CHAPTER I.. The Octopus and Its Relatives.

THE OCTOPUS AND ITS RELATIVES.

It is not my intention to formally portray the anatomy of the Octopus,—the nature and uses of its various organs will be sufficiently indicated in the course of my remarks,—but before giving an account of its life-history and habits, I will briefly describe its affinities, and the position it occupies in the scale of Nature.

One of the great primary groups or divisions of the Animal Kingdom is that of the soft-bodied MOLLUSCA; which includes the cuttle, the oyster, the snail, &c. It has been separated into five “classes,” of which the one we have especially to notice is the Cephalopoda, or “head-footed,”—the animals belonging to it having their feet, or the organs which correspond with the foot of other molluscs, so attached to the head as to form a circle or coronet round the mouth. Some of these have the foot divided into eight lobes, and are therefore called the Octopoda: others have, in addition to the eight feet, lobes, or arms, two longer tentacular appendages, making ten in all, and are consequently called the Decapoda.

Of the ten-footed section of the cephalopods, there are four “families”; two only of which exist in Britain—the Teuthidæ, and the Sepiidæ. The Teuthidæ are the Squids, or Calamaries, represented by the long-bodied Loligo vulgaris, that has along its back a gristly, translucent stiffener, shaped like a quill pen; from which and its ink it derives its names of “calamary,” “pen-and-ink fish,” and “sea-clerk.” The Sepiidæ are the Cuttles; as a type of which we may take the common “cuttle-fish,” Sepia officinalis, the owner of the hard, calcareous shell often thrown up on the shore, and known as “cuttle-bone,” or “sea-biscuit.”

Of the eight-footed cephalopods,—the Octopoda,—there are two families; namely, the Octopidæ, and the Argonautidæ. The first only is found on our coasts. The British members of it are the common Octopus, O. vulgaris, and the Eledone, E. cirrosa, a genus chiefly distinguished from the octopus by its having only one row of suckers, instead of two, along its arms or feet. The Argonautidæ, which inhabit warmer seas than ours, and approach no nearer to us than the Mediterranean and Adriatic, are represented by Argonauta argo, the “Paper Nautilus,”—so called from the peculiar texture of its shell, and the similarity of its shape to that of the true Nautilus, N. pompilius, from which, however, it differs greatly in organisation.

All of these four “families” have two plume-like gills,—one on each side—and are therefore placed by Professor Owen in the “order,” Dibranchiata. To this order belong also the extinct Belemnites, and the still living Spirula, only one entire specimen of which has ever been obtained, and that was in New Zealand, though its beautiful internal shells are sometimes thrown up on the shores of Devon and Cornwall.

The Tetrabranchiata, or four-gilled cephalopods, are represented by a single living genus—the Pearly Nautilus, N. pompilius,—but in Silurian times by 34 genera, and more than 1400 species.

The following diagram will help to explain the relationship of the Octopus to the rest of the cephalopoda.

MOLLUSCA. /----------------------—|---------------------------\ Classes. Cephalopoda. Pteropoda. Lamellibranchiata. | Gasteropoda. Brachiopoda. | /----|---------------------------------------\ Orders. Dibranchiata. Tetrabranchiata. | | /----|-------------—\ /-------------|------------\ Sections. Decapoda. Octopoda. Nautilidæ. Ammonitidæ. | | Orthoceratidæ. | +------------------------+ | | /----|-----------------------\ /--------—|---------—\ Families. Teuthidæ. Sepiidæ. Spirulidæ. Octopidæ. Argonautidæ. | Belemnitidæ. | | | | | | | /--|---—\ /-----—|--—\ /----|-----\ | Genera. The Squids: The Cuttles: The Octopus; | Loligo, &c. Sepia, &c. O. vulgaris, &c. | | /-----------|-----\ The Paper Nautilus: Argonauta.

It will be seen that it may be said to be first cousin to the Argonaut, or “Paper Nautilus,” and second cousin to the cuttle and squid.

The Argonaut branch of the family is in possession of all the house property, which seems to have been entailed on the female line; for the paper-nautilus is, in fact, a female octopod provided with a shell in which to carry and protect her eggs. Instead of the whole of the eight arms tapering to a point, as in the octopus, two of the dorsal limbs are flattened out at their extremity, and from their membranes she secretes, and, if necessary, repairs the shell, and, by applying them closely to its outer surface on each side, holds herself within it; for it is not fastened to her body by any attaching muscles.

The male argonaut is very small,—not more than an inch in length,—and has no shell. Hence, even by eminent naturalists, as Dumeril and De Blainville, it was long regarded as doubtful whether the shell was really secreted by the female, or whether, like the hermit-crab, she borrowed for her protection the empty habitation of some other mollusc.

It is an old belief, sanctioned by Aristotle, that the broad membranous expansions of the two arms, are hoisted by the animal as sails; and that in calm weather it sits in its boat-like shell, and floats over the smooth surface of the sea, steering and paddling with its other arms; and that, when danger threatens, it lowers its masts, and sinks beneath the waves.

Oppian, in his “Halieutics,” poetically expresses his opinion that it served as a model for the man who first conceived the idea of constructing a ship, and embarking on the waters:—

“If humble guess may probably divine, And trace th’ improvement to the first design, Some wight of prying search, who wond’ring stood When softer gales had smoothed the dimpled flood, Observed these careless swimmers floating move, And how each blast the easy sailor drove; Hence took the hint, hence formed th’ imperfect draught, And ship-like fish the future seaman taught. Then mortals tried the shelving hull to slope, To raise the mast, and twist the stronger rope, To fix the yards, let fly the crowded sails, Sweep through the curling waves, and court auspicious gales.”

This pretty fable was exploded in 1837 by Captain Sander Rang, an officer of the French navy, and Port-captain at Algiers, who carefully followed up some experiments communicated to him by Mrs. Power, a French lady then residing at Messina; and the structure and purpose of the two flattened limbs is now clearly understood.

Instead of floating in its pleasure-boat over the sea, the argonaut ordinarily crawls along the bottom, carrying its shell above it, keel uppermost; and the broad extremities of the two arms are not hoisted as sails, nor allowed, when at rest, to dangle over the side of the “boat,” but are used as a kind of hood by which the animal retains the shell in its proper position, as a man bearing a load on his shoulders holds it with his hands. When it comes to the surface, or progresses by swimming instead of walking, it does so in the same manner as the octopus; namely, by the forcible expulsion of water from its funnel-like tube.

This “paper-sailor,” then, whom the poets have regarded as endowed with so much grace and beauty, and living in luxurious ease, is but a fine lady octopus after all. Turn her out of her handsome residence, and, instead of the fairy skimmer of the seas, you have before you what Mr. Mantalini would call a “dem’d damp, moist, unpleasant body,” like that of her weird and sprawling relative. The Paper Nautilus has been regarded as the analogue of the snail, which, like it, secretes an external shell for the protection of its soft body; and the octopus as that of the garden slug, which, having organs like those of the snail, as the octopus has organs like those of the shell-bearing argonaut, has no shell. The Cuttles and Squids may be compared to some of the sea-slugs, as Aplysia and Bullæa, and to some land-slugs, as Parmacella and Limax, which have an internal shell.

The female octopus not being furnished with a shell, none of her arms are modified in form, like those of the argonaut, for the purpose of secreting and holding one. The male octopus, also unlike the male argonaut, is as large as the female, but may easily be distinguished from her by his having numerous tubercles and papillæ on the skin, which become very prominent when he is irritated or excited. D’Orbigny, not recognizing this peculiarity as sexual, regarded it as a specific distinction, and made of the male octopus a separate species, O. tuberculatus.

Having briefly explained the generic history and relationship of the octopus, I propose to introduce to the reader some members of the family with whom I have been on friendly terms. A former casual acquaintance with some of their kinsfolk at the sea-side, ripened, afterwards, into a close and prolonged intimacy with them in their home; and I thus obtained an insight of their habits and peculiarities, many of which are very curious and interesting.