Why does the cuttle-fish differ in structure from other mollusca?

Because it has three hearts - two of which are placed at the root of the two branchiae ; they receive the blood from the body, and propel it into the branchiae. The returning veins open into the middle heart, from which the aorta proceeds. - Cuvier.

The cuttle-fish was esteemed a delicacy by the ancients. Captain Cook also speaks highly of a soup he made from it; and the fish is eaten at the present day by the Italians, and by the Greeks, during Lent.

Why does the cuttle-fish, when pursued, eject a black inky liquor?

Because it may darken the water, and thus hide itself from its enemies.

It is a completely mistaken notion, that the black fluid of the cuttle-fish is its bile ; for the ink-bag is at a considerable distance from the gall-bladder. According to Cuvier, the Indian Ink, which comes from China, is made of the above fluid.

Why are the jaws of the cuttle-fish fixed in the flesh of the animal?

Because there is no head to which they can be articulated. They are of horny substance, and resemble exactly the bill of a parrot. They are in the centre of the lower part of the body, surrounded by the tentacula. By means of these parts, the shell-fish which are taken for food, are completely triturated.

Why have cuttle-fish small holes on their arms?

Because,by means of them, they fix themselves in the manner of cupping-glasses. These holes increase with the age of the animal; and, in some species, amount to upwards of 1,000. They have the power of reproducing their arms, which are often torn or nipped off by shell and other fishes.

The suckers of the cuttle-fish, are irregularly scattered on the arms and feet. The back is strengthened by a complicated calcareous plate, lodged in a peculiar cavity. This plate has long been known in the shop of the apothecary, under the name Cuttle-fish bone, which was formerly prized as an absorbent, but is now chiefly sought after for the purpose of polishing the softer metals. - Fleming.

Why is it improper to call this plate " bone "?

Because, in composition, it is exactly similar to shell, and consists of various membranes, hardened by carbonate of lime, without the smallest mixture of phosphate. - Hatchett, in Philos. Trans.

The most remarkable species of cuttle-fish inhabits the British seas; and, although seldom taken, its bone is cast ashore on different parts of the coasts, from the south of England, to the Zetland Isles. We have picked up scores of these bones, or shells, on the Sussex coast, but never found a single fish.

The cuttle-fish, it may be added, is the only animal of its class, in which any thing has hitherto been discovered, at all like an organ of hearing, or has been shown to possess true eyes.

Why are sea-grapes, as they are called, often picked up on the sea-shore?

Because many kinds are the ovaria, (or egg-bags) of cuttle-fish, and similar species.

Why are certain sea-worms called animal flowers?

Because they display beautiful membraneous expansions, resembling the petals of flowers: these are, in fact, the breathing organs, acting at the same time as tentacula.

Why does the stomach of some medusae resemble the roots of trees?

Because it has branching tentacula, on which canals commence by open orifices; these unite together to form larger tubes; and the successive union of these vessels, forms at last four trunks, which open into the stomach, and convey the food into that cavity. Cuvier has formed a new genus, under an appellation derived from the above comparison - the rhizostoma; from the Greek words, a root and a mouth.