shape of the upper jaw depends upon the sockets, which receive the great tusks, and remind us of the Elephant. It will also be noticed, that the lower jaw shuts in between these tusks, and so rests upon the upper one. The great sockets are placed between the nostrils and the orbit, the rim of which is wanting for nearly one-third of its circumference. The cranium itself is not large; but its processes are well marked, serving for the insertion of the powerful muscles which move the head. The position of the grinders, and their shape, are here also seen, four on each side of each jaw, which, with the two tusks, makes eighteen in all; the grinders are small. Cuvier adds, that between the tusks are two incisors, shaped like molars, which the generality of writers have not yet recognised to be incisors; between these again are two small and pointed ones in young individuals.*

* In the preceding volume of the Naturalist's Library, (Mam. v. 7th,) our friend Mr MacGillivray having supplied, from the cranium of a young Walrus, in the Museum of the Royal College of Surgeons, the first published description of the normal dentition of this animal, we subjoin it. In the skull of the young, there are in the upper jaw three incisors on each side; the first or inner extremely small, the second a little larger, and the third or outer disproportionately large, being equal to the largest grinders. The canine tooth is displaced, being thrust outwards beyond the line of the other teeth; there are then five grinders, with single roots, the fifth very small. In the lower jaw there are two very small incisors on each side, the canine is wanting, and five grinders. In adults, the incisors are obliterated, except the lateral pair of the upper jaw; the fifth grinder also disappears, and sometimes the fourth.

THE WALRUS, OR SEA-HORSE.

Trichechus.-LINN.

PLATE I.

Trichechus, Linn. Trich. Rosmarus, Gmel. Equus Marinus, Ray. Morse of the Russians. Bête à la grande dent, of the French. Walros, Egede, Crantz, Anderson. Walrus, Pennant, Scoresby, &c. Sea-Horse of the Whale-fishers, and sometimes SeaCow.

IT has been well remarked, that the Walrus forms a connecting link between the Mammalia of the land and those of the water, corresponding in some of its characters both with the Bullock and the Whale. It is often seen of the size of a great Ox, and sometimes exceeds the dimensions of the gigantic Elephant. Its distinguishing characters are accurately and beautifully represented in the accompanying plate, taken from a specimen in the Edinburgh Royal Museum, as perfect a one perhaps as is to be found in Europe. The head, well proportioned to the body, is round and obtuse; the

eyes are small and brilliant; there are no external ears, and the orifice is placed far back on the head; the nostrils are large, somewhat round, and placed on the upper part of the snout. The most remarkable feature, however, in its countenance is its great muzzle, produced by the bony structure being accommodated for the reception of the tusks; these project from eighteen inches to two feet, and diverge at their points. The lips are remarkably thick, and are covered with great pellucid bristles as big as a straw. The neck is short; the body, very bulky, is broadest round the chest, and diminishes towards the tail, which is very short. As a defence against the extreme cold, these animals have a hide that is from an inch to two inches thick, covered with close hair; and they likewise possess, like the Whale tribe, a coating of oily fat, with which their bodies are completely enveloped. Thus incased, they descend to the depths of the Arctic Seas, and repose upon their icy beds without inconvenience. The colour, according to Fabricius, varies with the age; the young are black; they then become brown, and gradually more and more pale, till in old age they become quite white. Their limbs are short, and of an intermediate character between fins and legs; the inside of their paws are defended by a rough horny kind of coating, a quarter of an inch thick, which is probably produced by the hardening of the skin in consequence of the coarse usage they receive in climbing over the ice and rocks. The fore-paws, which are

a kind of webbed hand, are two-sevenths of the whole length of the animal from the snout; they are from two to three feet in length, and being expansive, they can be stretched to a considerable width. The hind-feet extend straight backwards, and together form a sort of tail fin; they are not, however, united, but are quite distinct from each other; their length approximates to that of the forepaws, and the termination of all the fingers and toes is marked by a small nail.

The common dimensions of the Sea-Horse are from twelve to fifteen feet in length, with a circumference of eight or ten. Crantz states that it reaches a magnitude of eighteen feet in length, and nearly as much in circumference; and Baron Cuvier states that it exceeds the bulk of the largest bulls, and attains a length of twenty feet.* The length of the tusks when cut out of the skull is commonly from fifteen to twenty inches, though they are sometimes almost thirty; and their weight is from five to ten pounds, though it is noted that they have sometimes been found the double of this on the shores of the Icy Sea. They are not only useful to the animal in procuring its food, but also as a weapon against its foes, of which the Bear on land, and the Sword-fish at sea, are amongst the most nimble and fierce; they are also employed in enabling the animal to raise its unwieldy bulk upon the ice, when its access to the shore is prevented.

• Règne Animal, edit. 1829.

Though we have been somewhat full in our description, yet we do not deem it superfluous to append a few sentences from the racy account of the Missionary Crantz." The head is oval, but the mouth so small that I could not quite put my fist into it. On both its lips, and on each side of the nose, is a kind of fungous skin, a hand's breadth, stuck with a plantation of monstrous bristles, that are a good span long, and as thick as a straw; they are like a three stranded cord, pellucid, and give to the animal a majestic though a grim aspect. The nose is very little raised, and the eye is not larger than an Ox's. I could perceive no eye-lid, and as I was at first searching for the eye and temples, a Greenland boy pressed the skin, and out sprang