The Nautilidæ are inhabitants of the Indian Ocean and the sea round the Molucca Islands. In swimming, their head and tentacles are projected from out of the shell. In walking on rocks they drag themselves along the ground, the body upwards, the head and tentacles beneath. They betake themselves frequently to miry cavities frequented by fish. It is a much more common occurrence to find the empty than inhabited shells of the Nautilus at sea. This, probably, arises from its exposure to the attacks of crustaceans and other marine carnivora. This seems to be proved by the mangled appearance of the edges in the empty shells thus met with.
Fig. 314. Shell of Nautilus pompilius (Linnæus).
The Pearly Nautilus, Nautilus pompilius (Fig. 314), is so common on the Nicobar coast that the inhabitants salt and dry its flesh, and store them as provisions. Its shell attains about eight inches in its greatest height. This shell is still used by the Hindoo priests as their conch or shell, with which they summon their devotees to worship. It is nearly round, smooth, transversely blazed in its posterior part, and entirely white anteriorly. A very fine nacre is yielded by this mollusc, which is much used in ornamental cabinet-work. The Orientals make drinking-cups, on which they engrave designs and figures, which form graceful objects. Similar vases were formerly shaped in Europe, which found their way into great houses. In our days they are generally consigned to cabinets of curiosities and the shops of dealers in articles of virtù.
Owen's second order, Dibranchiata, contains six families; the first is Spirulidæ, containing the curious Spirula, that little gem amongst oceanic shells. The second family is Sepiadæ, containing Belemnosis and Sepia. The third is Belemnitidæ; the fourth, Teuthidæ; the fifth, Octopodidæ; and the sixth, Argonautidæ.
Acetabuliferous Cephalopoda.
To this group belong the cuttle-fish, squids, and argonauts, among existing species, and the Belemnites among the fossil species. Some of these creatures are large, and essentially flesh-eaters, or carnivorous; and, if we may believe all that has been written respecting them, very formidable ones. Listen to Michelet, while he paints the warlike humour of these inhabitants of the deep:—"The Medusæ and Molluscs," says this popular author, "are generally innocent creatures, and I have lived with them in a world of gentle peace. Few flesh-eaters among them; those even which are so, only kill to satisfy their wants, living for the most part on life just commenced—on gelatinous animals, which can scarcely be called organic. From this world grief was absent. No cruelty and no passion. Their little souls, if mild, were not without their ray of aspiration towards the light, and towards what comes to us from heaven, and towards that love, revelling in that changing flame which at night is the light of the deep. It is now, however, necessary to describe a much graver world: a world of rapine and of murder; from the very beginning, from the first appearance of life, violent death appeared; sudden refinement, useful but cruel, purification, of all which has languished, or which may linger or languish, of the slow and feeble creation whose fecundity had encumbered the globe.
"In the more ancient formations of the old world we find two murderers—a nipper and a sucker. The first is revealed to us by the imprint of the trilobite, an order now lost, the most destructive of extinct beings. The second subsists in one gigantic fragment, a beak nearly two feet in length, which was that of a great sucker or cuttle-fish (Sepia). If we may judge from such a beak, this monster, if the other parts of the body are in proportion, must have been enormous; its ventose, invincible arms, of perhaps twenty or thirty feet, like those of some monstrous spider. The sucker of the world, soft and gelatinous! it is himself. In making war on the molluscs he remains mollusc also; that is to say, always an embryo. He presents the strange, almost ridiculous, if it was not also terrible, appearance of an embryo going to war; of a fœtus furious and cruel, soft and transparent, but tenacious, breathing with a murderous breath, for it is not for food alone that it makes war: it has the wish to destroy. Satiated, and even bursting, it still destroys. Without defensive armour, under its threatening murmurs there is no peace; its safety is to attack. It regards all creatures as a possible enemy. It throws about its long arms, or rather thongs, armed with suckers, at random." Such is the somewhat exaggerated picture which the eloquent historian and poet draws of the Molluscous Cephalopod, and it must be admitted that there is a basis of truth in this, as well as in the more recent one painted by Victor Hugo, in his eloquent book, "Les Travailleurs de la Mer." Where, however, there is so much of the fictitious floating about, it will be our endeavour to eliminate facts only.
Family of the Sepiadæ.
The body of the cuttle-fish (Sepia) is thus a very singular structure, somewhat reminding us of certain species of polyps. We find a body or abdominal mass, hand ahead, separated by compression, sufficiently marked. The body is covered by the mantle, which has the form of a sac opened only in front by a transverse cleft. The head has a projecting and well-developed eye on each side; it is surmounted by a sort of fleshy funnel, which is divided by four pairs of tentacles. At the bottom of this tentacular funnel is the mouth; and from the anterior opening in the mantle a tube issues, which is wide at its base.