42 Department of Vertebrate Palceontology. 



8. Uintatherium, Six-horned Middle Eocene Amblypod. 



The male and female here represented are based upon 

 skeletal material as yet unmounted in the American Mu- 

 seum Collection, also upon the reconstruction published by 

 Professor O. C. Marsh. The structure of the male skull, as 

 here represented, corresponds with the largest type ever 

 found, that of the Uintatherium cornutum skull, discovered by 

 Professor Cope himself, and now in the American Museum. 

 There is no indication of a proboscis, nor is there any reason 

 to believe that the bony protuberances bore horns, many of 

 them expanding at the tip, as is never the case with true 

 horn-cores. The tusks, both in male and female, are found 

 chiefly worn upon the posterior surface, a fact which suggests 

 that they were used upon branches in drawing leaves and 

 shrubs into the mouth, as represented in the female figure in 

 the rear. Their chief function was probably as weapons of 

 defence or attack, the exceptionally wide gape of the jaw, as 

 indicated by the position and form of its muscular attach- 

 ments, giving room for their use in a very effective manner. 



Originally reproduced by Osborn in the Century Magazine, September, 1S96. 



Cope, Tertiary Vertebrata, pp. 569-587, pU. xxxvii-xlii. 

 Marsh, The Dinocerata, U. S. Geol. Sur. Mon.,X,pp. 1-243, pU. i-lvi, 

 1886. 



9. Hyracodon, Cursorial Oligocene Rhinoceros. 



This restoration is based also upon material in the American 

 Museum and Princeton Collections. The general conception of 

 Hyracodon as a running type was outlined by Scott in 1883. 

 These animals thus presented the widest contrast to the 

 swimming Rhinoceroses, or Metamynodon, on the one side, 

 and the low-land or swamp Rhinoceroses, the Aceratheres , on 

 the other. The upper molar teeth, however, closely resemble 

 those of the Rhinoceros, and form the motive for the re- 

 semblance to this animal, which is given in the face. The 

 trunk and limbs, on the other hand, resemble very closely 



