The mighty deep

AMONG the multitudinous hosts of living creatures which throng the Ocean, vast hordes are furnished with some kind of protective armour, the better to take their part in the ceaseless warfare for existence.

Though the armour differs widely in different kinds of animals, they offer one and all a great contrast to the soft jelly-like Medusæ.

Starfishes and Sea-urchins, for example, are guarded by tough or hard skins, with actual plated armour and sharp prickles. Limpets are sheltered behind single firm shields, and in any moment of peril become instantly glued by suction to a rock. Oysters dwell within stout bivalve shells. Hermit-crabs carry with them empty purloined shells, of other creatures’ construction. Crabs and Lobsters wear strong suits of sheltering armour, joined together bit by bit, as knights and squires of old were clothed from head to foot in the many “pieces” of a mediæval soldier’s military suit.

The armoured hosts belong to various divisions in the Animal Kingdom,—starfishes and sea-urchins to one; limpets and oysters to another; crabs and lobsters to a third. And all three, together with microscopic jelly-specks and sponges and coral-polyps and medusæ, belong to a much greater Division, which embraces all “Invertebrate” or Backboneless creatures.

If they have not backbones and ribs, they have skeletons of a kind. Only, as a general rule, the skeletons lie outside or are visible through the transparent body, instead of being hidden away inside, as in most fishes.

The prickly-skinned starfishes and sea-urchins are familiar objects with most of us.

Both belong to a Division in the Animal Kingdom which is well above the level of jelly-fishes. Both have arms or rays, proceeding from a central disc. But in the starfish the rays are separated; in the sea-urchin they are joined together.

Starfishes and sea-urchins are able to move and even to travel, though in most cases with extreme deliberation. Both can put out little tube-feet suckers, by means of which they can change their position, and can even slowly right themselves, when turned the wrong way up.

Sometimes the sea-urchin uses its sharp spines as an additional means of getting along. And while the common starfish can seldom advance faster than at a rate of about one half-inch per minute, there is a species which flings itself forward in a more reckless and rapid style, by using its rays as limbs.

Starfish and sea-urchin are alike protected by an armour of hard little plates, arranged in neat rows upon the skin. Not plates made in a workshop, and purchased by the owner for its use, but unknowingly secreted by the animal itself; formed, like Foraminifera shells, from lime drawn out of the water.

Between these plates are tiny openings; and through those openings are put out the minute tube-feet. Even in armour made by skilled workmen for human beings, joints have always been necessary; and we know from history how many a gallant fighter in past centuries was slain by an arrow piercing where a joint allowed it to enter.

Certain members of the immense Worm Family, living in the sea, wear protective scales and bristles; but these can only be named in passing.

The great Mollusc Family is found throughout the whole Ocean, from sea to sea, from shore to shore, from the surface to the utmost depths. It includes numberless subdivisions, and enormous varieties in shape and size, in colouring and kind. It contains millions of the tiniest little fragile shells, such as those described by the poet in well-known lines:—

It contains also the giant clams of southern seas, the hugest bivalves ever seen, one pair of which may weigh five hundred pounds.

A Mollusc is usually a soft-bodied creature, with a so-called “foot,” a nervous system, a mouth, a “mantle,” and a protecting one-valve or two-valve shell.

The “mantle”—a peculiarity of this family—is a curious loose fold of the skin or wall of the body, wrapped round like a mantle. From the “mantle” is formed or secreted the hard shell, largely composed of carbonate-of-lime. In the shell itself there are no blood-vessels, there is no actual life; and it cannot grow, as the creature within it grows. Yet in a sense it grows, since by the addition of constant fresh layers to the edges it becomes larger and larger, thus accommodating itself to the increased size of its inhabitant.

Mollusc shells are of all imaginable shapes and kinds; and often they are of extraordinary beauty.

Sometimes they are thick and hard, so as to refuse the passage of light. Sometimes they are so thin as to be translucent. Sometimes they are exquisitely pearly or iridescent. The latter effect, seen in the mother-of-pearl lining of oyster shells, is due to enormous numbers of most fine and delicate lines, close together, which reflect and break up the rays of sunlight, much after the manner of a prism.

Perhaps in the whole Mollusc Family none of the members are so interesting to man as the oyster—partly as a much-relished food, partly as the manufacturer of pearls.

Among gems worn by women few are fairer, none more emblematic of purity and grace, than these. Yet, so far as relates to any intention on the part of the oyster, any idea of forming that which is lovely and valuable, no thanks whatever are due to the producer.

An oyster makes pearls simply for its own convenience. As in the case of other bivalves, if any foreign substance happens to get inside the shell, and cannot be pushed out, it is straightway covered over, and thereby rendered harmless. Sometimes the intruder is a grain of sand, sometimes a parasite. Oftener yet, it is an oyster-egg which has proved a failure. In any event, the oyster promptly clothes it in that beautiful material—pearl—which it secretes by nature, and because it cannot do otherwise.

We know well enough the ordinary size of “edible” oysters. The pearl-forming relatives are often much larger, having shells from eight to twelve inches in diameter.

One does not commonly associate the idea of Mind with a Limpet. Yet it appears that even limpets are not without the organ of locality.

Human beings, brilliant in other respects, are sometimes woefully deficient in this quality. But a limpet knows what he is about as to the geography of his own locality. He chooses his resting-place with care, much preferring a smooth rock-surface to one that is broken or dented. Then he clings fast, and the shell in its growth is studiously adjusted to the outlines of that selected surface. When the limpet “excursionises” in search of sea-weeds, vegetables being a needful part of his diet, it is remarkable that he returns to the same spot. Evidently he prefers his own home to new quarters.

These lower Molluscs have to be passed over quickly. A whole volume might be filled in merely indicating the different species and varieties of them.

At the top of the Mollusc ladder, cousin to limpets, whelks, oysters, clams, and shell-fish innumerable, but in status far above them all, we find the powerful Cuttlefish. A “fish” in popular language; yet no fish truly, but a very highly developed Mollusc.

“Cephalopod” or “Head-footed” is the distinguishing name for this sub-class of Molluscs.

Very unpleasant creatures they are to tackle—more particularly those described by the familiar titles of “Octopus,” “Squid,” and “Devil-fish.” More particularly too when an individual of large dimensions has to be reckoned with.

The species that make their home near British shores seldom reach any great size. They cannot for a moment be compared with the great creatures of warmer climes; still less with the monsters of Ocean’s depths. Yet it is not desirable to have a hand or a foot in their tenacious grip.

Most of us have seen small specimens in an aquarium—evil-looking at the best. Sometimes individuals of the large species visit us from a distance, though they probably do not take up their abode by choice in our neighbourhood.

The body of a cuttlefish, like the bodies of most Molluscs, is enwrapped in a loose mantle, which in this instance is of strong and muscular make, perpetually enlarging and contracting. From the one opening in the mantle emerges the head, with two large eyes and a mouth; and round the latter, which generally boasts a sharp beak like that of a parrot, spring eight or ten long lissom powerful “arms” or limb-like tentacles, each furnished with a row of suckers, which in the smaller kinds look rather like buttons.

Through the opening at its neck the creature draws in and pours out water—breathes it in and out, in fact. When in repose, this breathing goes on quietly and automatically. But if the animal wishes to move, it forces the water out in a violent spurt through what is called the “siphon,” always in a direction opposite to that in which it intends to go. So great is the force thus employed that the cuttlefish rushes with wonderful speed, often with lightning-like rapidity, through the water.

While not protected by outside armour, like limpets and oysters, it really does secrete a shell; but the shell is inside instead of outside the mantle, stiffening the latter, though not protecting it from injury. In its case, however, the weapons of offence are sufficient, and there is less need for defensive armour.

In the cuttlefish we have a very tiger of the ocean, haunting vast areas in numbers which cannot be calculated.

One or two kinds are known which prefer to live solitary lives, but usually they herd together. Woe betide all weaker creatures where they abound! Once caught in those powerful arms, within reach of the fierce beak, no chance for them remains. Molluscs, crabs, fishes, all alike fall victims to this ruthless destroyer. It is said that the cuttlefish, like its striped prototype on land, will kill when not hungry for the pure pleasure of killing.

The smaller species are a principal article in the diet of dolphins and of codfishes. But the giants of the race would be in all cases too much for these puny foes.

Even a Bengal tiger, however, may be mastered by an elephant; and the mightiest of squids has to succumb before the yet mightier sperm whale.

“The monsters vast of ages past” received attention in a well-known poem. But the monsters vast of ocean-depths in the present may surely compete with them. Happily for mankind, these awful creatures do not frequently come out of their “ocean-caves” to be interviewed.

Now and again one is caught, or is flung ashore by a storm, or its dead remains are found and examined.

One huge creature, captured near Labrador, was reported to have a body thirteen feet long, with arms reaching to a distance from the head of thirty-seven feet. Another, left by the retreating tide on a Newfoundland beach, had a body twenty feet long, and arms about the same in length as those last mentioned.

But no more striking description has been given than that of Mr. Frank Bullen, in his fascinating volume,[6] when he tells of the tremendous midnight conflict between a large sperm whale and, surely, the monarch of the squids, “almost as large as himself, whose interminable tentacles seemed to embrace the whole of his great body.” The whale’s head “seemed a perfect network of writhing arms,” and by its side “appeared the head of the great squid, as awful an object as one could well imagine even in a fevered dream, with immense black eyes, at least a foot in diameter.” As the “titanic struggle went on,” the whale, “in a business-like methodical way,” munched at his huge enemy, gradually overcoming its resistance.

Such a battle-royal as this is perhaps very seldom to be seen, even by those who spend their lives upon the sea. It may be that these terrible creatures rarely come to the surface, unless compelled to do so by a hungry whale.

What they must be to the denizens of the deep, ever watching for prey, or pursuing it with swift determination in the darkness—“every cup-shaped disc of the hundreds with which the restless tentacles are furnished ready at the slightest touch to grip whatever is near, not only by suction, but by the great claws set all round within its circle—and in the centre of this network of living traps ... the chasm-like mouth, with its enormous parrot-beak”—all this and more has been pictured by Mr. Bullen, from personal observation, in words which cannot be strengthened. No tale of monsters in bygone ages can well exceed it.

If further proof be needed of the part played by cuttlefishes in the larder of Sperm whales, it is given by those whales, which, when harpooned and in their dying agonies, throw up the contents of their vast stomachs. Out of the stomachs come great masses of undigested cuttlefish, cubic blocks many feet in diameter, swallowed whole and not yet broken up.

In 1895 an immense cuttlefish was thus disgorged by a whale, and was found on examination to belong to a new and unknown species. The head had vanished; but the body was clothed in a strong armour of neatly arranged scales. So this was veritably an “armoured” kind.

Another monster, ejected from the stomach of another whale, had great suckers, each sucker being supplied with “claws as powerful as those of a tiger.”[7] This last also had ocean-lamps, or “phosphorescent organs,” doubtless a help to himself in ocean depredations, and an added terror to myriads of fleeing fishes.

Yet neither strength nor speed, nor grasping arms, nor clinging suckers, nor tiger-like claws, nor parrot-like beak, can protect the cuttlefish against its supreme foe, the Sperm whale.

But it has a method of defence, or rather of escape, often efficacious even here. When in danger, it is able to pour forth a copious stream of black liquid, which so thickens and darkens the water around, that the wily creature is hidden, and slips away beyond reach of its pursuer.

The nervous system of the Cuttlefish is more developed than that of other Molluscs. Indeed, from the remarkable changes of colour seen when it is excited, and the tubercles which spring to view on its skin if it is made angry, one would be inclined to speak of its temperament as “highly irritable.” It also shows much more understanding than its cousins, the oysters and the clams.