatures possess, is very limited
as compared with that which is exercised by the true sucker fishes,
and especially by the members of a certain species, whose bodies are
furnished with two distinct organs of adhesion.
The extraordinary adhesive powers of the Lump-Sucker, for instance,
have been tested by several writers. One observer states, that a fish
of moderate size has been known to suspend a weight of above 20 lbs.,
upon which it had accidentally fastened itself. Mr. Pennant says still
more, for he has known that, in flinging a fish of this kind just
caught into a pail of water, it fixed itself so firmly to the bottom,
that, on taking it by the tail, the pail was lifted up, though it
contained several gallons of water.
To descend from the largest to the smallest species, we arrive at the
Montague Sucker-Fish, or, as it is sometimes called, the Diminutive
Sucker, one of the most interesting little creatures to be met with
at the sea-shore. At the coast near Edinburgh I have met with many
specimens, equally well in the spring or winter season, as during
the summer months. At such locality this species may therefore be
pronounced common; yet it is comparatively unknown to most 'collectors'
in the neighbourhood. Many, indeed, contend that my designation is
erroneous. But having taken considerable pains to satisfy my mind upon
the subject, I have no hesitation whatever in stating that the little
fish in question is identical with that of the Montague Sucker.
Donovan, in his 'Natural History of British Fishes,'[19] was the first
to illustrate and publish an account of this _petite_ gem of ocean.
His figures are copied from drawings made by Colonel Montague, who
also furnished the description of the specimen delineated. With the
important exception of the sucker--an organ of adhesion which is very
nearly correct--the general appearance of the Diminutive Sucker-Fish
as figured, is not at all satisfactory. Perhaps this is not to be
wondered at, when we remember that the specimen from which the sketches
were taken was very small indeed. Moreover, it was diaphanous, and is
depicted as being principally transparent, spotted, and tinged with
pink.
[19] This splendid work, which was published in five volumes, between
the years 1802-8, contains 120 exquisite illustrations, all, _with
the solitary exception, unfortunately, of the Montague Sucker-Fish_,
accurately drawn and coloured from living specimens, procured at vast
trouble by the author.
The Diminutive Sucker, in its adult state, is said to be from two to
three inches in length; consequently Colonel Montague's first specimen
must have been an extremely young one.
The usual colour is deep orange, varied with minute dark spots. The
under parts of the body and throat are of flesh colour; the centre of
the sucker being faintly tinged with crimson.
I have seldom met with specimens measuring more than one, or one and a
quarter inches. It is a marked peculiarity in this Sucker-Fish, that
when adhering to any substance it has a constant habit of curving the
tail towards the head. In such position it will remain motionless for
several hours.
There is little difficulty in capturing the Montague Sucker in its
native haunts. It does not possess the power of darting to and fro with
the speed of the Blenny, or most other fishes, but progresses through
the liquid element with a peculiar quivering motion.
It is not a fish that can be recommended for the aquarium. A fortnight
to three weeks is the longest time that I have been able to keep a
specimen alive; indeed, until I adopted the plan of allowing each
little captive to remain quiet and undisturbed in a dark and shady
place, death ensued in the course of one or two days.
My illustrations (Plate 12) having been carefully drawn and coloured
from a living specimen, the student will, I trust, find no difficulty
in recognising the Diminutive Sucker, should he be so fortunate as to
meet with it in a rocky pool.
'There is also a fish called the Sticklebag, a fish without scales, but
hath his body fenced with several prickles. I know not where he dwells
in winter, nor what he is good for in summer, but only to make sport
for boys and _women anglers_.' Thus contemptuously does dear old Izaak
speak of the Sticklebag, or Stickleback, as it is now termed, one of
the most amusing and interesting members of the finny tribe. I have
frequently transferred specimens of the Stickleback from fresh water to
salt water, and found them live quite as well in the latter as in the
former.
The contrast, however, between the appearance of the three spined
Stickleback, when first taken from the sea, and one captured in the
fresh water pond is very remarkable. The first is dressed in a gorgeous
coat of varied colours. Around the mouth and belly it is bright
crimson, on the upper part of its body various tints of green prevail;
while in the pond specimen no red colour is visible at all, but only
white blended with green.
In addition to _Gasterosteus aculeatus_, whom we have above alluded
to, there is another species, _G. spinachia_, or Fifteen-Spined
Stickleback, which is also an inhabitant of rock-pools by the
sea-shore, but unlike the first-mentioned, is never found in fresh
water. Both species possess one peculiarity in common, a description of
which will form an appropriate conclusion to this chapter. I allude to
their nest-building habits, which has only of late years been proved to
exist, although Aristotle has recorded the same fact regarding a fish
(_Phycis_) in the Mediterranean Sea, which was known to make a nest and
deposit its spawn therein.
The duties of mason and architect are invariably undertaken by the
male Stickleback. His materials are of course very limited, still his
labours are skilfully and even artistically performed. Having chosen a
suitable spot as a foundation for his house, he collects some delicate
sea-weeds, gravel and sand, and with these materials, aided by a
glutinous fluid which is given off from his body, the house is built.
When completed, and not before, he seeks out his mate, and invites
her to take possession of her newly formed home. If she shows any
affectation or coquetishness, he does not hesitate to nip hold of her
tail, and urge her forward by equally expressive signs. Soon, like a
dutiful little pet, she enters, and having deposited spawn, retires
again, leaving her lord and master to guard the casket and its living
treasure. This task, though extremely arduous, he adopts with pride and
gratification.
How so small a creature can bear up so long under such a state
of apparent excitement appears marvellous. His assiduity is most
extraordinary. By night he rests beside the nest, and by day, if he can
possibly hinder it, he allows nothing to approach. When there are other
members of the Stickleback family in the aquarium, numerous combats
are sure to ensue, for as the young and transparent offspring of one
fish are deemed a great dainty by the non-parental body, the latter
invariably endeavour to satisfy their cannibal propensities at the
harrowing expense of their neighbours.
When the spawn are hatched, fresh care devolves upon the parent, in
order to keep them within the nursery, and protect them from the greedy
mouths of the larger fish, always on the look-out for tit-bits. Should
one of the little fishlings stray beyond the prescribed bounds, the
watchful parent darts after it, and in an instant his jaws close over
the wanderer apparently for ever, but in fact only for a time, for
swimming quickly back the old fish puffs out the straggler into its
nest lively and uninjured.
CHAPTER XXV.
On the Formation of an Aquarium, &c.
'And so I end this little book, hoping, even praying that it may
encourage a few more labourers to go forth into a vineyard which those
who have toiled in it know to be full of ever fresh health, and wonder,
and simple joy, and the presence and the glory of Him whose name is
Love.'--C. KINGSLEY.
[Illustration: A SKETCH FROM NATURE
1 Mussels attached by their byssus threads to the glass
2 Fronds of _Chondrus chrispus_
3 Fronds of _Delesseria Sanguinea_
4 Fronds of _Ulva latissima_]
XXV.
No ornament for the drawing-room or parlour can possibly be more
beautiful than a well-stocked and tastefully-arranged aquarium; nor is
there one likely to be productive of a greater amount of pleasure and
amusement. And it is instructive as well as amusing, for by means of
it the statements of writers relative to the habits of certain marine
animals may be verified by personal observation, and even difficult
problems in natural history satisfactorily solved. Aided by one of
these 'mimic oceans,' let the reader commence the practical study of
marine zoology, and I have little fear of his ever becoming tired of it.
'Age cannot wither it, nor custom stale
Its infinite variety.'
When pursued even in the most humble way, this recreation yields a
degree of interest greater than any other 'hobby' can produce, at least
in an equal space of time. If engaged in business during the day, the
student can always devote an hour morning or evening to the aquarium,
and when least expected, some circumstance will take place to excite
his wonder, and fill his mind with deep and devout reflection.
Moreover, the young naturalist will undoubtedly derive pleasure from
his endeavours to establish published facts relative to many of his
little prisoners; pleasure in noting down any interesting anecdote that
may occur; pleasure in knowing that his time is being profitably spent;
and above all, that he is making himself acquainted with objects framed
with marvellous skill and care by the hand of the Almighty:--
'Wonderful indeed are all His works,
Pleasant to know, and worthiest to be all
Had in remembrance, always with delight.'
Without further preface, I shall now proceed to offer some practical
hints relative to the establishment of a marine aquarium. And, as some
of my readers may be perfectly unacquainted with the subject, I shall
treat it in as simple a style as possible. If, however, the experienced
zoologist will kindly follow me to the end of the chapter, it may be
that he will find some hints sufficiently new and useful to repay him
for his trouble.
First, then, in regard to the tank. This indispensable requisite may be
procured at certain shops in almost every town in the United Kingdom.
Its price varies from two or three shillings to £20. The expensive
kinds are generally oblong in form, but their construction being
somewhat intricate, they are apt to get out of order, unless made by
skilful and thoroughly competent artistes. Under certain circumstances,
there is no doubt that an oblong tank of moderate dimensions is a great
desideratum; but what I wish particularly to impress upon the mind of
the reader is, that a large tank is not at all necessary in order to
study the habits of marine animals; indeed, the more capacious the
vessel, the more difficult becomes the task of watching the secret
movements of any of its occupants. On this account it not unfrequently
happens that a common glass tumbler becomes of much greater service to
the student than the most elaborate aquarium.
The tanks which I use are circular in form, the largest being not more
than sixteen inches in diameter, by seven inches in depth. Its cost
was four shillings. Each one rests on a base of mahogany, elevated on
turned legs to a height of nine inches.
Some persons object to the circular tank, on the ground that its
occupants when seen from the sides appear magnified. This fact, as
I have elsewhere remarked, is rather a recommendation with me, as
it presents more distinct views of each movement in the vessel, and
whenever I wish to see the objects of their natural size, I can do so
by looking in from the top.
On the edge of the tank are placed three chips of gutta percha in which
are inserted three steel pins with brass heads; on these there is
laid a circular piece of common glass, cut two inches larger than the
diameter of the tank. As the 'pins' are about three-quarters of an inch
above the tank, they allow a current of air to pass over the water,
and also prevent, to a certain extent, particles of dust from falling
in. On the edge of the movable lid I _paste_ some crimson lace, which
serves for ornament, and also prevents the glass from cutting the hand
of any person moving it about. Sometimes I have a circular piece, about
four inches in diameter, cut out of the centre of the glass lid, which
allows the latter to be lifted off easily.
A glass syringe to aerate the water occasionally, a camel-hair pencil,
an ivory crotchet pin, and a pair of gutta percha forceps, complete the
whole machinery of the aquarium, the cost of which is so trifling that
the poorest person might manage to procure them.
One great point in favour of an aquarium, and one by no means generally
understood is, that having once filled the tank with salt water, it
will last for months, and even years, if proper care be taken, without
requiring one particle of sea-water to be again added; for as the water
evaporates, the salt falls to the bottom, and the deficiency may be
supplied with _fresh_ water from the cistern or filter. In order to
ascertain when the sea-water is of the proper density, you require
to have a 'gravity bubble,' which can be had for sixpence. This may
always be kept in the tank. When 'all's well' it sinks to the bottom,
and when anything comes amiss it rises to the surface, but falls again
quickly upon the introduction of the fresh water.[20]
[20] _Vide_ author's "Sea-side and Aquarium."
A more simple plan is, to mark on the glass the height of the fluid
when the tank is first filled, then as the water sinks, raise it again
to its original level by means of fresh water.
Many persons decline starting an aquarium on account of the great
difficulty of procuring a proper supply of sea-water. This objection,
of course, can be offered only by those who happen to reside inland;
but even these need not now be discouraged, for an ingenious plan has
lately been devised for sending the commodity in question through the
post!
Mr. Bolton, chemist, Holborn Bars, London, supplies, not sea-water, but
'marine salts for the instantaneous production of sea-water,' About six
ounces is sufficient to make a gallon, by the application of _fresh_
water. The saline material here alluded to, is not an artificial
chemical compound, but is produced by the simple process of evaporating
sea-water itself. Those individuals so fortunate as to possess a marine
villa, or any other more humble residence at or near the sea-coast,
have no occasion to resort to the scheme above-mentioned for filling
their tanks, a pure supply of sea-water being attainable with scarcely
any trouble whatever. A stone jar should be kept for this purpose only,
and care taken that the vessel is perfectly free from any smell, as
that of spirits, dirty corks, or the like, as any such impurity would
quickly spoil the water.
It may not be uninteresting to some of my readers to know, that in
France an aquarium cannot be established with the same ease as in
England. In the former country 'the whole contents of the sea itself
is a contraband article,--that is, the contents of the salt sea of
the English Channel or the Atlantic Ocean.' One writer tells us, that
staying on the French coast, he kept sea-anemones alive in glasses,
but was frequently warned by his friends to be careful how he fetched
water from the sea, lest the custom-officers should interrupt him. 'My
bottle,' to use the writer's own words, 'being very small, they let
it pass, on the principle that the law does not care about extremest
trifles; had it been a pailful, the case would have been different. A
lady keeping a marine aquarium, explained her wants to the local head
of the customs. He came and saw it--found it beautiful, and being a
gentlemanly man, with some love for natural history, he gave a written
order for the procuring of any reasonable quantity of water from the
sea. Every time the needful element was brought from the shore, it was
accompanied by its passport, as formally as if it had been a cask of
wine, or a suspicious stranger. French salt sellers thus enjoy the
height of protection; they are protected even from their colossal
competitor, the sea!'
I do not know a prettier sight than that exhibited by a healthy
aquarium on a fine summer's day; the effect of the sunshine upon it
being to cause innumerable bubbles of oxygen--that look like balls of
quicksilver--to form on every weed, shell, and smallest pebble. On
looking through the transparent sides of the vessel, small particles
hitherto resting on its base, may be seen slowly arising to the
surface of the water, each buoyed up by a miniature gas balloon. The
broad, ribbon like fronds of the ulva, from the self-same cause, float
upwards, and reflect a beauteous emerald hue upon all objects that lie
beneath; while the glass bulb, placed in the tank as before stated, to
denote the density of the water, at such a time belies its mission,
and covered with numerous argent globules, mounts gracefully in
companionship with the sea-weed, until shades of evening approach, when
its buoyancy gradually subsides, and once more it falls to its original
resting-place.
Wherever the above phenomenon is apparent, rest assured that the
aquarium is in good condition. It is, in fact, to the oxygen thus given
out by the plants and infant vegetation that the animals owe their
existence. If no algæ were introduced, the water would become impure,
and unless changed often, your little colony would surely die,--at
least those of its members who were unable to rise above the fluid, and
occasionally breathe the fresh air.
The secret herein involved, that animal and vegetable respirations
counterbalance each other, has only of late years been discovered; yet
it is apparent to any observing eye at the sea-shore; there we never
meet with a rock-pool containing living animals, that is not more or
less adorned with sea-weeds.
The green Lettuce Ulva, so abundant in rock-pools, the sea-grass, which
covers almost every fixed object at the sea-shore, or the well-known
dulse or Chondrus Crispus, form the only sea-weeds that it is necessary
to introduce into an aquarium. In fact, one or two fronds of the Ulva
Latissima alone, will answer perfectly well to purify the water of even
a comparatively large tank. I have often been surprised to find how
small a quantity of algæ was required for the purpose mentioned. After
allowing a single frond to float for a few days in a tank, in which
some sea-water was newly deposited, I took it out, and for an entire
twelvemonth the water remained healthy and as clear as crystal.
The arrangement of the 'stock' of an aquarium is quite a matter of
taste; perhaps no two persons adopt precisely the same plan. It may,
therefore, be advisable, as this matter is so arbitrary, for the writer
to state how his own tanks are mapped out, leaving it to his readers
to imitate the arrangements, or adopt a style of their own as they may
think proper.
At one time I used to make a grounding of sand, but this plan is not
to be recommended, even though it be one highly approved of by several
species of crabs, &c. White pebbles do very well, but I now prefer to
cover the base of the tank with crushed shells, washed very clean.
The following is a sketch of one of my tanks as it at present stands:--
In the centre of the vessel is a _semi-circular arch_, formed of pure
white Sicilian marble, which has to my eye a most pleasing appearance.
Around it, and indeed over the entire floor of the tank, are strewn
chippings of the same material as the centre piece itself.[21] From
the arch, at certain intervals, hang various sized specimens of the
_Mytilus edulis_, which have gradually advanced to their more or less
elevated positions entirely by their own unaided exertions. Near hand
a hardy _A. mesembryanthemum_ has taken up his abode, and sits with
ever expanded tentacles, motionless and happy. On either side of
the Anemone is deposited a riband of Doris spawn, that undulates to
and fro whenever by any chance the water is in the slightest degree
disturbed. Several soldier crabs, of course, act as sentinels of the
tank, and appear to be ever 'on duty,' marching about in all parts
of their subaqueous habitation; while beneath the marble fragments
repose, each with his 'weather eye' open, a small _Maia squinado_, two
long-armed crabs, and a small _Carcinus mænas_. On the sides of the
vase rest a Limpet, a Trochus, and two fine Periwinkles, with skin
of glossy blackness. The shells of either 'Buckie' is covered with
myriads of quicksilver globules, that rest on the tips of the young
and rising vegetation like dew upon the bladed grass. As I write,
upon the inner surface of the water, like a fly upon the ceiling of
a room, an Eolis and two pearly white Dorides lie idly floating in
close companionship. Beneath them, upon the verge of the aperture of a
large empty whelk shell, sits a pretty, cream-coloured Plumose Anemone
(_A. dianthus_). On two blocks of stone repose several specimens of
that mysterious animal the Pholas, who, by my unkindness, are thus
made to become members of the marine 'houseless poor.' Several young
specimens of these bivalves are seated, in a piece of rock, and daily
engaged in 'boring.' A stick of wood, formerly the slender twig of
a tree, is thickly clustered with fairy-handed acorn barnacles and
serpulæ, and being placed against the glass, the movements of these
singularly beautiful creatures can be watched with ease. Then there are
two Star-fishes, a pack of three little Blennies, and a Five-bearded
Rockling, whose singular movements I have previously alluded to.
Against the arch some fronds of ulva are anchored, while at chosen
spots specimens of delicate sea-weeds are also fixed--these rising up,
and being magnified through the sides of the vase, have a pleasing
effect, even to the eye of a child.
[21] The arch was cut from one of the waste pieces, of which there are
always a large number, lying in a marble mason's yard, and cost but a
few pence. The 'chippings' may be had in most cases for the trouble of
carrying them away.
It is a pretty sight to watch the fishes glide under and around the
marble arch, or throw themselves upon its highest point, there to enjoy
the fresh air, and have a pleasant 'crack' together. This expression is
literally correct, for the Blennies, when thus situated, usually make a
kind of noise not inaptly expressed by snapping the nail of the thumb
and finger together.
The foregoing animals which constitute the entire stock of one tank,
are, I am proud to state, all in a healthy condition, and if we may
judge by appearances, all contented and happy. It will be from no fault
of mine if they do not long continue thus, and exhibit no signs of
yearning for their native haunts by the sea-shore.
'Those gay watery grots--
Small excavations on a rocky shore,
That seem like fairy baths or mimic wells,
Richly embossed with choicest weed and shells,
As if her trinkets nature chose to hide
Where nought invaded but the flowing tide.'
In another tank I have introduced as a centre object a fine piece of
white coral, the higher branches of which rise above the surface of the
water. The roughness of the coral seems to be much approved of by many
of the animals, who are not slow to avail themselves of the facility
thus afforded them of climbing and otherwise exercising their peculiar
propensities. When purchasing coral, care must be taken to procure a
specimen that has not undergone any cleaning process, for although such
may be more pleasing to the eye, it is not so suitable for a 'centre
piece' as the cream-coloured, and less expensive coral.
A third aquarium which I possess is fitted up in a somewhat novel
style, which offers, for certain purposes, some slight advantages over
others that I have seen employed. It can be adopted in almost any kind
of tank; but the one under consideration is circular in form, and is,
in fact, a bell-shaped inverted fern glass, the knob of which is sunk
into a stand of wood supported on three legs.
The plan alluded to, which was suggested to the writer by an ingenious
friend,[22] consists of the introduction of a floating centre piece
composed of gutta percha, which serves as a resting place for various
small animals, such as Actiniæ, Mussels, Barnacles, Serpulæ, and
even Pholades and Cockles. At the base of the vessel, which is quite
uncovered, rest sundry members of the crustaceous family, whilst
fishes of various kinds swim freely about over the entire vessel free
from all annoyance.
[22] Mr. Walter Hardie of Edinburgh, who has been my companion in many
a delightful excursion among the rock-pools of the shores of the Frith
of Forth, and to whom I feel myself greatly indebted for much valuable
information relative to the subject of marine zoology.
The question will doubtless be asked, 'How can I procure the centre
piece here spoken of?' I answer, Make it yourself; a little skill
combined with patience and gutta percha being all that is required. The
following directions will serve to aid the young reader who may wish to
test his manipulative powers.
Procure a thin piece of gutta percha, and lay it in hot water for a few
minutes until it is thoroughly soft and pliable. Then get a globe--an
orange will do if nothing better offers--and cover it with the above
material. Having done this, throw it into cold water, and when hard,
cut the fruit in two, so as to leave the gutta percha cast to the shape
of each half.
Next make a circular tray about eight or nine inches in diameter, and
turn up its edge about half an inch all round. Then heat the brim of
each cup, and fasten them to the centre of the upper and under part of
the 'tray.' The structure will then float in water. This, however, is
not all that you want, as your centre piece must always be entirely
immersed. First bore a few holes in the tray, then fix a pretty shell,
with a hole in it, to the base of the lower 'cup,' and also form a loop
of gutta percha, from which to suspend, by means of a piece of silk, a
fragment of stone or marble of sufficient bulk to balance the centre
piece, and sink it an inch or two below the surface of the water.
At the centre of the upper cup fasten a small piece of gutta percha
tube, at the end of which the valve of a Pecten may be attached as an
ornament. The whole structure must be gently warmed and entirely coated
with fine sand; then tastefully decorated with shells and fronds of
green Ulva, and the crimson Delesseria Sanguinea.
Sometimes I introduce a globe of glass as a buoy, and to its centre
attach the tray of gutta percha.
A useful centre piece, a specimen of which I have had in use for
several months, may be formed thus. Make a tripod of gutta percha, on
the top of which attach the valve of a Pecten. From the centre of this
object fix a branch of coral by aid of gutta percha, in such a way that
it rises above the water in the tank. From under the shell pieces of
coral may be made to branch out in various directions. The stand should
be coated either with crushed shells or sand, to give it an ornamental
appearance.
It is often a source of annoyance to find the base of the aquarium so
thickly covered with dirt, &c. To get rid of this great 'eye sore,'
without emptying and re-arranging the tank, I call in the aid of a very
simple and effective instrument. By its application all objectionable
matter may be gradually removed without in the slightest degree
disturbing the water, or materially displacing the objects situated at
the base of the vessel.
The instrument mentioned is composed of a gutta percha globe, made in
the manner previously described, into one end of which is inserted
a tube of gutta percha or glass about four inches long, and at the
opposite end of the ball is introduced a second tube about eight inches
in length.
To use this instrument, close the orifice of the longest tube, and
plunge it into the water over any spot where the debris is collected,
then by removing your finger from the end of the tube, _the impurity
will be instantly sucked up into the ball_. By again placing the finger
in its former position, the siphon may be lifted out of the tank, and
its contents allowed to run off into a jug or basin placed near for the
purpose.
This operation must be repeated until the whole of the offending
particles are removed. Of course, more water will be drawn off than is
necessary, but it can easily be poured back into the tank as soon as
the sediment has been fully precipitated.
Aquaria are generally much more difficult to keep in order in summer
than in winter, owing to the rapid and profuse growth of minute
vegetation which renders the water opaque and exceedingly unpleasant to
the eye.
This ugly opacity I at one time attributed to decaying animal matter,
for I could scarcely believe that the mere increase of the algæ spores
could produce such a vile effect. Experience, however, has proved that
the latter was in reality the true cause. I tried often by syringing
the water, or drawing it off by means of the siphon, or stirring it
about in all manner of ways, to remove the objectionable muddiness,
but always without success. Limpets and Periwinkles seemed quite
useless. Nor did shutting out the rays of light for a few days have any
perceptible effect in subduing the growth of the algæ which collected
with wondrous rapidity, and arrayed each stone, shell, pebble, and even
the poor crabs, in a greenish garb.
I was therefore under the necessity, on several occasions, of renewing
the water, and considering that my residence was several miles from the
sea-coast, this task was by no means a pleasant one. What made matters
still more provoking, was the fact that the rejected fluid seemed
perfectly free from all offensive smell. I now adopt the following
novel method for removing the opacity of the water, without the latter
being changed, and also for preventing the too abundant growth of the
algæ at all seasons.
The plan in question (which requires, as already shown, to be carried
out with extreme caution by the inexperienced aquarianist) is merely to
dilute a small quantity of _alum_ in a wine-glass full of water, and
then mix it with the water contained in the aquarium. A pellet of alum
about the size of a pea is sufficient for the purpose, if the tank be
of moderate size. And if inserted on the first appearance of dimness
in the water, much future trouble will be saved.
Supposing the water to have become opaque, proceed thus--Draw off a
portion into a large jug, and mix with it the diluted acid as before
stated, then let the jug remain undisturbed for about twelve hours. The
vegetation having been deposited in flakes at the base of the vessel,
the water should then be gently strained off through a piece of fine
muslin into a second receptacle, which, in its turn, should be allowed
to stand for some time, and the contents again strained as before. This
process it is advisable to repeat several times, until the whole of the
fluid in the tank has been thoroughly cleansed from impurity.
Should the water be returned too early, an unpleasant fur coating will
appear over the entire base of the tank. This can be easily removed by
means of the siphon. Let one end of this instrument, when in action,
be passed gradually over the lower portion of the vase, and in the
course of a few minutes every sign of 'fur' will be obliterated with
the loss of but a small portion of water. When once the fluid has been
clarified in the manner here mentioned, there is little fear of the
young aquarianist being again troubled in like manner for many months,
the acid apparently preventing the algæ from being reproduced to any
such excess as hitherto.
GLOSSARY OF SCIENTIFIC TERMS.
Extracted principally from Professor Owen's learned work entitled,
"Lectures on the Comparative Anatomy and Physiology of the Invertebrate
Animals."
=Ambulacra= (L. _ambulacrum_, an avenue, or place for walking).
The perforated series of plates in the shell of the Sea-star, or
Sea-urchin, through which the sucking-feet are protruded.
=Acalepha= (Gr. _akalephe_, a nettle). The class of radiated animals
with soft skins which have the power of stinging like a nettle.
Commonly called Sea-nettles or Jelly-fish.
=Actinæ= (Gr. _aktin_, a ray). The genus of Polypes which have many
arms radiating from around the mouth.
=Alternate generation.= That modification of generation in which
the young do not resemble the parent, but the grandparent; so that
the successive series of individuals seem to represent two species,
alternately reproduced, in which also parthenogenesis alternates with
the ordinary engendering by impregnation.
=Algæ= (sea-weeds). A large class of cryptogamic plants inhabiting salt
and fresh water.
=Anomoura= (Gr. _anomos_, irregular, and _oura_, a tail). A section
of crustaceous animals distinguished like the Hermit crabs, by the
irregular form of the tails.
=Annelid.= The Anglicised singular of _annelleta_.
=Adductor muscles=, are those which hold together the shell of a
bivalve, such as the Oyster, Mussel, &c.
=Animalcules.= Those extremely small animals which are invisible to the
naked eye.
=Antenna= (from the Latin for yard-arm). Applied to the jointed feelers
or horns upon the head of insects and crustacea.
=Balanoids= (Gr. _balanos_, an acorn). A family of Sessile cirripeds,
the shells of which are commonly called Acorn-shells.
=Bivalve.= When a shell consists of two parts, closing like a double
door. The mollusca so protected are commonly called bivalves, as the
Mussel.
=Brachyura= (Gr. _brachus_, short; _oura_, tail). The tribe of
crustacea with short tails, as the Crabs.
=Branchiæ= The gills or respiratory organs which extract the oxygen
from air contained in water, as in fishes and other aquatic animals.
=Buccal= (L. _bucca_, mouth). Belonging to the mouth.
=Byssus= (Gr. _byssos_, fine flax). A term applied to the silken
filaments or 'beard' of the Mussel and Pinna.
=Carapace.= The upper shell of the Crab, &c.
=Calcareous.= Composed more or less of lime.
=Carnivorous= (L. _caro_, flesh; _voro_, I devour). The animals which
feed on flesh.
=Caudal= (L. _cauda_, the tail). Belonging to the tail.
=Cephalópoda= (Gr. _kephale_, a head; _pous_, a foot). The class of
Molluscous animals in which long prehensile processes, or feet, project
from the head, as in the Cuttle-fish.
=Ciliogrades= (L. _cilium_, an eyelash; _gradior_, I walk). The order
of the _acalephæ_ (as the Beröe) which swims by action of cilia.
=Cilia= (L. _cilium_, an eyelash). The microscopic hair-like bodies
which cause, by their vibratile action, currents in the contiguous
fluid, or a motion of the body to which they are attached.
=Cirri= (L. _cirrus_, a curl). The curled filamentary appendages, as at
the feet of the Barnacles.
=Cirripedes=, or =Cirripedia= (L. _cirrus_, a curl; _pes_, a foot).
A class of articulate animals having curled, jointed feet; sometimes
written Cirrhipedia and Cirrhopoda.
=Conchifera= (L. _concha_, a shell; _fero_, I bear). Shell-fish;
usually restricted to those with bivalve shells.
=Comminuted.= Broken or ground down into small pieces.
=Conchology.= The department of science which treats of shells.
=Convoluted= (L. _convolutus_). Rolled together.
=Cornea= (L. _corneus_, horny). The transparent horny membrane in front
of the eye.
=Crinoid= (Gr. _krinon_, a lily; _eidos_, a discourse). A family of
Star-fishes which bear some resemblance to the form of a lily. The
fossils called Stone-lilies, or Encrinites, are examples.
=Crustacea= (L. _crusta_, a crust). The class of articulate animals
(which includes the Crab, Lobster, &c.) with a hard skin or crust,
which they cast periodically.
=Decapoda= (Gr. _deca_, ten; _pous_, a foot). The crustaceous and
molluscous animals, which have ten feet, such as the Crab, Cray-fish,
&c.
=Digitate= (L. _digitus_, a finger). When a part supports processes
like fingers.
=Effete.= Barren, worn out.
=Elytra= (Gr. _elytron_, a sheath). The sheath or wing covers of
coleopterous insects (Beetles).
=Entomostraca= (Gr. _entoma_, insects; _ostracon_, a shell). The order
of small crustaceans, many of which are enclosed in an integument like
a bivalve shell.
=Entomology= (Gr. _entoma_, insects; _logos_, a discourse). The branch
of science treating of insects.
=Exuvium=, Pl. =exuviæ= (L. _exuo_, I cast off). The shell or skin of
an animal which is shed in moulting.
=Epizoa= (Gr. _epi_, upon; _zoon_, an animal). The class of low
organized parasitic crustaceans which live upon other animals.
=Fissiparous= (L. _fissus_, divided; _pario_, I produce). The
multiplication of a species by the self-cleavage of the individual into
two parts.
=Frond= (L. _frons_, a leaf). A term applied to that part of flowerless
plants resembling true leaves.
=Fucivorous= (L. _fucus_, sea-weed; _voro_, I devour). Animals which
subsist on sea-weed.
=Flora.= The plants which belong to a country or district.
=Foliaceous= (L. _folium_, a leaf). Shaped or arranged like leaves.
=Gasteropoda= (Gr. _gaster_, stomach; _pous_, a foot). That class of
animals which (like the Snail) have the locomotive organ attached to
the under part of the body.
=Gemmiparous= (L. _gemma_, a bud; _pario_, I produce). Propagation by
the growth of the young like a bud from the parent.
=Habitat.= The locality in which an animal habitually resides.
=Hinge.= That part of a shell at which the valves cohere.
=Hyaline= (Gr. _hualos_, crystal). The pellucid substance which
determines the spontaneous fission of cells.
=Hydra= (Gr. _hudra_, a water serpent). The modern generic name of
certain fresh water polypes.
=Hydrogen= (Gr. _hydor_, water; _gemmæ_, I produce). A gas forming one
of the components of water and atmospheric air.
=Infusoria.= The class of animalcules which abound in vegetable and
animal infusions.
=Lamellibranchiata= (L. _lamella_, a plate; _branchiæ_, gills). The
class of acephalous molluscs, with gills in the form of membraneous
plates, of which the oyster and mussel are familiar examples.
=Larva= (L. _larva_, a mask). Applied to an insect in its first active
state, which is generally different from, and, as it were, masks the
ulterior form.
=Ligament=. A membrane close by the hinge which connects the valves.
=Mantle.= The external soft, contractile skin of the mollusca, which
covers the viscera and a great part of the body like a cloak.
=Macroura= (Gr. _makros_, long; _oura_, a tail). A tribe of ten-footed
crustacea (as the Lobster, Cray-fish), which have long tails.
=Medusæ.= A genus or family of soft radiated animals or Acalephæ, so
called because their organs of motion and prehension are spread out
like the snaky hair of the fabled medusa.
=Molecules.= Microscopic particles of matter.
=Mollusc--Mollusca= (L. _mollis_, soft). The primary division of the
animal kingdom. It contains most shell-fish, slugs, &c.
=Monograph= (Gr. _monos_, one; _grapho_, I write). A written
description of a single thing, or class of things.
=Multivalve= (L. _multus_, many; _valvæ_, folding doors). Shells
composed of many pieces or valves, as the Chiton.
=Nudibranchiate= (L. _nudus_, naked; _branchiæ_, gills). An order of
gasteropods, in which the gills are exposed, as the Eolis, Doris, &c.
=Oxygen.= A gas which is one of the constituent parts of water and of
atmospheric air. It is essential to animal life.
=Oviparous= (L. _ovum_, an egg; _pario_, I bring forth). The animals
which bring forth eggs.
=Operculum= (from the Latin for lid). Applied to the horny or shelly
plate which closes certain univalve shells, as the Whelk, Periwinkle,
&c.
=Papillæ= (L. _papilla_, a nipple). Soft prominences which resemble in
form the teats of animals.
=Palpi= (L. _palpo_, I touch). The organs of touch commonly called
'feelers,' developed from the lablum and maxillæ of insects.
=Pectinated= (L. _pecten_, a comb). Toothed like a comb.
=Physograde= (Gr. _physis_, air; _gradior_, I advance). The acalephes
that swim by means of air-bladders.
=Phytophagous= (Gr. _phuton_, a plant; _phago_, I eat). Plant-eating
animals.
=Pulmonigrade= (L. _pulmo_, a lung; _gradior_, I walk). The tribe of
Medusæ which swim by contraction of the respiratory disc.
=Rotifera= (L. _rota_, a wheel; _fero_, I bear). The name of a class of
infusorial animalcules, characterized by the vibratile and apparently
rotating ciliary organs upon the heads.
=Rhodospermes.= The red-coloured sea-weeds.
=Serrated= (L. _serra_, a saw). Toothed like a saw.
=Sessile.= Attached by a base.
=Silicious= (L. _silex_, a flint). Flinty.
=Setæ.= Bristles, or similar parts.
=Spicula= (L. _spiculum_, a point or dart). Fine-pointed bodies, like
needles.
=Tuberculate.= Warty, or carved with small rounded knobs.
=Testacea= (L. _testa_, a shell). Molluscs with a shelly covering, as
the Oyster, Whelk, &c.
=Univalve= (L. _unus_, one; _valvæ_, doors). A shell composed of one
calcareous piece, as the Periwinkle.
=Umbones.= The base of a shell about the hinge.
=Viviparous= (L. _vivus_, alive; _pario_, I bring forth). The animals
which bring forth their young alive. See Oviparous.
=Whorl.= The spiral turn of a shell.
=Zoology= (Gr. _zoon_, animal; _logos_, a discourse). That branch of
science that treats of the habits, structure, and classification of
animals.
=Zoologist.= One who is acquainted with the science of Zoology.
=Zoophyte= (Gr. _zoon_, an animal; _phyton_, a plant). The lowest
primary division of the animal kingdom, which includes many animals
that are fixed to the ground and have the form of plants.
INDEX.
_Animalculæ_, 37.
_Actiniæ_ (Sea anemones), 38, 47.
_mesembryanthemum_, 48, 365.
_troglodytes_, 51, 62.
_bellis_, 56.
_dianthus_, 57, 62, 154, 366.
_crassicornis_, 61, 100.
_coriacea_, 56.
_parasitica_, 66.
_explorator_, 51.
Acorn barnacles, 145.
Adductor muscle, 178, 182.
Annelids, 154, 191, 315.
_Acalephæ_, 203.
Alternation of generations, 214.
_Aphrodite aculeata_, 267.
_Aplysiæ_, 54, 309, 311.
_Aquariæ_ (on the formation of marine), 357.
_Anomoura_ (Hermit crabs), 69, 92, 130, 133.
_Asteriadæ_, 271.
Algæ, 97.
_A. ventilabrum_, 161.
Amphitrite, 162.
_Buccinum undutum_, 92.
Byssus of Mussel, 168, 170, 177, 184.
_Beröe_, 210.
_Bêches de mer_, 31.
Brittle Star-fishes, 277.
Bird's foot Sea-star, 285.
Blenny (Smooth), 71, 104, 236, 336, 341, 365.
Blenny (Viviparous), 346.
Butter fish, 347.
_Brachyura_ (crabs, &c.), 69, 133.
Buckie, 93.
Barnacles, 98, 146.
Barnacle geese, 150.
Boring Acephaia, 251.
Bivalves, 122, 167, 282, 363.
Bearded rockling, 346.
_Cilia_, 35, 147, 214.
_Coryne_, 41.
Crabs, 67.
_Cancer Pagurus_ (Edible crab), 67, 69, 128.
_Carcinus mænas_ (Common Shore crab), 67, 78, 120, 127, 167, 239.
Common Whelk, 94.
Common Cockle, 84, 106, 239.
Cray fish, 128, 131.
_Crangon vulgaris_ (Common Shrimp), 139.
_Cestum veneris_, 209.
_Cydippe pileus_, 210.
_Cyanea capillata_, 218.
_Comatula rosacea_, 275.
Crinoid Star fishes, 275.
Cross fish, 280.
Cushion stars, 285.
Cake Urchin, 300.
_Chondrus crispus_ (Irish moss), 101, 123.
_Cirri_, 147.
_Cetacea_, 205.
Chiton, 226.
_C. offinalis_, 285.
_Ciliograde acalephæ_, 209.
Common Sea cucumber, 305.
Doris, 223, 363.
Doris (Spawn of), 226.
Diminutive Sucker-fish, 350.
_Decapoda_ (ten-footed crustacea), 69, 85, 115.
_D. sanguinea_, 78, 118, 368.
Dorsibranchiate annelidans, 155.
Devil's hand, 279.
Dulse, 310.
Exuviation of Crabs, &c., 85, 113, 120, 132.
Exuviation of Prawns, &c., 139.
Exuviation of Barnacles, 147.
_Eolis_, 223.
_Eolis_, (Spawn of) 228.
_papillosa_, 228.
_Echinus_, 291.
_sphæra_, 297.
Entomology, 28.
Egg Urchin, 297.
_Foraminifera_, 24, 30.
Fan-amphitrite, 161, 163.
Fishes 329.
Five-fingers (Star-fish), 281.
Gulf stream, 206.
Girdle of Venus, 209.
Green-pea urchin, 299.
Gunnel-fish, 346.
Goby (one-spotted), 309, 348.
Goby (two-spotted), 348.
_Gasterosteus aculeatus_, 352.
Golden willow, 87.
_Hyas araneus_, 80.
Hermit crabs, 94, 105, 108, 130.
_Hydra tuba_, 213.
_Hydra gelatinosa_, 213.
Hyaline stylet, 239.
_Holothuriadæ_, 303.
_Infusoria_, 33, 43, 227.
_Iridea edulis_, 74, 236.
Irish Moss, 101.
Jelly fish, 203.
_Kerona silurus_, 35.
_Lepas anatifera_ (Ship barnacle), 148, 150.
Laminated nereis, 155.
_Luidia fragillissima_, 285.
_Lepus marinus_, 309.
Lettuce Ulva, 180, 364.
Limpet, 81, 98.
Lobster crabs, 94.
Lily stars, 271.
Lobster (The), 131, 290.
_L. digitata_ (Oar weed), 277.
Lingthorn, 285.
Lump sucker, 347.
_Maia squinado_ (Spider crab), 79, 80, 82, 167.
Mussel (_Mytilus edulis_), 82, 122, 167, 363.
_Medusæ_, 203, 210, 216.
_Modera formosa_, 217.
Montague Sucker-fish, 349.
Marine Aquariæ, 357.
_Macroura_ (as Lobsters), &c.
_Nereis_, 155, 158.
Nudibranchiate gasteropoda, 226.
_Ostrea edulis_ (oyster), 81.
_Ophiuræ_, 277.
_texturata_, 277.
_albida_, 277.
_Ophiocoma rosula_, 279.
_Paramecium caudatum_, 35.
_Portunus puber_ (Velvet crab), 68.
_Porcellana longicornis_ (Minute Porcelain crab), 79.
Periwinkle, 95.
_Pagurus bernardhus_ (Hermit crab), 96, 108, 146.
Pecten, 108, 370.
Prawn, Common (_Palæmon squilla_), 137.
_Phyllodoce laminosa_, 155.
_Purpura lapillus_ (Whelk), 103, 168.
Portuguese man-of-war, 212.
Pholas (_crispata_), 84, 153, 236, 245, 258, 365.
Pholas (_dactylus_), 260.
_Pentacrinus Europæus_, 275.
_Psolus phantapus_, 304.
Pike-fish, 339.
_Pinnotheres pisum_ (Common Pea-crab), 82.
Pinna, 83.
Partane, The (Edible crab), 65, 124.
_Pulmonigrade acalephæ_, 21l.
_Physograde acalephæ_, 211.
_Parthenogenesis_, 218.
_Rotifera_, or Wheel-bearers, 36.
Rosy Feather star, 276.
Rosy Heart urchin, 300.
Rockling (Five-bearded), 347.
Razor-fish, 323.
Stickleback, 25, 108, 352.
_Sertularia_, 41.
Ship Barnacle, 145.
Sea-Mouse, 267.
Star fishes, 273.
_Solaster papposa_, 167, 286.
_endeca_, 286.
Sea Urchins, 289.
Silky Spined urchin, 299.
Sea Cucumbers, 303.
Sea Hares, 309.
_Serpulæ_, 315.
_Sabellæ_,315, 319.
_Solen siliqua_, Razor-fish, 324.
Soldier crabs, 92.
Shrimps, 137.
_Saxicavæ_, 248.
Sucker fishes, 348.
Shore crab, 65, 68, 72, 120, 235.
Swimming crab, 66.
Spider crab, 78.
_Salex vitellina_ (golden willow), 87.
Silver Willie (_T. zizziphanus_), 191.
_Terebella figulus_ (the potter), 191, 195.
_littoralis_, 197.
Trepang, 304.
Top-shell, 132.
_Trochus_, 146.
Tubiculous annelids, 162, 194.
Tanks, 355.
_Uraster rubens_, 167, 281.
_Ulva latissima_, 98, 180, 367, 368.
Univalves, 94.
Urchins (Sea), 298.
_Vorticellæ_, 35, 38.
Velvet Fiddler crab, 66, 74.
Whelk (_Purpura lapillus_), 168.
_Zoothamnium spirale_, 43.
_Zooids_, 219.
Zoophytes, 47, 49.
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MARTIN RATTLER; or, A Boy's Adventures in the Forests of Brazil.
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THE CORAL ISLAND: A Tale of the Pacific. With 8 Oil-Colour Engravings.
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HUDSON'S BAY; or, Life in the Wilds of North America. Post 8vo, cloth.
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"Mr. Ballantyne has already conducted his young readers through the
Fur Regions of the Far North, besides relating tales of the Esquimaux
and the Pacific Islanders. He may, therefore, be counted among winter
favourites, for his books come with the redbreast, and are equally
cheerful. His Martin Rattler begins life as an unruly fellow, but
improves as he grows older, especially when he gets among the Brazilian
forests--all desolation and beauty. There he learns ever so much of
natural history--as the readers of his adventures may also do if they
please--and witnesses some remarkably curious scenes, which, if not
warranted by reference to Humboldt, are at least described in minute
detail by Mr. Ballantyne, who is always cheerful, entertaining, and
instructive."--_Athenæum._
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TRANSCRIBER'S NOTE:
Obvious printer errors have been corrected. Otherwise, the author's
original spelling, punctuation and hyphenation have been left intact.
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