The motions of the seal on land are constrained and peculiar. The fore feet are but little used, and the body is thrown forward in a succession of jerks produced by a contraction of the spine. Awkward as this mode of progression seems, it is, nevertheless, exceedingly rapid. The seal, however, never ventures far from the shore, and the moment it is disturbed or alarmed it plunges into the water. The physiognomy of the animal is in perfect accord with its character, and expresses a considerable degree of intelligence combined with much mildness of disposition. The eyes are large, black, and brilliant; the nose is broad, with oblong nostrils; and there are large whiskers. The seal has no external ears, but in the auricular orifices exists a valve which can be closed at will, and protects the internal organism from the water; the nostrils possess a similar valve. The body is thickly garnished with stiff glossy hairs, very closely set against the skin, and plentifully lubricated with an oily secretion, so that the surface is always smooth, and unaffected by water. The teeth differ in different genera, but in all are specially adapted for the seizure of fish and other slippery prey, though the seals are omnivorous in their habits, and will partake both of vegetable and animal food. There are either six or four incisors in the upper, and four or two in the lower jaw; the canines are invariably large and strong; and the molars, usually five or six on either side, in each jaw, are sharp-edged or conical, and bristle with points. The seal is fond of swallowing large stones; for what purpose is not certain, but, probably, to assist digestion. Seals live in herds, more or less numerous, along the frozen shores of the Arctic seas; and on the lonely deserted coasts they bring forth their young, over which they watch with singular affection. They swim with much rapidity, and can remain a considerable time under water. They are migratory in their habits, and at least four species visit our British waters. On the northern coasts of Greenland they are observed to take their departure in July and to return again in September. They produce two or three young at a time, and suckle them for six or seven weeks in remote caverns and sequestered recesses; after which they take to the sea. The young exhibit a remarkable degree of tractability; will recognize and obey the maternal summons; and assist each other in distress or danger. Many, if not all, of the species are polygamous, and the males frequently contend with desperate courage for the possession of a favourite female.