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

 15. Coryphodon hamatus Marsh. 



Type, Yale Museum No. 1330. Skull and dentition much worn. 

 Cotype, Yale Museum No. 1334. Female skull with perfect superior and in- 

 ferior dentition. Log. , Evanston, Wyoming. 



Synonym. 



18. CorypJiO(ion{Mattteodon)siibquadratus CoY>e.. Type, No. 4340, Am.Mus., 

 Cope Coll. Superior molar 2, incisors and fragmentary premolar. Loc, Big 

 Horn, Wyoming. 



Definition. — Size large. Superior molars with quadrate crowns and well 

 developed hypocones upon mi and m2. Inferior molars with nearly trans- 

 verse crests; m^ without entoconid 2. 



This species was mistakenly associated with C. elepliantopiis 

 by Earle. In size it equals C. testis, but it is well distinguished by 

 the quadrate form of the superior molar teeth in which, according 

 to the figures of Marsh (Dinocerata, Fig. 55, p. 52), a representative 

 of the hypocone is present. This is developed from the ridge 

 extending backwards from the protocone, In the inferior molar 

 teeth the crests are nearly transverse, and there is no trace of the 

 entoconid 2. 



The unique quadrate tooth with a prominent hypocone, type of 

 Manteodo7i snbquadratiis (Fig. 15), was without reason considered 

 by Cope as a third superior molar. It proves, upon comparison 

 with Marsh's cotype made by Dr. Matthew, to resemble a second 

 superior molar of C. hamatus. It differs, however, from C. hama- 

 tus in the more distinct development of the posterior spur of the 

 metacone crescent, a character which may subsequently prove 

 to give it distinct specific rank. 



The type skull of C. hamatus is somewhat fractured. The top 

 of the skull of the cotype, a female, is considerably narrower than 

 that of C. testis, female, presenting a condition intermediate 

 between that of C. testis and C. armatus. The canines in this 

 animal, as in other females, are small. 



28. Coryphodon singularis, sp. nov. 



'type, A hind limb, tibia, fibula and pes No. 2980. Loc, Wind River, Wyo. 



A small and unique hind foot and limb from the Wind 

 River Beds, found upon the level of C. wortmani, is 6i excep- 



