EXPLANATION OF PLATE XXVI. 



PigS. 1-8. UlNTATHBRIDM ROBUSTUM : 



Fig. 1. View of the right side of a mutilated cranium, one-half the diameter of nature. Spec- 

 imen upon which the genus was characterized. Discovered by Dr. Carter about fifty miles 

 from Fort Bridger. 



Fig. 2. An atlas, of the same species. Inferior view, one-fourth the diameter. 



Fig. 3. A right humerus. Found by Dr. Carter in the same locality as the specimen of Fig. 1. 

 Anterior view, one-fourth the diameter. 



Fig. 4. Proximal extremity of a femur, probably pertaining to a larger species of the same 

 genus, or perhaps to a larger variety. One-fourth the diameter. 



Fig. 5. Distal extremity of another femur, probably of U. robustum. One-fourth the diameter. 



Fig. 6. Calcaneum of the left side. Upper view, one-half size. 



Figs. 7, 8. Astragalus, one-half size. 



Fig. 7. Upper view. Fig. 8. Inferior view. 



Figs. 9, 10. Hyrachyus eximius : 



Left lower penultimate molar tooth, natural size. 

 Pig. 9. Outer view. Fig. 10. Upper view. 



Fig. 11. Hyrachyus nanus : 



Eight ramus of the lower jaw, retaining the back four molar teeth. Natural size. 



