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



Among the specific or variable characters in the skeleton are 

 the presence or absence (compare Earle) of the tibiale facet, of 

 the astragalar foramen, and of the articulation of the cuneiform 

 with Mtc. V, which variation is similarly observed in Uintathe- 

 rium, as shown by Marsh. (' Dinocerata,' p. 107.) 



None of the generic characters assigned by Cope to Baf/inunion, 

 Eetacodon, MetalopJiodon and Manteodon appear to the writer to 

 be valid, as they rest either upon errors in field collection or 

 upon individual variations. 



Fig. ig. Coryphcdon rlc/iliaitfopiti, showing flat-topped skull. A, view of occiput ; B, 

 transverse section of crnniuni through region of olfactory lobes, showing air cells. Coll. U. S. 

 Nat. Mus., No. iii. 



Series II. — Large Corvphodons wtih Pjroad, Flat- 

 topped Skulls, Rudimentary Parietal Horns, Triangu- 

 lar Canines. 



12. C. elephantopus Cope. 



Type, U. S. Nat. Mus. Coll. Superior molar 3 ; inferior molar 3. Loc, New 

 Mexico. This type has been temporarily displaced. 



Cotype, No. 11 1, U. S. Nat. Mus. Coll. Skull with upper dentition complete ; 

 inferior dentition and fragmentary jaw. 



Definition. — Superior molars =158 i. Skull characters as in C. testis, except- 

 ing m^^ more quadrate (cotype) with slightly convex mesostyle ; m^ (type) with 

 hypolophid and entoconid 2 ; incisors equal sized. 



Synonyms. 



C. o/>/iij!/i/s Cope. Type, U. S. Nat. Mus. Coll. A single fragiuentary inferior 

 molar. Hypolophid oblique. Entoconid 2 reduced. 



This is a smaller animal than C. testis, but is found u])on a 

 higher level. 



Cope's association of type and cotype is open to some ques- 

 tion. The type has been temporarily lost, and unfortunately the 



