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 Dicotylidae, contains but one genus, Dicotyles, with at most two species. The name of the animal is connected with the dorsal gland; the animal thus appeared to possess two navels. The Peccaries, exclusively confined to the New World, differ from the Old-World Pigs in one or more important characters. They have only three toes on the hind-feet, and the stomach is complicated. Though the Peccaries have but small tusks they hunt in packs and are very dangerous animals to meet with. They owe, too, their safety from many foes to their sociable habits. Being nocturnal animals they are liable to the attacks of the Jaguar, which will speedily overpower and devour a Peccary that has strayed from its herd.

Fossil Swine.—The existing genera of the Pig tribe are also known in a fossil condition. Sus itself goes back as far as the Upper Miocene. Sus erymanthius, the Erymanthine Boar, is known from beds of that age in Greece, England, and Germany. This genus is not known to have had a wider distribution in the past than it has in the present. Dicotyles occurs in the Pleistocene of both North and South America, the regions which it inhabits at the present day. The genus Listriodon, also Miocene, is remarkable for having lophodont instead of bunodont teeth, that is so far as concerns the molars, which resemble those of the Tapir. It was European and Indian in range. A number of genera, more remote from the existing Pigs than those which have just been dealt with, are placed together in a special sub-family, Achaenodontinae. The type genus, Achaenodon, had a somewhat short skull for a Pig; and it is in general aspect and in the characters of the canine teeth highly suggestive of that of a Carnivore. The bunodont molars, however, are Suine, as is the form of the lower jaw with a rounded angle. This is an Eocene animal found in Wyoming.

Elotherium occurs chiefly in the Miocene of both North America and Europe; but E. uintense is Eocene. The orbits are completely encircled by bone in the more modern forms; this is not the case in the last-described genus, with which E. uintense agrees. The skull is also longer and more Pig-like. The zygomatic arch is powerful, with sometimes a large descending process, such as is found in Diprotodon, more faintly in Kangaroos, and in Sloths and certain extinct Edentates. The lower jaw has a pair