96 



M. R. Thorpe — John Day Eporeodons 



Museum of Natural History. I msh also to express 

 my thanks to Professors Schuchert and Lull for their 

 helpful criticism and suggestions, as well as to Miss 

 LeVene for her very careful and efficient aid in editing 

 this and other papers. The illustrations have been made 

 by Mr. Eudolf Weber. 



Description of Species. 

 Eporeodon occidentalis (Marsh) 1873. 



(Figs. 1-3.) 



Holotype, Cat. No. 10142, Y. P. M. Upper Oligocene (middle John Day), 

 Bridge Creek?, John Day Eiver, Oregon. Plesiotype, Cat. No. 12345, 

 Y. P. M., from Turtle Cove, John Day Eiver, Oregon. 



Fig. 1. — Eporeodon occidentalis (Marsh). Holotype. Eight lateral view. 

 X3/5. 



Specific characters. — Bull^ large and laterally com- 

 pressed; skull mesocephalic and about the same length 

 as that of Merycoidodon {0 reodon) culbertsonii; lacrymal 

 fossa large and deep, but confined to lacrymal bone ; post- 

 orbital constriction of medium diameter; biz^^gomatic 

 diameter large ; sagittal crest low and short ; infra- 

 orbital foramen above middle of P^ ; masseteric fossa 

 deep and nearly horizontal; coronoid process thin and 

 much higher than the condyle; paramastoids slender; 

 posterior nares V-shaped ; palate not produced beyond M^. 



Specimen No. 12316, Y. P. M., possesses natural casts 

 of the bullee which are divided into anterior and posterior 

 hemispheres. In this collection there are about 50 indi- 



