9 2 



TRANSACTIONS OF WAGNER 



UINTA SELENODONTS 



is somewhat lower vertically ; its palatine processes are narrow and short, 

 and quite concave transversely. The palatal notches are very shallow, and, 

 as the jugal joins the maxillary farther back than in Orcodon, the alveolus of 

 m^ is not so bar-like as in that genus. The palatines are quite large and make 

 up an extensive part of the bony palate, reaching forward to pA. As in Oreodon, 

 the palate is of nearly uniform width throughout. The posterior nares are inter- 

 mediate in character between those of Oreodon and those of Agriochccvus ; they 

 are wider than in the latter, but extend farther forward than in the former (to 

 m- 2 -), and thus the fore-and-aft extent of the canal is considerably greater. 



The mandible is as characteristically oreodont as the rest of the skull; the 

 horizontal ramus is of moderate length, but deep and compressed, tapering 

 forward to the abruptly inclined chin. The symphysis is short and very steep, 

 and in old individuals the two rami are sometimes coossified at this point. 

 The shape of the symphyseal region is one of the most marked differences 

 between Protoreodon and the other Uinta selenodonts, such as Protylopus and 

 Lcptoreodon. The ascending ramus of the mandible is shaped very much as 

 in Orcodon but is lower, the condyle being raised much less above the level of 

 the teeth. The angle is very broad and extends well behind the condyle, 

 decidedly more than in Orcodon, but less than in Lcptoreodon ; its border is 

 thickened, as in the former. The coronoid process is higher and more re- 

 curved than in the White River genus, and the masseteric fossa extends 

 farther down upon the jaw. 



MEASUREMENTS. 



Skull, basal length .... 



Cranium, length to anterior margin of orbit 



Face, length, orbit to premaxilla 



Sagittal crest, length 



Zygomatic arch, length 



Skull, breadth across zygomata 



Mandible, length . 



" depth at m-j 



" Pt 

 " breadth of angle . 



" height of condyle 



The brain is relatively smaller than in Orcodon and much more simply 

 convoluted. The hemispheres are particularly small, leaving the cerebellum 



. parvus. 



P. paradox 



o. 127 



0.132 



■073 



.081 



.061 



.051 



.052 



.060 



.059 



.056 



.086 



.078 



? . I 1 2 



? . 109 



.02I 



.026 



.Ol8 







.045 





.047 



