EXPLANATION OF PLATE IV. 



Figures .ill of the natural size. Specimens all from the Bridger tertiary formation of 

 Wyoming. 



FigS. 1-8. PALJGOSYOrS paludosus: 



Fig. 1. A mutilated upper canine of the supposed female, from the samo individual as the 

 specimens of figures 5-8. 



Fig. 2. Mutilated canine of the supposed male, from tho specimen of tho following. 



Fig. 3. A complete series of molar teeth and the mutilated canine of the left side of a fino 

 specimen discovered at Grizzly Buttes hy Dr. J. Van A. Carter. View of tho triturating 

 surfaces, partially worn, of the molar teeth ; from a supposed male. 



Fig. 4. Outer view of the crowns of the same molar series. 



Fig. 5. A complete series of molar teeth, discovered hy Dr. Carter on Henry's Fork of Green 

 River. View of the triturating surfaces; more -worn than in the preceding specimen. 

 From a supposed female. 



Fig. G. Outer view of the anterior two premolars of the same specimen. 



Fig. 7. A third upper premolar, left side. Specimen from Henry's Fork. Hayden's collec- 

 tion of 1870. 



Fig. 8. Lateral view of an upper incisor. Specimen probahly from the same individual as 

 that of Fig. 5. 



Figs. 0-18. Hyrachyus agrarius : 



Fig. 0. Outer view of the crowns of an upper series of molar teeth. 



Fig. 10. View of the triturating surfaces of the same teeth. From a specimen discovered by 



Dr. Carter near the Lodge-pole trail, eleven miles from Fort Bridger. All the teeth con-. 



siderably worn. 

 Fig. 11. An upper second true molar, left side. Found hy Dr. Carter on Henry's Fork of 



Green River. 

 Fig. 12. An upper last premolar, left side, hut little worn. Specimen found hy Dr. Joseph 



K. Corson at Grizzly Buttes. 

 Fig. 13. A portion of the lower jaw; from the same individual as Figs. 9,10. It contains 



part of the lateral incisor, the canine, and the premolars. 

 Fig. 14. View of the triturating surfaces of the premolars, from the same specimen. 

 Fig. 15. Outer view of a second lower molar, from the same individual. 

 Fig. 16. Triturating surface of the same specimen. 

 Fig. 17. An upper canine, found at Grizzly Buttes hy Dr. Corson. 

 Fig. 18. A lower incisor, from the same individual as Fig. 13. 



Figs. 19, 20. Hyrachyus eximius. Specimen found by Dr. Carter on Henry's Fork of Green River. 



Fig. 19. Fragment of the left side of the lower jaw, containing the last premolar and tho 



greater part of the first molar. 

 Fig. 20. View of the triturating surfaces, much worn, of the same teeth. 



