540 



PROCEEDINGS OF TEE NATIONAL MUSEUM. 



vol. 48. 



a quite simple pattern, approaching in this respect some of the species 

 of Protohippus. 



In all the upper premolars and molars the styles descending on 

 the outer face are strongly developed, those of the premolars being 

 distinctly broader. The protocones (anterior internal columns) are 



Jim 



pm< 



\ 



pm 



\k 



m 



771 



77V' 



Figs. 4-5. — 4, Upper premolars and molars. 5, Lower last premolar and molars. 



Slightly less than natural size. 



large, the length in the case of the molars being equal to one-half or 

 more of the length of the grinding face of the tooth; and each ex- 

 tends well forward of its connection with the antero-median column 

 (protoconule) . The internal face of each column is nearly flat. The 

 anterior internal valley is rather narrow and is furnished with no 

 reentering loop at its anterior end, except that in M 3 there is a very 



