The jaws of the Cuttle-fish, it should be observed, are fixed in the body because there is no head to which they can be articulated. They are of horny substance, and resemble the bill of a parrot. They are in the centre of the under part of the body, surrounded by the arms. By means of these parts, the shell-fish which are taken for food, are completely triturated.
We now come to the most peculiar parts of the structure of the Cuttle-fish, viz. the ear and eye, inasmuch as it is the only animal of its class, in which any thing has hitherto been discovered, at all like an organ of hearing, or that has been shown to possess true eyes.[10] The ears consist of two oval cavities, in the cartilaginous ring, to which the large arms of the animal are affixed. In each of these is a small bag, containing a bony substance, and receiving the termination of the nerves, like those of the vestibulum (or cavity in the bone of the ear) in fishes. The nature of the eyes cannot be disputed. "They resemble, on the whole, those of red-blooded animals, particularly fishes; they are at least incomparably more like them than the eyes of any known insects; yet they are distinguished by several extraordinary peculiarities. The front of the eye-ball is covered with a loose membrane instead of a cornea; the iris is composed of a firm substance; and a process projects from the upper margin of the pupil, which gives that membrane a semilunar form."[11] The exterior coat or ball is remarkably strong, so as to seem almost calcareous, and is, when taken out, of a brilliant pearl colour; it is worn in some parts of Italy, and in the Grecian islands by way of artificial pearl in necklaces.
Next we may notice the curious provision by which the Cuttle-fish is enabled to elude the pursuit of its enemies in the "vasty deep." This consists of a black, inky fluid, (erroneously supposed to be the bile,) which is contained in a bag beneath the body. The fluid itself is thick, but miscible with water to such a degree, that a very small quantity will colour a vast bulk of water.[12] Thus, the comparatively small Cuttle-fish may darken the element about the acute eye of the whale. What omniscience is displayed in this single provision, as well as in the faculty possessed by the Cuttle-fish of reproducing its mutilated arms! All Nature beams with such beneficence, and abounds with such instances of divine love for every creature, however humble: in observing these provisions, how often are we reminded of the benefits conferred by the same omniscience upon our own species. It is thus, by the investigation of natural history, that we are led to the contemplation of the sublimest subjects; thus that man with God himself holds converse.
"Bone," or plate.
The "bone" of the Cuttle-fish now claims attention. This is a complicated calcareous plate, lodged in a peculiar cavity of the back, which it materially strengthens. This plate has long been known in the shop of the apothecary under the name of Cuttle-fish bone: an observant reader may have noticed scores of these plates in glasses labelled Os Sepiae. Reduced to powder, they were formerly used as an absorbent, but they are now chiefly sought after for the purpose of polishing the softer metals. It is however improper to call this plate bone, since, in composition, "it is exactly similar to shell, and consists of various membranes, hardened by carbonate of lime, (the principal material of shell,) without the smallest mixture of phosphate of lime,[13] (or the chief material of bone.)
Eggs.
Lastly, are the ovaria, or egg-bags of the Cuttle-fish, which are popularly called sea-grapes. The female fish deposits her eggs in numerous clusters, on the stalks of fuci, on corals, about the projecting sides of rocks, or on any other convenient substances. These eggs, which are of the size of small filberts, are of a black colour.
The most remarkable species of Cuttle-fish inhabits the British seas; and, although seldom taken, its bone or plate is cast ashore on different parts of the coast from the south of England to the Zetland Isles. We have picked up scores of these plates and bunches of the egg-bags or grapes, after rough weather on the beach between Worthing and Rottingdean; but we never found a single fish.