TRANSACTIONS OF WAGNER 



SO 



^ UINTA SELENODONTS 



The molars also are very like those of Protylopjis, though they are nar- 

 rower and somewhat more like those of Poebrother'mm in form. In size they 

 increase from m^, the smallest, to m^^, the largest of the series ; all of the 

 cusps are high and pointed, while the valleys are narrow and deep. The 

 inner cusps are already laterally compressed and are less conical than in the 

 other Uinta genera of selenodonts. The two external crescents are widely 

 separated, while the internal pair are more closely approximated, though with a 

 deep cleft between them ; a transverse valley is thus formed across the breadth 

 of the crown. Both internally and externally the gap between the fore and 

 hind crescents is spanned by a cingulum, which has a minute pillar arising 

 from it, best developed on the outer side. The third molar has a large basin- 

 like heel, but with a separate cusp on the inner side, which is low and ridge- 

 shaped, but very distinct. This cusp also recurs in Protylopus, but in none of 

 the other Uinta selenodonts which have been named. However, a third 

 genus with the same peculiarity is probably indicated by some specimens 

 in both the Princeton and New York collections, which are too imperfectly 

 preserved for definite generic reference. 



Of the milk dentition only dp^ is known, and this is- preserved in a speci- 

 men (No. 2509) belonging to the American Museum, in which the crown of 

 the permanent successor (p^) is already almost completely protruded. The 

 milk-tooth is of the usual selenodont pattern and is composed of three pairs 

 of crescents, but a primitive feature is to be seen in the comparatively small 

 size of the anterior pair. 



MEASUREMENTS. 



Lower P-2, length 

 " P-3, " 

 " P-4, " 

 •■ Dp-4, " 

 " M-i, ■• 

 " M-2, ■■ 



.006 



.0065 



.007 



The foot-bones which I referred to Lcptotragubis in a former paper 

 ('89, p. 482) were not found with the type specimen, which is a fragment of 

 the rnandible ; the reference was made on the strength of the tylopodan char- 



*Type specimen of genus, Princeton Museum, 

 •j- American Museum of Natural History. 



