88 Annals of the Carnegie Museum. 



when the ungual phalanges of the present specimen are compared 

 with those of Protoreodon of the Uinta there is presented little or no 

 difference in detailed structure. When the equality in size of Prot- 

 agriochcerus and Agriochcerus is considered, there is revealed a remark- 

 able difference in the general proportions as well as the detailed struc- 

 ture of the limbs and especially of the feet^'' in the two genera. The 

 radical change from the general slenderness of the Uinta form to the 

 shorter and broader feet of the Oligocene genus, whatever caused this 

 comparatively rapid change, could not well be due to the increase in 

 size of the animal from the earlier to the later representative, as is 

 claimed in other cases from earlier to later phyla of the Tertiary. 

 While provisionally accepting Protoreodon as approximately in the 

 ancestral line leading to Merycoidodon and also acknowledging the 

 general mixture of similar characteristics between the Uinta protoreo- 

 donts, the Oligocene oreodonts, and Agriochcerus, so ably worked 

 out and presented by Professor Scott and referred to on a preceding 

 page of this paper, it is not clear that we should acccept Protagrio- 

 chcerus or any protoreodont of the Uinta Eocene, so far as at present 

 known, as being directly ancestral to Agriochcerus. The material of 

 this proposed genus of the upper Eocene is still entirely too fragmen- 

 tary. A critical survey of the taxonomy precludes our saying more 

 than that most of the known features of Protagriochcerus are indeed 

 very close to Protoreodon, if indeed, it is not congeneric with the latter. 



Family CAM ELI D.^. 

 Genus Protylopus Wortman. 

 24. Protylopus petersoni Wortman. 



Bull. Amer. Mus. Nat. Hist., Vol. X, 1S98, pp. 104-110. 



Among the specimens of this species the greater portion of a skeleton, 

 C. M. No. 2948, was found in the eastern part of the Uinta Basin at 

 the base of horizon C. The cervical region is imperfectly preserved, 

 but enough remains to make out some of the more important features, 

 which arc for the first time described below. A brief description of the 

 fore and hind foot is thought to be of value, especially since the tarsus 

 presents some curious features. The material represents an old indi- 

 vidual, of larger size than the type described by Dr. Wortman, and 



47 Agriochcerus gaudryi Osborn, the best preserved hind foot known, is used for 

 this comparison. 



