662 THE BRIDGEE EPOCH. 



Specimen No. 2 is young, as the last molar is not protruded beyond 

 the apices of the cross crests. 



Both specimens were found by myself in the Bridger basin on Cot- 

 tonwood Creek, Southwest Wyoming. 



ITyrachyus EXiMius, Leidy. 



Hayden's Geo). Survey Montana, 1871, p. 361. Annual Report U. S. Geol. Survey Terrs., I, p. 6C, 1873; 

 Plate IV, figs. 19-20. Cope, Proceeds. Amer. Philos. Soc, 1873, p. 213. 



Plates XXIIIa, fig. 1; LIII, fig. 3; LIV; LV; hVa; LVIIIa; figs. 5-6. 



This tapiroid left numerous remains in the sediments of the lakes of 

 the Bridger epoch. I obtained parts of numerous individuals during my 

 exploration in the Bridger basin during the summer of 1872, but did not 

 obtain any fragments which I could refer to it, from the Washakie basin, 

 whose deposits are supposed to be of the same age. The most character- 

 istic specimens are: (1) An almost entire specimen, which lacks only the 

 muzzle and skull anterior to the glenoid cavities, one fore-leg, and the 

 caudal vertebrae; (2) Both mandibular rami with the atlas and axis; (3) 

 The palatal part of a cranium with worn molar teeth; (4) A ramus man- 

 dibuli with four posterior molars, all but the last in good preservation. 



The skeleton first enumerated is an unusually complete fossil, and has 

 served as a basis of estimation of the generic characters of Hyracliyus. It 

 was discovered by myself standing erect in the side of a blufi" at an angle 

 in its escarpment. The entering face of the precipice cut off the nose 

 of the specimen, which stood with regard to the topography like the winged 

 bulls of the ruins of Nineveh. I occupied much time in removing it from 

 its ancient position, and it is now mounted in a life-like attitude in my 

 collection. 



Cranium. — In the specimen to be described, the anterior portion from 

 the glenoid cavities is wanting. The sagittal crest is quite elevated, and 

 the lateral occipital quite prominent, and continuous below with the 

 superior margin of the squamosal portion of the zygoma. Four nutri- 

 tions foramina pierce the parietal bone near its middle and above the 

 paraoccipital process, and two enter the squamosal above the postglenoid 

 process. The paroccipital process approaches near the occipital condyle 



