By
Grant Allen
From
Longman’s Magazine, July 1896.
Digitized
by Doug Frizzle, Feb. 2017.
IT
was, you will remember, the erroneous opinion of Alice (in Wonderland) that
whiting were fish with their tails in their mouths. That biological mistake was
a natural result of the culinary or purely domestic conception of animal life.
In like manner, I believe, a great many people are still of opinion that
lobsters are habitually and normally red—which is a rudimentary blunder of the
same character as if one were to suppose that chickens swam in a sea of onion
sauce as their native element, or that turkeys were infested with parasitic
truffles. To combat such insufficient notions of crustacean life in the shallow
seas it may be well to attend a lobster At Home off the coasts of Britain.
The common lobster who receives
you in his rocky house is a ten-legged crustacean, with a large,
powerful, and very muscular tail. This tail it is which marks off most
distinctly the lobster group (including the crayfish, prawn, and shrimp) from
their degenerate relations the mere crawling crabs, which are practically
tailless. The difference in shape, again, is ultimately dependent upon a profound
difference of habit and manner. All the lobster kind are more or less of
swimmers, and they use their powerful tail with immense effect for jumping or
darting through the water when disturbed, as well as for a gentler method of
propulsion by fin-like flappers, to which I shall recur a little later. They
may be regarded, in fact, from the point of view of habit, as great marine
fleas; and this power of jumping or bounding through the sea is their most
marked characteristic. The crabs, on the other hand, do not leap or swim in the
adult condition; they merely crawl with a rather awkward motion along the
bottom. Hence they have walking legs more developed than the lobster’s; their
body is round, flat, and compressed; but the little shrivelled tail, reduced in
their case to a bare shrunken relic, is doubled up under the body so
inconspicuously that it probably altogether escapes the notice of the purely
culinary or Epicurean observer. Both groups are descended from a common
ancestor; but the crabs have taken so exclusively to walking that their tails
have atrophied till they are reduced at last to mere sheaths for the eggs and
other reproductive organs; while the lobsters and prawns have taken to jumping
freely on the open, and used their tails so much that these leaping organs have
at last developed into the largest and most important part of the animal.
Our English lobster is a
beautiful, glossy, bluish-black creature, of iridescent sheen, with a scheme of
colour not remotely reminding one of the mingled hues on the back of the
swallow. Even when taken from the water his melting tints are very remarkable:
but when seen at home, among his rocky haunts, and with the glaucous green glow
of the sea shed lustrously over him, he is as magnificent a creature of his
sort as nature has developed. When boiled, indeed, he turns at once to the
vulgar and uniform red of the British soldier; but in his native state he is
subtly and indescribably mottled with patches of dark blue and of cloudy black,
which merge by imperceptible degrees into one another. Looked down upon through
the water from above, he is seen among the crags as a black lurking mass, just
projecting from a tunnel or crevice of the serpentine stacks, which he fits to
a shade; whilst his front claws or crushers, his head and stalked eyes, and his
tremulous antennae alone stand out on the watch for prey beyond the general
surface of his sheltering rock-wall. But beheld on the level, as one sees him
in the aquarium (which is, of course, the only fair way to judge the charms of
submerged animals), he becomes at once a far more imposing creature. His hues
are then even more vivid than those of the burnished swallow’s back; and his
great black eyes gleam out from his lair with the watchful intelligence of the
patient hunter.
Your lobster is an athlete of no
small pretensions. He has three distinct modes of progression, and at least
three sets of locomotive organs adapted to them. He walks or crawls on the sea
bottom; he swims on the open; and he darts or jumps backward with his powerful
tail muscles. Each of these modes requires at our hands a separate
consideration.
The lobster’s legs, all told, are
ten in number. But only eight of these are largely used for walking. The front
pair, or big claws, have been specialised, as in the crab and most others of
the higher crustaceans, into prehensile organs for catching and crushing the
prey. Their use is obvious. Lobsters feed largely off mollusks of various
sorts, and other hard-shelled marine animals; in order to be able to break or
crush the shells of these, and so get at the softer flesh within, they have
acquired such large and very muscular nippers or pincers. That is not all,
however; not only have the two front legs been differentiated and specialised
from the eight others in this manner, but also, by a rare exception to the
symmetry of the body, the right claw has been specialised from the left, each
being intended to perform a distinct function. One is a scissors; the other is
a mill: one is a cutter; the other is a cracker. As a rule the right claw is
the slenderer and longer; it has tooth-like projections or serrated edges on
its two nipping faces, and it is rather adapted for biting and severing than
for crushing or grinding. The left claw, on the other hand, is usually thicker,
heavier, and rounder; its muscles are more powerful; and in place of sharp
teeth it has blunt tubercles or hammers of different sizes; it acts, in fact,
more like a nut-cracker than like teeth or a saw; it is a smashing organ.
Nevertheless you will find it interesting to observe, by noting the lobsters
served to you at table, that this differentiation has hardly as yet become
quite constant; for sometimes it is the right claw that displays the
hammer-like nut-cracker type, and the left that acts as nipper and biter; while
sometimes no difference occurs at all, both claws alike being sharp-toothed or
blunt-hammered in the same specimen.
Behind these two specialised
forelegs or claws, which are really connected with the mouth and the capture of
food rather than with the process of locomotion, come the eight true legs,
employed in walking. On shore, indeed, or as you see the lobster lie on the
smooth flat slab of a fishmonger’s shop, these legs are truly but feeble members.
At home in the salt water, however, for which, of course, they are primarily
adapted, they present a very different appearance. The buoyant medium supports
and floats the heavy body and claws, and the animal moves along on the tips of
his eight feet with a peculiarly graceful gliding motion. He hardly walks: he
seems rather to slip through the yielding water. His nimbleness under such
circumstances surprises those who think of him only as a weighty and
armour-clad creature, forgetting that in his own atmosphere (if I may venture
on the phrase) he is buoyed and upheld by the sea that surrounds him on every
side. When walking on the bottom in this way, in search of prey, he extends his
big front claws obliquely before him, so as to offer the least possible resistance
to the mass of water; six of his legs he uses as true legs alone; the last pair
of all he employs rather as picks or stilts, if I may use such a metaphor,
pushing them firmly into the sand or pebbles on the bottom, and steadying by
their aid his forward motion.
The second set of locomotive
organs are the swimmerets, or fin-like appendages under the animal’s tail, each
of which acts as an oar or paddle. They consist of a short stalk or handle,
fitted with two flat wide blades. When the lobster walks on the bottom, he
extends his tail unfolded behind him, and gently waves these swimmerets like a
fish’s fins to assist and guide his forward movement. They thus play the part
at once of oar and rudder, though the latter function is still more efficiently
performed by the expanded organs which terminate the tail. But the lobster can
also use the swimmerets to swim with alone, independently of the crawling or
creeping legs; and though this motion is but slow and slight it has a
peculiarly graceful and mysterious appearance. A swimming lobster seems to
glide through space with fairy elegance. As a rule, however, the lobster sticks
to the bottom, and only swims obliquely downward for very short distances from
its home in the rock to the sands beneath it. Nor is this the only function of
the swimmerets. Nature, we all know, is economical of organs; and therefore we
need not be surprised to learn that in the female lobster the swimmerets are
further utilised to serve as supports for the eggs, or ‘berry,’ in a way which
will arrest our attention a little later.
And now we come to the third and
by far the most powerful organ of locomotion in the lobster, the large and very
muscular tail. Strange to say, however, this organ acts in the opposite
direction from the other two; by its aid the animal is able to spring rapidly,
not forward, but backward. Why backward? Well, the tail is
not used as an ordinary means of locomotion at all, but is reserved for
purposes of sudden retreat and defensive action. As the lobster walks about
over the hunting-grounds near his lair (for of course he has preserves of his
own around his estate), he keeps his long antennae, or feelers, constantly
waving up and down before him, so as to give him warning of the approach of a
dainty morsel or a stronger enemy. On these rather than on his imperfect
stalked eyes he seems to rely most for information and for danger signals. If
the offending object be not big enough or active enough to frighten him, he
stands up menacingly on his walking legs and puts himself in the exact attitude
of a boxer. One large claw he holds for defence in front of his head; with the
other he strikes out against the hostile object, and strives to crush or kill
it. Fishermen sometimes draw lobsters from their holes by presenting them in
this way with a blade of an oar; the unsuspicious crustacean seizes it with
his claw and refuses to let go, sometimes even permitting himself through pure
obstinacy to be drawn out of the water. But when the enemy is one of whom the
lobster is afraid he retreats precipitately by bending his big tail with a
spasmodic jerk, which drives him backwards through the water at the rate of
twenty-five feet in a second. In clear water you can see them dart past like
lightning when disturbed or terrified. In this peculiar backward jump the
animal is also largely aided by the fan-shaped, rudder-like organs at the end
of the tail.
As a rule, when thus alarmed, the
lobster darts away backward into deeper water, where he is not likely to hurt
himself by knocking against hard foreign bodies. But he has also no small
delicacy of adjustment in this matter of jumping, and if near his own home—for
every lobster has a recognised house of his own in some cranny of the rocks—he
will fling himself into it backward with an accuracy of aim like that of a
swallow or sand martin swooping down upon its nest from a considerable
distance. The tail is thus an organ of defensive retreat, and its large size is
the index of its use to its possessor.
It may be interesting to the
culinary naturalist to observe in passing that this distribution of the
locomotive organs is mainly answerable for the varieties and disposition in the
flesh of the lobster. The large crushing claws, constantly used in feeding,
have firm but not hard or stringy flesh, and are much more digestible than the
other portions. The small walking legs, having relatively little work to do, are
supplied with smaller muscles, distributed in an intricate and peculiar
network of thin shelly material. But the big and powerful tail, employed for
the violent act of leaping, and constantly exerted in the state of nature, has
correspondingly hard and strong muscles, which form the mass of the edible
portion, but are relatively indigestible through their closeness and toughness.
In the crab, on the other hand, which merely crawls, we eat mainly the claws
and the lesser leg-muscles.
Lobsters are essentially
nocturnal animals, lurking for the most part in their holes during the day, and
coming out to feed on the sands by night. It is for this reason, no doubt, that
they depend so little upon their imperfect eyes, all the more so as they
inhabit a depth of water where light becomes of very slight importance. On the
other hand, it is probable that the antennae end in organs of smell of a
delicately discriminative sort, and that by their aid the lobster knows friend
from foe and food-stuff from enemy.
Our crustacean not only roams the
sea bottom in search of food, but also digs and burrows in the sand and mud,
like a maritime mole, in pursuit of shell-fish. These he catches and crushes
with his hammer-like claw, extracting the soft parts to eat at leisure. But he
is also an angler after fish, which form, perhaps, the chief portion of his
diet; and he preys to a great extent upon his cousins the crabs, whose thinner
shells and more exposed habits make them an easy booty. In aquariums lobsters
also clearly display cannibal habits; if one lobster loses a claw his
neighbours unanimously turn and rend him. That this evil habit exists still
more abundantly in the native state we have unfortunately more than ample
evidence, for in the stomachs of old specimens the shells of their juniors and
even of hen lobsters have been frequently recognised. Such ungallant conduct
almost seems to justify the extreme sentence of boiling alive, to which
lobsters caught by man are usually subjected. As to the question whether their prey
is living or dead, lobsters are far from particular. All is fish that comes to
their net. They rank, in fact, among the chief scavengers of the sea, and
though they habitually catch and eat living animals they do not despise dead
and decaying specimens. They are at once the tigers and the hyenas of their
world; they double the parts of the eagle and the vulture.
The early history of the lobster
is full of interest. He undergoes in his infancy a series of metamorphoses at
least as curious, as varied, and as instructive as those of the frog and the
butterfly. The eggs, which are deep semi-transparent green in the living
animal, not bright red, as we see them when boiled, are laid in early autumn.
But the careful mother does not turn her offspring loose at once on a cold and
unfeeling world; she fastens the ‘berry’ sedulously to her own swimmerets, by
means of gummy adhesive threads, and carries it about on her journeys for
several months thus closely attached to her own person. Meanwhile the motion of
the swimmerets assists in aerating the eggs and promoting maturation. By June
or July of the succeeding summer the young fry are hatched out, being rather
less than half an inch long at the moment of escape from the leathery
egg-shell. The hen lobster lays from 2,000 to 12,000 of these little round
eggs; but out of that large family only about 1,000 usually hatch out, while
not more than three or four of the whole brood in all probability ever arrive
at maturity. The rest are killed by natural causes in infancy, or devoured by
their own kind and other enemies.
And here we get a measure of the
ferocious cannibalism which, I grieve to say, prevails among our subjects.
Young crayfish, first cousins of the lobsters, have hooked forceps claws, as
Huxley pointed out, by means of which they cling, after hatching, in little
colonies to their mother’s swimmerets. Thus the maternal crayfish crawls about
her native stream, like the kangaroo, carrying her young ones with her; while
the baby crayfish, good brothers and sisters, derive shelter and food from this
motherly solicitude. But the bloodthirsty young lobsters, as soon as hatched,
instantly disperse themselves with a sort of natural repulsion, after the
curious fashion of a brood of baby spiders, and for the selfsame reason. As Dr.
Herrick, the author of a learned and exhaustive work on the American lobster (a
species which differs but little from our own), rightly remarks, ‘a swarming or
gregarious habit would be fatal to this creature, on account of its inborn
pugnacity and cannibalism.’ The family disperses to avoid being eaten by its
unnatural brothers.
Our young lobster, once more,
emerges from the egg not lobster-like in form, but as a lobster tadpole or
larva. In this its earlier avatar it is an active, free-swimming pelagic
creature, not unlike, in general look at a first rough glance, to the familiar
mosquito larva—with which, of course, I need hardly say it has no real
affinity. Its early history, which has only of late been traced in detail, is
far too varied and minute for popular apprehension; it must suffice to say
that the baby lobster swims openly on the surface of the water, and undergoes
several moults, each accompanied by marked changes of structure and appearance,
before attaining its adult form and its final walking and leaping habits. In
the earliest stage our larva is quite transparent, about half an inch long, and
possessed of grotesquely big eyes, such as befit a free-swimming,
surface-haunting animal; at this level it nearly approaches a much lower and
presumably ancestral form of crustacean development. Very young lobsters
subsist mainly upon killing and eating one another, which
is the survival of the fittest reduced to its simplest and most naked terms.
The family utilises its less active members for the
development of the more powerful. At each moult, however, the animal grows more
and more lobster-like in shape, while recapitulating, as it seems, the various
stages in the evolution of its kind from a very primitive crustacean
progenitor. During all this time our larvae are diurnal not nocturnal in habit;
they therefore depend more largely upon sight than upon smell as the leader
among the senses.
Even when the young lobster
reaches the full lobster form, however, he is still far from adult; he goes on
growing for many months, or even years. But he now quits the surface and takes
entirely to a nocturnal life on the ill-lighted sea bottom, for which his
existing locomotive organs and his adult senses are specially adapted. Still he
continues to moult or cast his outer shell— many times yearly in the very
young, once a year in the adult, less frequently still in old and thoroughly
hardened specimens. This moulting is, of course, necessitated by the very
conditions of growth themselves, for an animal encased in such a coat of solid
armour must either not grow at all or else cast off its mail and renew it
periodically. Naturally the lobster follows the last of these two plans; his
moulting is a result and accompaniment of growth.
Odd as it may sound to say so,
the animal grows before, not after, he casts his old hard shell—that is to say,
he makes new cells and tissues, which are not at once filled out, but which are
intended to plim to their full dimensions as soon as he has got rid of his
binding and confining external skeleton. When the critical moment at last
arrives, a new soft shell grows entire within the older and harder one; and the
animal then withdraws himself, leg by leg, claw by claw, and swimmeret by
swimmeret, out of the enveloping coat of mail which covers him. The shedding of
the old coat is complete and absolute; not a fragment remains; even the
apparently internal hard portions are cast off with the rest, for the entire
covering forms one continuous piece, the interior portions being really, so to
speak, folds of the skin inserted inward. An entire new skeleton has already
grown within the old one, but exceedingly soft and flexible in texture, and the
body becomes so almost fluid or jelly-like (not in structure, but in power of
compression and extension) that even the big claws are drawn out through the
narrow apertures of the joints in a perfectly marvellous manner. After a longer
or shorter period of muscular paroxysm, the soft lobster at last disengages
itself entirely from the dead shell, and emerges upon the world a new and
defenceless fleshy creature. The whole cast skeleton, unruptured in any part,
but disengaged by lifting up the body-piece where it joins the tail, looks
exactly like an entire dead lobster.
Immediately
after the moult the apparent growth takes place with extraordinary rapidity.
Recent investigators have shown that this rapid growth depends upon the
absorption of water into the blood and tissues through the soft new shell. For
at the moment when the lobster emerges from his old coat the new one is already
fully formed in every part beneath it; the skeleton needs only hardening matter
in order to solidify it into a complete suit of armour, like the old one, but
larger. So far as its living matter is concerned the lobster is now really
bigger than before; he requires just water to fill him out and lime to harden
his newer and larger shell; but when these have done their respective work he
has completed his growth till the next moulting period. He thus grows, as it were,
by fits and starts at measured intervals.
Moulting, however, is both
dangerous and expensive. Many lobsters die naturally in the process; others are
eaten up by unkindly neighbours of their own species or by foreign enemies
during their defenceless convalescence. It is commonly said by fishermen and
others that lobsters after moulting retire to their lairs, and pass through a
period of complete inactivity till their shell has hardened. This idea,
however, is probably due to the misconception that the new shell is formed
after, not before, the shedding of the old one. As a matter of fact the soft
lobster does really retire as far as possible from vulgar observation and too
curious inquiry during his softest time; but he nevertheless ventures out by
night to feed, a point rendered certain by the comparative frequency with which
soft specimens are caught round the coasts in lobster pots. But the new shell
hardens rather rapidly, partly because the lobster has providently laid by in
readiness in his body a supply of lime in easily soluble forms, and partly
because the neophyte swallows fragments of shells and other calcareous matter,
as Dr. Herrick points out, which he dissolves in his stomach and uses up in
hardening the new coat of mail. Thus in a few days the fresh shell has acquired
a leathery consistency, and by the end of six weeks it is as hard as the old
one.
Closely connected with this habit
of moulting is the still more peculiar power known as ‘recrescence’—the faculty
of reproducing lost limbs and organs. Lobsters and crabs, as we have seen, are
highly pugnacious and aggressive creatures, which fight to the death with one
another and with alien enemies; but if seized by the nipper claws they seem
instinctively to recognise, that further fighting is useless, and instead of
continuing the hopeless battle they cast off the offending limb and retreat
without it, thinking it better to lose one claw than life and freedom. Nature
provides beforehand, in fact, a definite place where such sacrifices should be
made, by making a break at the base of the leg; the ruptured surface hardly
bleeds at all, while in a short time a new claw buds forth from the severed end
and replaces the old one. The antennae and small legs also grow again when
broken off by accidental injury.
This fact of recrescence, found
also in lizards and some other animals, and common in plants, is of profound
interest in philosophical biology, as Mr. Herbert Spencer was the first to
point out; for it suggests the idea that the formative material or protoplasm
in every organism has a natural tendency to reproduce in its entirety the
native form of the original creature, much as crystals have a tendency to
precipitate from their mother liquid in certain characteristic or specific
shapes. When this ideal entire form is mutilated the common plasm rebuilds the
broken part; and Mr. Spencer struck out the luminous idea that just in the same
way the egg or germ tends to rebuild by its own internal energies the shape of
such a body as that from which it was originally derived. The mystery of birth
becomes thus to some extent a mere special case of the mystery of the
rebuilding or recrescence of the body. Assimilated matter, once taken into the
organism, has the power either of restoring that organism complete or of
forming new organisms essentially similar. This is the most pregnant hint as to
the true nature of heredity that has yet been thrown out by any biologist.
Only two other species of true
lobster beside our own are ‘known to science’—the American and the Cape
lobsters. They differ in petty details alone from the European form; the
American kind is noticeable chiefly for the much larger size of its crushing
claws, a fact which may have struck the prudent housewife in the course of
opening and currying the tinned lobster of commerce. I apologise, however, for
the obtrusion of such a fact in the present article, for I am prepared to admit
that no crustacean is really at home when boiled and potted. I think the reason
for this abnormal development of the crushing claws in the American species
must probably be sought in the generally harder nature of the solid mollusks on
which it feeds. Our English species seems to live mainly on true fish, soft
crabs, and such relatively thin-shelled mollusks as mussels, razor fish, and
cockle-like forms. But the American lobster, a great borrower after buried sand
mollusks, makes a large part of his living out of the very hard clams and other
solid-shelled mollusks of the western shore, exposed to the terrible roll of the
Atlantic waves on the exposed coasts of Maine, Massachusetts, and Nova Scotia.
He therefore needs larger and more powerful claws in order to crush these very
tough food-stuffs. Huge heaps of clam shells are often observed at the end of
the lobsters’ burrows in the West, as are the remains of our less protected
English shell-fish at the mouths of the holes frequented by our own species.
The so-called Norway lobster,
occasionally taken on the British coast, is a much more distant cousin,
belonging to a separate genus, Nephrops, with slenderer claws, well
adapted for picking food out of crannies in rocks, and is distinguished by a
somewhat more prawn-like and graceful aspect. As to the spiny lobster, or langouste, dignified by science with the imposing classical
title of Palinurus, he is still less of a relation,
more South European in type, and found in Britain only on our southern shores.
He poses as a sort of sea hedgehog, being covered all over his body with
projecting spines, and adapted rather for defence than defiance. His marked
peculiarity lies in the fact that he has no crushing claws at all, being
content with ten almost similar walking legs, the first pair of which scarcely
differ in any way from the others. In this curious form we may probably recognise
the modern representative of some primitive and less developed ancestor, little
given to attacking hard food or enemies, and therefore unprovided with fighting
or crushing members. In the more advanced lobsters, on the other hand, the
front claws have been progressively modified and specialised for this important
function. The spiny coat of Palinurus points, no doubt, in the same
direction. For animals which can fight, like the lion or the bull, do not
generally need such passive protections; it is usually skulkers and belated
relics, like the porcupine and the hedgehog, which have survived by acquiring
these unwarlike armours.
The true lobsters are thus seen
on the whole to be the princes and heads of crustacean nature. In a single
word, they are a dominant family. Where they live they rule. Few enemies can
tackle them; their most dangerous foes are those of their own household. Armed
offensively with their mighty claws, armed defensively with their impenetrable
carapace, they attack boldly, and fear or shrink from few hostile creatures.
Yet they have the power, when alarmed, of beating a rapid and effective retreat
with their muscular tails, or of leaving their claws, when necessary, behind
them. They can either carry out a strategic movement to the rear into deeper
water, or dart back with a bound to the safety of their rock shelter, where,
with body protected and only the armoured head, spiked frontlet, and huge claws
projecting, they present a terrific face to the most determined aggressor. No
creature of their size is more formidable or better armed. They represent in
our seas the highest result of natural selection in the crustacean line,
perhaps even the most splendid development of the mailed soldier type now
living on our planet. And when seen by the proper light in their native element
they are as beautiful in hue and as graceful in movement as they are wonderful
in shape and terrible in fighting.
Grant Allen.
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