TRANSACTIONS OF WAGNER 

 66 



UINTA SELENODONTS 



specialized in a way peculiar to itself, and with a tendency to simulate the 

 Pecora in some respect or other, yet always retaining a number of primitive 

 features. I cannot but believe that Protoceras represents a divergent offshoot 

 of the same stock, which, retaining in most respects the foot structure belong- 

 ing to the common ancestor of all these genera, has, at the same time, won- 

 derfully paralleled the higher Pecora in many features of the skull." ('95^, 



P- 365-) 



The newly discovered material of Leptomeryx and Hypertragulus brings 

 out very clearly their tylopodan affinities and confirms Rutimeyer's views 

 concerning them. If Lcptorcodon be the ancestor of Protoceras, as there is so 

 much reason to believe, there is all the more reason to refer the latter to 

 the Tylopoda, for it would be difficult to assign any ground for making more 

 than a family distinction between the former and Protylopus, almost the only 

 important difference between them being in the character of the canine teeth. 



In my preliminary paper I suggested that Lcptorcodon was the forerunner 

 of Leptomeryx also ('98, p. 77), but since I have seen the specimens belong- 

 ing to the American Museum, especially the fine skull which has been 

 figured by Wortman, this view strikes me as less probable. The skull seems 

 a little too large and heavy, and the orbit to have been shifted too far back, to 

 belong to a forerunner of Leptomeryx. Nevertheless, the ancestor of the latter 

 must have been some closely similar form, possibly even a smaller species of 

 the same genus. However that may be, the significant fact remains that in 

 the Uinta all these lines, including the main tylopodan series, are seen con- 

 verging very nearly to a common term. 



The relation of Lcptorcodon to the oreodonts offers a somewhat difficult 

 problem. Its most striking resemblance to this family is to be found in the 

 canine teeth and the caniniform first lower premolar, but the example of Lepto- 

 meryx and Protoceras shows that this peculiar arrangement is not confined to 

 the oreodont family. Certain other resemblances to the latter family also 

 occur in the limbs, as in the shape of the humeral trochlea and head of the 

 radius, but the feet are of quite a different type and approximate rather to 

 those of Protylopus. I am, however, inclined to the opinion that the resem- 

 blances to the oreodonts are not accidental, but that they have a real signifi- 

 cance and tend to connect that family with the Tylopoda. The late Professor 

 Cope once said to me that he believed Protoceras to be allied to the oreo- 

 donts, though I am not aware that he published this view. It is of impor- 

 tance as indicating the resemblances, which, though masked, could not escape 



