0. C. Marsh — Cretaceous Mammalia. 91 



EXPLANATION OF PLATES. 



PLATE IT 



Figures 1-4. — Upper molar tooth of Cimolomys gracilis, Marsh. 

 Figures f-8 — Upper molar of Cimolodon nitidus, Marsh. 

 Figures 9-12. — Upper molar of Nanomys minutus, Marsh. 

 Figures 13-15. — Last upper molar of Dipriodon robustus, Marsh. 

 Figures 16-18. — Upper molar of Dipriodon lunatus, Marsh. 

 Figures 19-21. — Upper molar of Tripriodon ccelatus. Marsh. 

 Figures 22-24. — Upper molar of Selenacodon fragilis. Marsh. 



PLATE III. 



Figures 1-3. — Upper incisor of Halodon sculptus. Marsh. 

 Figures 4-6. — The corresponding tooth of Halodon serratus, Marsh. 

 Figures 7-10. — Outer upper incisor, probably of the same species. 

 Figures 11-13. — Fourth lower premolar of Halodon. sculptus. 

 Figures 14-17. — Third or fourth lower premolar of Halodon serratus. 

 Figures 1 8-20. — Lower incisor of Tripriodon caperatus, Marsh. 

 Figures 21-23. — Lower incisor of Tripriodon ccelatus. 



PLATE IV. 



Figures 1-3. — Upper molar tooth of Didelphodon vorax, Marsh. 

 Figure 4. — Lower molar of Didelphodon ferox, Marsh. 

 Figures 5-7 — Lower molar of Didelphodon compius, Marsh. 

 Figures 8-1 i. — Lower molar of Gimolestes curtus, Marsh. 

 Figures 12-15. — Lower molar of Gimolestes incisics, Marsh. 

 Figures 16-19. — Upper premolar of same species. 

 Figures 20-22. — Upper premolar of Didelphodon compius. 

 Figures 23-25. — Upper molar of Pediomys elegans, Marsh. 

 Figures 26-28. — Canine tooth of Didelpjhodon ferox. 



