PIN.NIGRADES, or PINNIPEDES. a section of carnivore, comprising seals and wal ruses, in which the fore and hind limbs are short and expanded into broad, webbed swimming paddles.. The hind feet are placed very far back, nearly in a line with the axis of the body, and somewhat incorporated with the tail by the integuments. The body is elongated and somewhat fish-like, covered with short fur or hairs, and terminated by a short conical tail. The five toes of each foot are united by the skin and form pow erful swimming paddles. The tips of the toes are armed with claws, but they have little power for land locomotion. the typical seals being able only to drag themselves along when out of the water. The ears are small, often only indicated by apertures, which the animal can close under water. The dentition varies, but teeth of three kinds are always present. The canines are always long' nd pointed, and the molars have sharp cutting edges. Sometimes there are only four or two lower incisors, and sometimes they are wanting altogether, as in the walrus, and the upper incisors may also be less than six. The dental formula of the common seal is 3 3 1 pm 4 4 1 = 34.
i 2 c 1 1 4 4 1 1 The pinnigrades include three families, the carless seals (phoeidcr), the eared seals (amides), and the walruses (trichee0a). The plweida3 differ from the walruses by hav ing incisor teeth in both jaws, and moderate-sized canines, and from the otaridm by the absence of ears and inability to use the hind limbs on land. They are very numerous,
being found in most seas of temperate and frigid zones, but are most numerous in title latter. Their principal food is fish, for hMding and masticating which their teeth are adapted. They are much hunted for their blubber and skins. The eared seals, or sat lions, differ from the typical seals by having small, conical ears, and in the greater tisie! of the limbs, especially the hind limbs, so that they are enabled to execute a sort of walk. The sea-lions are chiefly found in the Pacific and southern Atlantic, s. of La Plata river. The third family of pinnigrades, or bricheetilce comprises only the walrus or morse, and is distinguished from the true seals by the dentition. According to Owen there are six incisors in the upper jaw, and four in the lower, but these are only present in the young animal, soon disappearing, with the exception of the outer pair of upper incisors. The upper canines are enormously developed into long tusks, often over 15 inches. The upper jaw has on each side three premolars and two molars, with flattened crowns, and the lower jaw has the same number of premolars and one molar on each side; but the true molars are deciduous, so that the dental formula in the adult is 1 ; 3 0 0 1 1 1 3 3; m 0 0 = 18.
In all other respects the walruses are very similar to the seals. See MORSE, OTARY, and SEAL, ante.