266 DOUGLASS — FOSSIL MAMMALIA 



is very large. The supraorbital foramina are farther apart than in Oreodon culbertsoni. 

 The orbit is circular. The forehead is convex between the orbits, but concave in front of 

 the stephanion. The brain-case is broad, full, and well rounded out. There arc no distinct 

 ridges near the parietotemporal sutures. The anterior part of the sagittal crest is low. 

 The brain-case here is full and arched upward. Back of this the crest is broken away, 

 but evidently it was not high and narrow, as in Oreodon culbertsoni or the so-called 

 Eporeodon of the White River or John Day. It appears to have been more like that of 

 0. gracilis. The foramen magnum is large. The basioccipital in front of the condyles 

 is broadly convex, then for a short space forms a rounded (not a, sharp) angle, then is 

 broadly convex again between the tympanic bullse. The bullse are large, but not so large 

 as in Eporeodon (?) major. They are quite evenly rounded and longer antero-posteriorly 

 than transversely. Posteriorly they abut against the paroccipital processes, which extend 

 backward and outward. These processes are convex postero-internally and deeply con- 

 cave antero-exteraally toward the bases. The post-glenoid processes are moderately 

 thick. The posterior nares open between the posterior parts of the last molars. 



The horizontal rami of the mandible are widely separated just behind the symphysis 

 as in Eporeodon, but the caniniform premolars are very much nearer together and are 

 nearly circular in section. The angle descends below the horizontal ramus. The coro- 

 noid process is narrow at its base and the condyle is a short distance behind it, making 

 the sigmoid notch and the upper part of the mandible narrow antero-posteriorly as com- 

 pared with Eporeodon (Princeton Col., 10580). The upper molars have very prominent 

 outer horns to the crescents. 



This animal resembles both Oreodon gracilis and Eporeodon, which perhaps form a 

 different line from that of 0, culbertsoni, but the latter is so variable and the validity of 

 Eporeodon is so doubtful that I will not attempt the task of making comparisons. Even 

 if Eporeodon is a valid genus this animal is quite different, and I prefer to use the older 

 name Eucrotaphus. 



Found in Toston beds in Broadwater county. 



Measurements. 



M. 



Length of skull from anterior of P* to posterior of occipital condyles 158 



Length from back of last molar to back of condyles 080 



Width of skull at middle of orbits 104 



Width of postorbilal constriction 035 



Width of brain-case, greatest 055 



Width of condyles 038 



Width of foramen magnum 021 



Width of palate at last molars 040 



Length of paroccipital processes 027 



