EXPLANATION OF PLATE XXVII. 



Figs. 1, 2. Hipposyus formosus: 



Au upper molar tooth, probably the second true molar of the left side, magnified three 



diameters. 

 Fig. 1. Outer view of the crown. 

 Fig. 2. View of the triturating surface. 



Figs. 3, 4. Washakius insignis : 



Fig. 3. Portion of the right ramus of the lower jaw, containing the last two molars, magni- 

 fied three diameters. 

 Fig. 4. View of the triturating surfaces of the teeth, magnified eight diameters. 



Fig. 5. Hyopsodus minuscueus : 



View of the triturating surfaces of the last premolar and the molars of the left side, magni- 

 fied four diameters. 



Figs. 6-10. Uintacyon edax : 



Fig. 6. Eight side of the lower jaw, containing the intermediate three premolars, part of the 

 first molar, and the second molar, natural size. 



Figs. 7-10. The teeth, magnified three diameters. 



Fig. 7. Triturating surface of the second molar. 

 Fig. 8. Outer view of the same tooth. 

 Fig. 9. Upper view of the premolars. 

 Fig. 10. Outer view of the same. 



Figs. 11-13. Uintacyon vorax : 



Fig. 11. Fragment of the left side of the lower jaw, containing part of the first molar and 



the second molar, natural size. 

 Fig. 12. Upper view of the second molar. 

 Fig. 13. Outer view of the second molar. 



Figs. 14, 15. Mysops fraternus : 



Fig. 14. Eight side of lower jaw, with the last three molars, maguitied two diameters. 

 Fig. 15. View of the triturating surfaces of the molars, magnified eight diameters. 



Figs. 16-18. Paramys delicatior : 



Fig. 16. Lower molar of the right side, the second or third of the series, seen on the tritu- 

 rating surface, magnified three diameters. 



Fig. 17. Upper molars of the same animal, apparently the intermediate pair. Outer view, 

 magnified three diameters. 



Fig. 18. View of the triturating surfaces of the same teeth, magnified three diameters. 



Figs. 19, 20. Micros YO ps (?) 



An upper molar tooth, magnified four times. 



Fig. 19. Outer view. 



Fig. 20. View of the triturating surface. 



Figs. 21, 22. Hyraciiyus nanus ('!) 



A last upper premolar, magnified two diameters. 



Fig. 21. Outer view. 



Fig. 22. View of the triturating surface. 



