101 M. R. Thorpe — John Day Eporeodons 



species in the Marsh Collection from the John Day basin, 

 was fonnd at Turtle Cove on the John Day River by 

 William Day in 1875. It is of middle John Day age. 



Eporeodon huUatus (Leidy) 1869. 



Three sknlls, Nos. 10146, 11056, and 12299, Y. P. M., the 

 two former from Turtle Cove and the third from Bridge 

 Creek, are tentatively referred to this species. In tooth 

 measurements they correspond to the t}^e, but the 

 scarcity of other measurements of the type and the lack 

 of drawings make it impossible to be sure of the identifi- 

 cation. 



Leidy compared the type with Oreodon cidbertsonii, 

 which he said it closely resembled, except for the presence 

 of large auditory bullae. These three skulls from the 

 John Day basin are much more robust than the White 

 River 0. cidhertsonii, and possess a much greater bizygo- 

 matic diameter. No. 11056 is more robust than No. 12299, 

 and may be a male. It is also individually older. 



These skulls tend toward brachycephaly, as in E. occi- 

 dentalism and, with the exception of the latter species and 

 E. trigonocephalus, they exhibit this trend more distinctly 

 than any other species from the basin. The lacr^mial 

 fossae are relatively small and shallow, the nasal bones 

 wide, the postorbital constriction narrow, the sagittal 

 crest moderately long, the bulla about the size of that in E. 

 occidentalis, the palate moderately produced posteriorly 

 beyond LP, the palate wide, the canines heaw and more 

 robust than in the other species of this locality. In No. 

 10146 the premolars are crowded so that both P^ are set 

 obliquely; this is true also in No. 12299, but not to so 

 great a degree. 



Eporeodon condoni, sp. nov. 



(Figs. 6-8.) 



Holotype, Cat. No. 11016, Y. P. M. Upper Oligocene (middle John Day), 

 Bridge Creek, John Day Valley, Oregon. Collected by L. S. Davis in 1874. 

 ParatyiDes, Cat. Nos. 11029 and 12294, Y. P. M., from Haystack Valley and 

 Turtle Cove respectively. 



Specific characters: — Somewhat smaller than E. paci- 

 ficus and more brachycephalic ; length of molar and pre- 

 molar series approximately equal; bullae small and less 

 compressed, about the same size as in E. occidentalis; 



