THE CENOZOJC AGE. 217 



scribed by Leidy, he has named Paleosyops paludosus. It had 

 forty-four teeth, and formed nearly an unbroken arch. The canines 

 were proportionately as large, and of the same form as in the bears. 

 It was about the size of the existing tapir of South America. In 

 tjie structure of the mouth and teeth it resembled the Paleotherium 

 of the European Eocene. From the structure of its mouth, Leidy 

 concludes that, like the bears, it was omniverous. Another species 

 (P. majo?'}, was as large as the Indian Rhinoceros.. Several other 

 species have been described. A still more curious species, described 

 by Leidy, was the gnawing hog (Trogosus). The two species ot 

 this genus combined the characters of the tapirs with those of the. 

 gnawing animals. The incisor teeth did not .extend so far back as 

 in the rodents, and in this respect approached the hog and pecary. 

 Unlike the rodents, however, the worn slope of the incisors is 

 directed both backwards and forwards. No canines existed ap- 

 proaching in this respect the Hyrax, Mastodon, Elephant and 

 Rhinoceros. 



Another tapir-like genus of animals was the Hyrachyus, of which. 

 six species have been described by Leidy, Marsli and Cope. They 

 differed from the South American tapir only generically, and aver- 

 aged about the same in size. From the great numbers of their re- 

 mains, they must have been exceedingly abundant during this 

 period. Thus one of the animal forms most common in North 

 America in Eocene times still persists in the tropical regions of this 

 continent. Many other genera of tapiroid species have been de- 

 . scribed from this basin to which I cannot even allude. 



The Mountain Horse (Orohippus], similar to the Eohippus of the 

 Vermillion beds, but wanting the fifth toe, is also found in this group. 



Perhaps the most remarkable mammals yet discovered in rocks 

 of any geological age, are the Dinocerata, which received that name 

 from Marsh, who regards them as the type of a distinct and new 

 order. He gave them this name because of the peculiarities of 

 their heads, which were armed, some of them with three and some 

 of them with two pairs of horns. They were " terribly horned." 

 Cope, on the other hand, does not attach the same weight to these 

 characters, and merely considers them to be a sub-family of the ele- 

 phants {Proboscidians}. He claims that they had trunks similar to 

 the elephants. Marsh denies this, on the ground that the naral 

 opening and general structure of the head unfitted it for carrying a 

 large trunk or proboscis, and because their short limbs and longer 



