114 R. S. Lull — Primitive Pecora in Yale Museum. 



he says "I can not distinguish the John Day species from 

 the H. calcaratus, although the size is generally distinctly 

 larger." He does, however, use the John Day material 

 for his description of the morphology of the feet of the 

 genus, but this part of his description is generic and not 

 specific. 



The type skull is fairly complete, except that it is 

 injured in the pterygoid region, and represents a fully 

 mature animal in which the tooth pattern of M 1 is entirely 

 obliterated. Anteriorly, a portion of the large canine 

 alveolus is present, but no trace of the premaxillaries is 

 preserved. There is no jugal process, but the postorbital 

 process of the frontal forms about half the posterior 

 margin of the orbit. Scott's figure, which was drawn by 

 Mr. R. Weber, is the more accurate of the two except for 

 the restoration of the superior canine behind the canini- 

 form P 1? which the author evidently mistook for the true 

 lower canine tooth. Scott further restores the orbit as 

 though it were closed behind, for which there is no 

 evidence. 



Allomeryx planiceps Sinclair. 



This form agrees with Hypertragulus in the absence of 

 the mesostyle on the molars and in the development of 

 the metastyle on M 3 . It is distinguished by the closure 

 of the orbit behind by the frontal and jugal processes 

 which overlap but are not completely fused. The bullae 

 are small and separated from the basi-occipital by an 

 outgrowth of the petrosal. The brain-case is shorter 

 than in Hypertragulus, and the interorbital tract and 

 sagittal crest lie in one plane. 



Merriam and Sinclair in a later paper (1907) doubt the 

 generic rank of these several characters. The closure of 

 the orbit, however, is an evolutionary advance which is 

 significant, especially as in the known species of Hyper- 

 tragulus the jugal process is undeveloped. 



An imperfect skull, No. 10227, Y. P. M., shows Allo- 

 meryx characters in so far as preserved, especially those 

 noted in the basicranial region. It also possesses an 

 ample brain-case. Unfortunately the postorbital region 

 is not preserved. The Yale skull is from the upper John 

 Day beds. 



