216 



GEOGRAPHICAL ZOOLOGY. 



[part iy. 



Oregon, and Arkansas. Elotherium is said to be allied to the 

 peccary and hippopotamus. Hi/opotamus, from the Miocene of 

 Dakota, is allied to Anthracotherium, and forms with it (accord- 

 ing to Dr. Leidy) a distinct family of ancestral swine. 



It thus appears, that the swine were almost equally well re- 

 presented in North America and Europe, during Miocene and 

 Pliocene times, but by entirely distinct forms ; and it is a re- 

 markable fact that these hardy omnivorous animals, should, like 

 the horses, have entirely died out in North America, except a 

 few peccaries which have preserved themselves in the sub-tropical 

 parts and in the southern continent, to which they are compara- 

 tively recent emigrants. We can hardly have a more convincing- 

 proof of the vast physical changes that have occurred in the 

 North American continent during the Pliocene and Post-pliocene 

 epochs, than the complete extinction of these, along with so 

 many other remarkable types of Mammalia. 



According to M. Gaudry, the ancestors of all the swine, with 

 the hippopotami and extinct Anthracotherium, Meryco;potamus, 

 and many allied forms, — are the Hyracotherium and FHolophus, 

 both found only in the London clay belonging to the Lower 

 Eocene formation. 



Family 48.— CAMELID^. (2 Genera, 6 Species).- 



The Camels are an exceedingly restricted group, the majority 

 of the species now existing only in a state of domestication. The 

 genus Camehis (2 species), is a highly characteristic desert form 



