Among the Perissodactyla, the rhinoceroses were perhaps the most conspicuous; the native American stocks of this family appear to have mostly died out and to have been replaced by two or more phyla of immigrants from the Old World, some of which were hornless, others had a small horn on the tip of the nose and others again had a second and smaller horn on the forehead. Tapirs, though unquestionably present, are rare as fossils and not well known. Several distinct phyla of horses may be distinguished, which were like small ponies in size, but of more slender form; they were all three-toed, but there were marked differences among them with regard to the degree to which the middle toe (the third of the original five) had been enlarged to carry the whole weight and the lateral toes (second and fourth) reduced to mere “dew-claws.” While browsing horses, with low-crowned teeth, still persisted in large numbers, we find also the extremely interesting beginnings of the highly complex, cement-covered and high-crowned teeth of the grazing kinds. The clawed †chalicotheres were present, though very little is known about them because of the fragmentary character of the remains. The Artiodactyla were much more varied and abundant, though they did not rival the great assemblage of these animals found in the European Miocene. Of the peccaries little more can be said than that they were present in these faunas. The †oreodonts were very numerous, both individually and generically; two stages of the proboscis-bearing kind are found here together, the older, long-faced genus (_†Promerycochœrus_) surviving from the Oligocene, while the newer Miocene type was short-faced and had a moderate proboscis (see Fig. 196, p. 373). Others had more the proportions of peccaries and still others were very small and presumably aquatic in habits. Camels abounded, both the grazing kinds which were ancestral to the modern forms of South America and Asia, and the great, browsing †giraffe-camels. The †hornless deer and the antlered †deer-antelopes were much like those of the Upper Miocene, slender and graceful little creatures, and there were also considerably larger ruminants (_†Dromomeryx_) with straight, simple and non-deciduous horns, which may be called antelopes. [Illustration: FIG. 127.—Gigantic †giraffe-camel (_†Alticamelus altus_) from the middle Miocene of Colorado. Restored from specimens in the American Museum of Natural History.]