204 Bulletin American Museum of Natural History. [Vol. X, 



occurs in the higher levels of Buffalo Basin, Wyoming. Our 

 scanty evidence therefore appears to indicate a retrogression in 

 size in this series, but this is an inference by no means certainly 

 established. 



DS. pa. rr, 



F'ig. 22. CorypJiodon testis. Superior nmlar series, male (Am. Mus Coll. No 274); inferior 

 molar series, female (Am. Mus. Coll. No. 2868). 



17. C. lobatus Cope. 



Type, Nat. Mus. Coll. Sup. molar 3 ; inf. molar 3 ; part of sup. and inf. 

 canine, indeterminate. 



Definition. — Sup. molars=i93;. Inf. molars=ig6^. Dental characters 

 as in C. testis, e.\cepting elongation of protoloph and degeneration of posterior 

 metacone crescent in m^-. Astragalus usually lacking astragalar foramen. 

 Cranium massive, with widened parietal horn rudiments. 



Syiii'iiyiiis. 



20. CorypJiodon anax. Type : No. 4327, Am. Mus., Cope Coll. Superior 

 molar 3 ; inferior molars, premolars and incisors. Loc, Big Horn, Wyoming. 



25. C. (Bat/iiiioiton) pachypus Cope. Type : No. 4335, Am. Mus., Cope 

 Coll. Astragalus, calcaneum, pelvis, femur, &c. Indeterminate type. Loc., 

 Big Horn, Wyoming. 



This is the largest Coryphodon known ; it surpasses C. testis in 

 size, the ratio being 50 : 45, as indicated by the femora. 



Unfortunately the name C. lobatus is prior to the more appro- 

 priate C. a/iax, awdi must supersede it. The lower molars defined 



