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, [5]  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 segments, and are therefore called the Octopoda: [6]  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 Calamaries, popularly known as "Squids," and are represented by the long-bodied Loligo vulgaris, that has internally along its back a gristly, translucent stiffener, shaped like a quill-pen; from which and its ink it derives its names of "calamary" (from "calamus," a "pen"), "pen-and-ink fish," and "sea-clerk." The Sepiidæ are generally known as the Cuttles proper. As a type of them 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."

It must here be remarked, that as these head-footed mollusks are not "fish," any more than lobsters, crabs, oysters, mussels, &c., which fishmongers call "shell-fish," are "fish," the word "fish" is misleading, and should be abandoned; and secondly, that the names "cuttle" and "squid," as distinctive appellations, are unsatisfactory. The word "cuttle" is derived from "cuddle," to hug, or embrace—in allusion to the manner in which the animal seizes its prey, and enfolds it in its arms; and "squid" is derived from "squirt," in reference to its habit of squirting water or ink. But as all the known members of the class, except the pearly nautilus, Nautilus pompilius, have these habits in common, the distinguishing terms are hardly apposite. As, however, they are conventionally accepted and understood, I prefer to use them. As with other mollusks, so with the cephalopods, some have shells, and some are naked or have only rudimentary shells. The Argonaut, or 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 argonaut and the other families of the cephalopods do not come within the scope of this treatise; we will therefore confine our attention to the three above mentioned. Of the anatomy and homology of the Octopus, Sepia, and Calamary we need say no more than will suffice to show in what manner they resemble each other, and wherein they differ, in order that we may the more clearly perceive to which of them the story of the Kraken probably owes its origin.

The octopus, the sepia, and the calamary are all constructed on one fundamental plan. A bag of fleshy muscular skin, called the mantle-sac, contains the organs of the body, heart, stomach, liver, intestines, a pair of gills by which oxygen is absorbed from the water for the purification of the blood, and an excurrent tube by which the water thus deprived of its life-sustaining gas is expelled. The outrush of water with more or less force, from this "syphon-tube," is also the principal source of locomotion when the animal is swimming, as it propels it backward—not by the striking of the expelled fluid against the surrounding water, as is generally supposed; but by the unbalanced pressure of the fluid acting inside the body in the direction in which the creature goes. Into this syphon-tube, or funnel, opens, by a special duct, the ink-bag; and from it is squirted at will the intensely black fluid therein secreted. I doubt very much the correctness of the statement mentioned by Pontoppidan and others, that the cuttle ejects its ink with a desire to lie hidden and in ambush for its intended prey, or with the intention to attract fish within its reach by their partiality for the musky odour of this secretion. It may be so, but during the long period that I had these animals under close observation at the Brighton Aquarium, I never witnessed such an incident. I believe that the emission of the ink is a symptom of fear, and is only employed as a means of concealment from a suspected enemy. I have found, that when first taken, the Sepia, of all its kind, is the most sensitively timid. Its keen, unwinking eye watches for and perceives the slightest movement of its captor; and if even most cautiously looked at from above, its ink is belched forth in eddying volumes, rolling over and over like the smoke which follows the discharge of a great gun from a ship's port, and mixes with marvellous rapidity with the surrounding water. But, like all of its class, the Sepia is very intelligent. It soon learns to discriminate between friend and foe, and ultimately becomes very tame, and ceases to shoot its ink, unless it be teased and excited. By means of the communication between the ink-bag and the locomotor tube, it happens that when the ink is ejected, a stream of water is forcibly emitted with it, and thus the very effort for escape serves the double purpose of propelling the creature away from danger, and discolouring the water in which it moves. Oppian has well described this—

Professor Owen has remarked that the ejection of the ink of the cephalopods serves by its colour as a means of defence, as corresponding secretions in some of the mammalia by their odour.

It is worthy of notice that the pearly nautilus and the allied fossil forms are without this means of concealment, which their strong external shells render unnecessary for their protection.

From the sac-like body containing the various organs, protrudes a head, globose in shape, and containing a brain, and furnished with a pair of strong, horny mandibles, which bite vertically, like the beak of a parrot. By these the flesh of prey is torn and partly masticated, and within them lies the tongue, covered with recurved and retractile teeth, like that of its distant relatives, the whelk, limpet, &c., by which the food is conducted to the gullet. Around this head is, as I have said, the organ which is equivalent to the foot in other molluscs—that by which