HISTORY OF THE ARTIODACTYLA 409 



While there is little difference of opinion as to the propriety 

 of including in the family fHypertragiilidae the four phyla de- 

 scribed in the foregoing pages, the systematic position and the 

 relationships of that family as a whole are matters of debate 

 and hkely long to remain so. Dr. Matthew refers the entire 

 group to the suborder Tragulina and regards ^Leptomeryx as 

 being closely related to the direct ancestry of the American deer, 

 a view which is accepted by Professor Osborn, but in which I 

 am unable to concur. My own belief is that the family was an 

 early offshoot from the cameline stock and therefore referable 

 to the Tylopoda, in which suborder they are here included. It 

 would be out of place to enter upon a discussion of this per- 

 plexing problem, which can hardly receive a definitive solution 

 until the artiodactyls of the Uinta stage are thoroughly under- 

 stood. As in so many other series, the key of the mystery lies 

 hidden in the Uinta fauna, which is still so inadequately known. 



Suborder Pecora. True Ruminants 



This is the most advanced, specialized and diversified group 

 of the artiodactyls, though the ruminating habit is shared by 

 both Tylopoda and Tragulina. In this multitude of forms, 

 giraffes, deer, antelopes, sheep, goats, oxen, buffaloes, bisons, 

 etc., it is difficult to find a clue to a natural arrangement or 

 classification. As a whole, the suborder is a well-defined group, 

 and many structural characters, not all of which is it needful 

 to enumerate here, are common to all of its members. The 

 upper incisors are invariably absent, and, save in a few of the 

 deer, the upper canine also, while the lower canine has become 

 incisiform ; the premolars are always three in number in each 

 jaw and the molar-pattern is selenodont throughout. The 

 odontoid process of the axis is spout-shaped. Except in a few 

 deer, the Pecora all have bony outgrowths of the skull in the 

 form of antlers or horns, at least in the males, many females 

 being hornless. The ulna is co5ssified with the radius and the 



