270 LAND MAMMALS IN THE WESTERN HEMISPHERE 



lower jaw ; bony knobs on the end of the nose probably sup- 

 ported a pair of dermal horns like those of a rhinoceros and, 

 in addition, a pair of high, cyUndrical, horn-Uke, bony pro- 

 tuberances arose above the eyes and another, more massive 

 pair, near the back of the head. It would be difficult to imagine 

 more extraordinary creatures than the fuintatheres, which 

 were the largest land-mammals of their time. The family 

 was entirely confined to North America, no trace of them having 

 been found in any other continent. 



While the backward and archaic orders, most of which have 

 left no descendants in the modern world, had thus a stately 

 representation in Bridger times, they were outnumbered in 

 genera, species and individuals by the progressive orders, 

 which are still in more or less flourishing existence. The 

 Primates, whether lemurs or monkeys, were numerous, and 

 this, so far as is definitely known, was their last appearance 

 in extra-tropical North America. They may at any time be 

 found in the Uinta, but there is small probability that they 

 will ever turn up in the White River or later formations. 

 The many rodents all belonged to the fischyromyids, an extinct 

 family which, there is much reason to believe, was ancestral 

 to many families of the squirrel-like suborder of Sciuromorpha. 

 Most of them were species of a single genus {'\Paramys) and 

 varied in size from a mouse to a beaver, or even larger. 



The Perissodactyla may be said, in one sense, to have 

 reached their culmination in the Bridger; not that many of 

 them, such as the horses and rhinoceroses, did not advance 

 far beyond their state of development in the Eocene, but at no 

 subsequent time did the order as a whole possess such domi- 

 nating importance. There were five or six families of peris- 

 sodactyls in the Bridger, and their remains are much the most 

 abundant fossils found there. Individually, the commonest 

 perissodactyls of the time were the ftitanotheres, of which 

 there were several genera and many species, differing chiefly 

 in size and proportions, though the largest hardly exceeded 



