96 THE WHITE RIVER BADLANDS 



terest to note also that while all living rhinoceroses have 

 feet that are functionally tridactyl, some of the ancestral 

 true rhinoceroses, at least so far as concerns the front feet, 

 were functionally tetradactyl. This is known to be true of 

 Trigonias osborni and is suspected of others. This lessening 

 of the number of functional toes corresponds to similar alter- 

 ations in other animals and indicates progressive change. 

 Indeed, the rhinoceroses show in many ways gradual trans- 

 formations, particularly with reference to the feet, the teeth, 

 and the development of horn cores. 



Among the Aceratheres Caenopus mitis was the small- 

 est, its height at the shoulders being approximately twenty- 

 eight inches. Among the Diceratheres Diceratherium schiffi 

 was the smallest. It was also most specialized. The largest 

 of the Aceratheres, in fact the largest of all the true rhin- 

 oceroses, seems to have been Caenopus platycephalus. It 

 considerably surpassed the present day Sumatran rhinoceros. 

 Among the others Caenopus copei was about the size of the 

 American tapir and Caenopus tridactylus, measuring seven 

 feet, nine inches in length, and four feet high to top of the 

 rump, was nearly as large as the Sumatran rhinoceros. 



LOPHIODONTIDAE 



The lophiodonts, closely related to the ancestral tapirs, 

 are the most generalized of all known perissodactyls. The 

 fossils that have been found are in general very fragmentary 

 but they indicate a group of animals of great interest. Much 

 uncertainty prevails as to the exact relationship of the 

 Lophiodonts, but they are known to have many of the primi- 

 tive characters of the tapir, the hyracodont, and the horse. 



CHALICOTHEEIDAE 



The study of fossil bones has oftentimes brought out 

 very unexpected information. The unravelling of the story 

 of the Chalicotheres is a good illustration of this in that it 

 presents a pronounced exception to Cuvier's law of correla- 

 tion. Certain peculiar foot bones found at Eppelsheim, 

 nearly one hundred years ago were pronounced by 

 Cuvier to be those of a gigantic pangolin (an edentate). 

 These were described by Lartet under the name Macrother- 

 ium (Big Beast). Later some skull fragments with teeth 

 found in the same Eppelsheim locality were described under 



