EXPLANATION OF PLATE IV. 



Figures all of the natural size. Specimens all from the Bridger tertiary formatiou of 

 Wyoming. 



Figs. 1-8. Pal/EOsyops paludosus: 



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



specimens of figures 5-8. 

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

 Fig. 3. A complete series of molar teeth aud the mutilated canine of the left side of a fine 



specimen discovered at Grizzly Buttes by Dr. J. Van A. Carter. View of the 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 by Dr. Carter ou Henry's Fork of Green 



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



From a supposed female. . 



Fig. G. Quter 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 coUec- 



tiou of 1870. 

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



that of Fig. 5. 



Figs. 0-18. Hyrachyus agrarius : 



Fig. 9. 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 by Dr. Carter on Henry's Fork of 



Green River. 

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



K. Corson at Grizzly Buttes. 

 Fig. 13. A iJortion 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 by Dr. Corson. 

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



Figs. 19, 20. Hyeaciiyus exijiius. 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 tirst molar. 

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



