Page:A History of Land Mammals in the Western Hemisphere.djvu/338

314 to a proper arrangement of the various species; in essentials, the forms all agreed and constituted several series of closely

allied genera. Comparing these Bridger animals with the great †titanotheres of the lower White River, the first and most obvious difference that strikes the observer is the very much smaller size of the more ancient types. With some variation in this respect, hardly any of the Bridger species exceeded a modern tapir in stature and very much resembled one in proportions. The canine teeth were tusks as large as those of a bear and must have been very effective weapons; the molar-pattern was identical with that found in the great Oligocene beasts, but the premolars were simpler and relatively smaller. The skull had a straight upper profile, though in several of the phyla small bony protuberances were developed over