296 



University of California. 



[Vol. 2. 



mentions two species of Merycocltcerus, Gomphotherium cameloides , 

 Elolherium humeroswn, and Mesohippus prcestans, as characteristic 

 of the upper division, while Diceratherium is the typical form of 

 the lower division. 



Dr. W. D. Matthew has recently shown that the John Day 

 Oreodons referred to Merycochcerus are generically distinct from 

 Leidy's type. Dr. Matthew has kindly furnished the following- 

 note, in which it is shown that these species should be included in 

 a new genus, for which he has proposed the name Paracotylops: — 



Merycochcerus Leidy. 



Type, M. 

 (Leidy). 



proprius 



Premaxillcz coossified 

 along their entire inner 

 margins. 



Nasals much reduced. 



Infraorbital foramen 

 above m. I— - 



Face suddenly narrowed 

 in front of orbit<. 



Zygomata greatly ex- 

 panded. 



Mastoid process greatly 

 expanded into a broad 

 transverse plate. 



Occiput broad and short, 

 sagittal and transverse 

 crests nearly buried 

 in cellular tissue. 



Cellular bony tissue 

 extensively developed 

 on posterior part of 

 skull'. 



Neck verv short. 



Paracotylops new 

 genus. 



Type P. (Oreodon, Mery- 

 cochcerus) superbus 

 (Leidy). 



Premaxillcr coossified 

 at tips. 



Nasals unreduced. 



Infraorbital foramen 

 above p. 4 111.' 



Face more gradually nar- j 

 rowed in front of orbits. 



Zygomata greatly or 

 moderately expanded. 



Mastoid process of mod- 

 erate size. 



Occiput high and narrow, 

 sagittal and transverse 

 crests very prominent. 



Little or no cellular bony 

 tissue on posterior part 

 of skull. 



"Neck rather 

 (Scott). 



short ' 



Eporeodon Marsh. 



Type E. occidentalis 

 (Marsh). 



Premaxillcr not coossi- 

 fied. 



Nasals unreduced. 



Infraorbital foramen 

 above p. 3 



Face gradually narrowed 

 in front of orbits. 



Zygomata moderately 

 expanded. 



Mastoid process not ex- 

 panded. 



Occiput high and narrow, 

 sagittal and transverse, 

 crests prominent. 



No cellular bony tissue 

 on posterior part of 

 skull. 



Neck of moderate length. 



Owing to the change in the name of the characteristic fossil of 

 the Upper John Day, the writer suggests that this division would 

 more appropriately be denominated the Paracotylops beds. 



In correspondence regarding the relation of his classification on 



