Life and Adventure in the South Pacific

by John D. Jones

“The octopus, which was the animal denominated polypus by Aristotle, has eight arms of equal length, and contains in its interior two very small rudimentary shells, formed by the inner surface of the mantle. This shell becomes much more distinct in the loligo, where it is cartilaginous, and shaped like the blade of a sword. The internal shell of the common sepia is large and broad, and composed wholly of the carbonate of lime; it is well known by the name of cuttle-fish bone. Its structure is extremely curious, and deserves particular attention, as establishing the universality of the principle which regulates the formation of shells, whether external or internal, and from which structures differing much in their outward appearance may result. It is composed of an immense number of thin calcareous plates, arranged parallel to one another, and connected by thousands of minute hollow pillars of the same calcareous material, passing perpendicularly between the adjacent surfaces. This shell is not adherent to any internal part of the animal which has produced it, but is inclosed in a capsule, and appears like a foreign body impacted in the midst of organs with which, at first sight, it appears to have no relation. It no doubt is of use in giving mechanical support to the soft substance of the body, and especially to the surrounding muscular flesh; and this probably contributes to the high energy which the animal displays in all its movements. It has been regarded as an internal skeleton, but it certainly has no pretensions to such a designation; for, although enveloped by the mantle, it is still formed by that organ, and the material of which it is composed still carbonate of lime. On both these accounts it must be considered as a true shell, and classed among the productions of the integuments. It differs, indeed, from bony structures, which are composed of a different kind of material, and formed on principles of growth totally dissimilar. Besides tentacula, the sepia is also provided with a pair of fleshy fins, extending along the two sides of the body. The loligo has similar organs of a smaller size, and situated only at the extremity of the body which is opposite to the head. They have been regarded as the rudiments of true fins, which are organs developed in fishes, and which are supported by slender bones; but no structure of this kind exists in the fins of the Cephalopoda. In swimming, the organs principally employed by cuttle-fish for giving an effective impulse to the water are the tentacula. These they employ as oars, striking with them from behind forward, so that their effort is to propel the hinder part of the body, which is thus made to advance foremost, the head following in the rear. They also use these organs as feet for moving along the bottom of the sea. In their progress under these circumstances, the head is always turned downward and the body upward, so that the animal may be considered as literally walking on its head!

“The necessity of this position for the feet arises probably from the close investment of the mantle over the body; for, although the mantle leaves an aperture in the neck for the entrance of water to the respiratory organs, yet in other respects it forms a sack, closed in every part except where the head, neck, and accompanying tentacula protrude.

“In the calamary, as well as the common sepia, two of the arms are much longer than the rest, and terminate in a thick cylindrical portion, covered with numerous suckers, which may not inaptly be compared to a hand. These processes are employed by cuttle-fish as anchors, for the purpose of fixing themselves firmly to rocks during violent agitations of the sea; and accordingly we find that it is only the extremities of these bony tentacula that are provided with suckers, while the short ones have them also along their whole length. The other genera of cephalopodous mollusca are, like the sepia, provided with tentacula attached to the head. They comprehend animals differing exceedingly in size, some being very large, but a great number very minute, and even microscopic.”

Other animals of this kind inhabit shells, one of which is the nautilus, which, says Roget, “possesses a shell exceedingly thin and almost pellucid; probably for the sake of lightness, for it is intended to be used as a boat. For the purpose of enabling the animal to avail itself of the impulses of the air while it is thus floating on the water, Nature has furnished it with a thin membrane, which she has attached to two of the tentacula, so that it can be spread out like a sail to catch the light winds which waft the animal forward on its course. While its diminutive bark is thus scudding over the surface of the deep, the assiduous navigator does not neglect to apply its tentacula as oars on either side, to direct as well as to accelerate its motion. No sooner does the breeze freshen and the sea become ruffled than it hastens to take down its sail, and, quickly drawing its tentacula within its shell, renders itself specifically heavier than the water, and sinks immediately into more tranquil regions beneath the surface.”

Sir William Jardine, in speaking of the food of the sperm whale,[4] ventures to suggest to those who may have frequent opportunities of observing whether this whale may not also frequently resort to the medusæ, and minute fish which in so remarkable a manner supply food to some of the smaller, as well as the other genera of the gigantic whales. That there is an abundant supply of this sustenance, both in the Antarctic Ocean and the more smiling latitudes of the southern seas, can easily be proved by a reference to Lesson’s Statements, and also to the Journal of Captain Colnett, who, when near the southern point of America, observes: “During this forenoon we passed several fields of spawn, which caused the water to bear the appearance of barley covering the surface of a bank.”

Arbigny also remarks that “there are immense tracts off the coast of Brazil filled with small creatures so numerous as to impart a red color to the sea.” “Statements of this sort,” observes Sir William, “could easily be multiplied; and hence we can not but suppose that this kind of food, which is ascertained to afford such rich nourishment to the other great cetacea, may very possibly be appropriated by the sperm whale to the same purpose.”

This is an unaccountable error on the part of the compiler of the Naturalists’ Library. The apparent banks above mentioned, and which we have ourselves frequently seen in various parts of the ocean, are certainly formed by myriads of medusæ and other small animals, which form the sustenance of the Balæna mysticetus, or right whale’s food, which consists of animals of the shrimp kind, and other minute creatures, which are closely congregated and swarm in those animated “banks,” but of which the sperm whale never partakes; as it is not “very possible,” but quite impossible that he could do so, however inclined he might be, on account of the organization of his feeding apparatus, which may be readily seen when its form is referred to.

The Sepia octopus, or “sea squid,” sometimes reaches an enormous size. In the Philosophical Transactions for 1758 (777), after having given an interesting description of a specimen sent for examination, the editor states that “it can, by spreading its arms abroad like a net, so fetter and entangle the prey they inclose when they are drawn together as to render it incapable of exerting its strength; for, however feeble these branches or arms may be singly, their power united becomes surprising; and we are assured Nature is so kind to these animals that if, in a struggle, any of their arms are broken off, after some time they will grow again. It is evident,” he continues, “from what has been said, that the sea polypus or octopus must be terrible to the inhabitants of the waters in proportion to its size, for the close embraces of its arms and adhesion of its suckers must render the efforts of its prey ineffectual either for resistance or escape, unless it be endowed with an extraordinary degree of strength.”

A gigantic Cephalopoda was discovered by Drs. Bank and Solander, in Captain Cook’s first voyage, floating dead upon the sea, surrounded by birds, who were feeding on its remains. From the parts of this specimen which are still preserved in the Hunterian Collection, and which have always excited the attention of naturalists, it must have measured at least six feet from the end of the tail to the end of the tentacles.

But this last we must imagine a mere pigmy when we consider the enormous dimensions of the one spoken of by Doctor Swediaus,[5] whose tentacula or limbs measured twenty-seven feet in length. But let the doctor speak for himself: “One of the gentlemen,” says he, “who was so kind as to communicate to me his observations on this subject (ambergris), also, ten years ago, caught a sperm whale that had in its mouth a tentaculum of the Sepia octopodia nearly twenty-seven feet long! This did not appear its whole length, for one end was corroded by digestion, so that, in its natural state, it may have been a great deal longer. When we consider the enormous bulk of the tentacula here spoken of, we shall cease to wonder at the common saying of the fishermen, that the cuttle-fish is the largest fish of the ocean.”