98 Jl. R. Thorpe — John Day Eporeodons 



pointed posteriorly, and projecting to a point nearly 

 above the prostliion ; infra-orbital foramen above middle 

 of P^; lacrymal fossa large and deep; maximum bizy- 

 gomatic diameter anterior to glenoid process ; long high 

 sagittal crest; bullae large, laterally compressed; rami 

 shallow below tooth-row; masseteric fossa shallow and 

 much more vertical than in E. occidentalis; palate 

 produced but slightly beyond W ; posterior narial open- 

 ing shaped like a shallow V. 



In this collection, the species is represented by 60 or 

 more specimens, collected at Turtle Cove, Bridge Creek, 

 Haystack Valley, and at the fossil horse beds on Cotton- 

 wood Creek. 



Measurements of Kolotype* 



mm. 



Total length of skull 247 



Superior molar series, length 52.3 



Superior premolar series, length 45.8 



* This holotype is laterally crushed, and transverse measurements have 

 been omitted, since, even at best, they would be only approximate. 



No. 10145, Y. P. M., is considered a male on account of 

 the longer dental series, much heavier and more robust 

 canines, wider palate and frontals, larger cranium, square 

 muzzle, and, in general, the more pronounced robustness 

 of this skull in comparison with some others of the same 

 species. The paramastoid processes are very heav^^, but 

 the postglenoid tubercles are abnormally small and the 

 position of P^ and P- is oblique. This specimen was 

 collected bv "William Day in 1875 at Turtle Cove. 



Skull Xo. 12408, Y. P. M., from the North Fork of John 

 Day Eiver, is referred to this species, but shows certain 

 differences, as follows: length of molar-premolar series, 

 91 mm., the same as in E. pacificus, but the skull length 

 is that oiE. leptacanthus; totallength of dentition less by 

 3 mm. ; paroccipital processes turned obliquely outward ; 

 sagittal crest shorter ; origin of zygoma heavier and face 

 more prominently divided by the forward prolongation 

 of the zygoma ; nasals wedge-shaped, becoming progres- 

 sively wdder as they advance ; postglenoid tubercles 

 smaller ; molar and premolar series of nearly equal length ; 

 lacr^Tnal fossae more shallow. Specimens numbered 

 12409, 12410, and 12414 exhibit the same characteristics 

 as No. 12408. 



