. The age of mammals in Europe, Asia and North America. Mammals, Fossil; Paleontology. 180 THE AGE OF MAMMALS. Fig. 75. — Amyiiodonts, aquatic rhinoceroses of Europe and America. The Lower OUgo- cene Metamynodon of South Dakota. After original by Charles R. Knight in the American Museum of Natural History. The especially characteristic hoofed mammals, common to this great holarctic region and dominating in the two countries, which attain their maximum evolution and then disappear, are the following: Supposed Origin North America Types Diceratheres, pair-horned rhinoceroses. Amynodonts, amphibi
. The age of mammals in Europe, Asia and North America. Mammals, Fossil; Paleontology. 180 THE AGE OF MAMMALS. Fig. 75. — Amyiiodonts, aquatic rhinoceroses of Europe and America. The Lower OUgo- cene Metamynodon of South Dakota. After original by Charles R. Knight in the American Museum of Natural History. The especially characteristic hoofed mammals, common to this great holarctic region and dominating in the two countries, which attain their maximum evolution and then disappear, are the following: Supposed Origin North America Types Diceratheres, pair-horned rhinoceroses. Amynodonts, amphibious rhinoceroses with canine tusks " " Entelodonts, giant pigs with elongate skulls and stilted limbs Eurasia Anthracotheres, buno-selenodont artiodactyls, varied and attain- " ing giant size in Europe only. These animals are all descendants of Upper Eocene ancestors. Among artiodactyl ungulates we discover partly descendants of Eocene families, partly new invading forms, the latter especially seen in Europe. The pre- vailing artiodactyls common to both countries exhibit five-cusped, brachy- odont, buno-selenodont molar teeth (anthracotheres); bunodont teeth are more rare (suillines and entelodonts). True four-cusped selenodont molars of modern type are observed in the oreodonts and hypertragulids and, in more specialized form, in the smaller pro-ruminants, or gelocids, newl}^ arriving; also in the true ruminants, or cervulines, arriving in Europe in the Middle Oligocene, both probably of south Asiatic origin. It is noteworthy that all these primitive Oligocene ruminants of Europe, like their selenodont contemporaries, the hypertragulids in America, are hornless but usually provided with defensive Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Osborn, Henry Fairfield, 1857-1935. New
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectpaleontology, bookyea
