SUCCESSIVE MAMMALIAN FAUNAS 



259 



derived. The unquestionably Old World family, that of the 

 fanthracotheres, was represented in the White River by two 

 genera {'\Bothriodon and'\Anthracotherium), which were short- 

 legged, long-snouted, swine-like animals, which have no near 

 relations in the modern world. The other family, the f giant 



Fig. 136. — ^Meri/coidodon culbertsoni, the most abundant of White River toreodonts. 

 Restored from a skeleton in the American Museum of Natural History. 



pigs, which we have already met with in the lower Miocene 

 and upper Oligocene, is of doubtful origin, and nothing has yet 

 been found in the preceding formations of either North America 

 or Europe which can be regarded as ancestral to them. The 

 White River genus {^ArchcBotherium) was very like the John 

 Day and Arikaree genera, but most of the species were much 

 smaller and some were not so large as a domestic pig. In the 

 uppermost beds, however, are found huge species, which 

 rivalled those of the subsequent formations. That these 

 strange animals were rooters and diggers and therefore pig-like 

 in habits is indicated by the manner in which the teeth are worn. 



