PLATE XX. 



Fig. 21. PfiOCAMELUS (?) 



A first or second upper molar of tho loft side, view of the triturating surface. Spocimon 

 found in association with those of Fig. 14, 15, and 17, in Washington County. 



Fig. 22. Astragalus of the left side, upper view, probably of the same species as the last, and found 

 with it. 



Fig. 23. HlPPARION(f) PAKVUI.US 



A coronary bone, or second phalanx, of the natural size. Found at Antelope, Nebraska. 



Fig. 24. Feus Augustus? 



Distal extremity of the right humerus, front view, one-half size. Specimen found on the 

 Niobrara River, by Professor Hayden. 



Figs. 25, £6. Hyraciiyus agrarius. From a specimen obtained by Dr. Carter at Grizzly Buttes. 

 Natural size. 



Fig. 25. Left ramus of the lower jaw, containing the back two premolars and the two suc- 

 ceeding molars. 



Fig. 28. View of the triturating surface of the same teeth, with the addition of part of the 

 second premolar. 



