13^ Bulletin American Museum of Natural History. [Vol. X, 



ground. In the lower molars of Auchenia there is a very promi- 

 nent buttress, amounting almost to a lamina, developed at the 

 outer extremity of the antero-external crescent, especially in the 

 second and third molars. This structure is not present in the lower 

 molars of any of the North American species which I have seen, 

 although there are faint traces of it to be found in some of them. 



As regards the generic name to be applied to these North 

 American species, I revive the one originally given by Leidy, 

 Camelops, notwithstanding the fact that no attempt was made by 

 him to give a generic definition. The extreme reduction of the 

 fourth premolar, together with the small size of the inferior 

 canine, satisfactorily distinguishes Eschatius, which is undoubtedly 

 a distinct genus and is here regarded as such. 



In the description of the numerous remaining species which 

 have been proposed, apparently very little latitude has been 

 allowed for individual and sexual variations, and because of the 

 very fragmentary condition of the material so far known any 

 accurate understanding of their limits is quite impossible. On 

 this account it is very difficult to determine what species are valid 

 and entitled to recognition. Until a larger number of specimens 

 in a less fragmentary state are obtained, I cannot distinguish more 

 than two, or at the utmost three species, and these determinations 

 rest solely upon size. 



Camelops kansanus Leidy. 



This species is by far the most abundant of all the North 

 American Pleistocene Cameloids, and of the widest geographical 

 distribution. I regard as synonymous of the above the following 

 specific names : Megalomeryx niobrarensis Leidy,' Auchenia hes- 

 terna Leidy, '^ Holomeniscus hesternus^ Cope, Auchenia huerfanensis 

 Craigin,* and Holomeniscus sulcatus Cope.^ Leidy 's type of 

 Camelops kansanus consists of a fragment of the anterior portion 

 only of the upper jaw, bearing the root of the incisor and a 

 portion of the alveolus of the canine, and does not reveal the 



> Proc. Acad. Nat. Sci. Phila., 1858, p. 24. 



^ Rep. U. S. Geolog. Surv. Territories, 1873, P- 225- 



^ Proc. Amer. Philos. Soc, 1S84, p. 16. 



^ Amer. Geologist, 1892, p. 257. 



' Rep. Geol. Surv. Texas, 1893, p. 84. 



