26 Bulletin American Museum of Natural History. [Vol. XIV, 



Sinopa whitiae {Cope). 



Stypolophus strenuus CoPE, Bull. Hayd. Sur. No. VI, p. 192. 

 Siypolophus whiticB CoPE, Proc. Am. Phil. Soc, Vol. XX, 1882, p. 161 ; 

 Tertiary Vertebrata, p. 292, pi. xxvb, figs. 8-14. 



Wind River assise, Wyoming. This species is somewhat 

 smaller than i^". hians^ and is distinguished from it by the reduc- 

 tion in size of the last lower molar and the more anteroposterior 

 direction of the trigonid shear. In the upper molars the pro- 

 tocone appears to be more compressed and placed further back- 

 ward relatively to the outer cusps, and the metacone of m-3- has 

 entirely disappeared. The species is close to S. agilis of the 

 Bridger, which has the heels of the lower molars more reduced. 

 It is the best known species of the genus and was fully described 

 and figured by Prof. Cope in 1884. 



Nos. 4780 (type), 4781, and 4782. 



c'm^.... 63 c^-mg.... 66 mj-j 22.5 



Sinopa strenua {Cope). 



Prototomus stremius CoPE, Syst. Catal. Eoc. Vert. N. M., Rep. Wheeler 

 Survey, p. 10. 



Stypolophus, Final Rep.Wheeler Survey (U. S. G. S. W. looth Mer.), IV, ii, 

 p. 117, pi. xxxix, fig. II. 



Wasatch assise, New Mexico and Wyoming. Type from New 

 Mexico, in National Museum, Washington. Referred specimens 



