24 Departvient of Vertebrate PalcBontology. 



the Big Badlands of South Dakota. Its length is 9 ft. 7 inches. 

 The general impression is of a very broad, flat skull, with 

 formidable canine tusks; small, but prominent and greatly 

 elevated ej^e-sockets, and a very broad chest. The fore and 

 hind limbs are quite powerful, but the metapodials are rather 

 slender, especially in the manus. This animal is widely 

 separated from the true Rhinoceros by its four completely 

 functional digits on the fore foot and by the strong develop- 

 ment of the canines. 



OsBORN & WoRTMAN, Perissodactvls of the Lower Miocene, White 

 River Beds, Bull. Am. Mus. Nat. Hist., VII, 1895, pp. 373-375, 

 pU. X, xi. 



2. Brontotherium, sp. 



Am. Mus. No. siS. 



This skeleton represents the largest size and the last stage 

 in the evolution of the Titanotheres, and was discovered by 

 the American Museum Expedition of 1892 in the Upper 

 Titanotherium Beds of South Dakota, absolutely complete as 

 far back as the border of the pelvis. The hind limbs, belonging 

 to different animals, but of the proper proportions, were secured 

 in the same regions of the West in the summer of 1894, 



The complete skeleton, about 7 feet 7 inches (M. 2.31) 

 high; 13 feet 8 inches (M. 4.17) long, and 3 feet 10 inches 

 (M. 1. 1 7) broad, probably belongs to an adult female, as we 

 judge from the imperfect development and ossification of the 

 horns, which in males of this period are very long and power- 

 ful. An interesting feature of the skeleton is an exostosis and 

 false joint in the centre of the seventh rib, undoubtedly an 

 after-result of fracture. 



OsBORN & WoRTMAN, loc. cit., pp. 346-352, pll. viii, ix. 



3. Hyrachyus agrarius Leidy, 



Am. Mus. No. 5065. 



This is the original skeleton discovered by Professor Cope 

 himself in his explorations in the Bridger Basin (Middle 



