Peterson: Material Discovered in Uinta Basin. 



129 



Genus Hyrachyus Leidy. 



Proc. Acad. Nat. Sci. Philad., 1871, p. 229. 



Hyrachyus is represented by two individuals C. M. Nos. 2908 and 

 3112. The former consists of a pair of lower jaws minus the angle 

 and the incisor teeth, and was found in the upper portion of horizon 

 A, near White River, Uinta Basin, Utah, while No. 31 12 is a fragment 



Fig. 18. Hyrachyus grande sp. nov. Type Carnegie Museum No. 2908. X 3/10. 



of a lower jaw with Pj and My in place and a fragment of the maxillary 

 with only the roots of the premolars present. The latter was found 

 in horizon B, southeast of Kennedy's Hole, Uinta Basin, Utah. 

 While the lower jaws, No. 2908, represent an animal larger than any 

 pertaining to that genus heretofore found, and may probably belong 

 to a new species, or possibly even a new genus, there are unfortunately 

 no characters present indicating any marked advance over those 

 found in the Bridger genus. As stated above, the incisors are lost. 



Fife. 19. I. Hyrachiiys grande sp. nov. Type. Carnegie Museum No. 2908. X 



2/5. 2. Hyrachyus princeps Marsh. M3- of type specimen in Peabody 



Museum of Natural History. X 2/5. 



but from their alveoli it is possible to quite definitely determine that 

 they were all of subequal size, the two intermediates possibly some- 

 what larger than the laterals. The canine is possibly slightly reduced 

 when compared with Hyrachyus agrarius, but this may well be a 

 sexual character and not of specific importance. The premolars are 

 all of the Hyrachyus pattern, with practically no indication of a further 

 9 — DEC. 16, 1919. 



