Fig. 173.—Skull of an Upper Eocene Perissodactyl (Dinoceras mirabilis), showing three pairs of horn-bases. Greatly reduced.—After Marsh.
In the Middle Eocene, the place of Coryphodon was taken by Dinoceras and allied forms. Some of the species nearly equalled the elephant in size, but had shorter and stouter limbs, each supported on five great toes—the most perfect possible sort of pedestal foot ([Figs. 172, 174]). They were heavily armed with immense canines on the upper jaws, and two or even three pairs of horns or hard protuberances on the head ([Fig. 173]). Creatures so supported and so armed, and living where food was plentiful, might well dispense with any great degree of intelligence, and their development of brain is consequently little better than that of Coryphodon. These great and characteristic Eocene families have no known successors; and in the Miocene age their place is taken by a very different group, that of which Brontotherium is the type ([Fig. 175]). They are creatures of huge size, with a pair of horn-cores on the nose, and feet with four toes in front and three behind, resembling in form those of the rhinoceros.
Fig. 174.—Fore-foot of Dinoceras. Greatly reduced.—After Marsh.
Fig. 175.—Skull of Brontotherium ingens (Marsh). Greatly reduced. A Miocene Perissodactyl.