24 



EVOLUTION OF MAMMALIAN MOLAR TEETH 



Paurodon Marsh. Upper Jurassic* (Como), Wyoming. Some approach 

 toward these distinctive characters is made by Achyrodon of the Amblo- 

 theriidie (Stylacodontidffi), from early members of which family Paurodon 

 may have descended. Fig. 26. 



4. Family Diplocynodontidw Marsh. 



Upper Jurassic. Upper molars with large crushing protocones ; 

 lower molars with very broad basin-shaped talonids. 



Diplocynodon, Upper Jurassic* (Como Beds), Wyoming. Fig. 20. 

 Docodon, Upper Jurassic* (Como Beds), Wyoming. Fig. 21. 

 Enneodon, Upper Jurassic * (Como Beds) Wyoming. 



3. 



ILLUSTRATIONS OF THE CHIEF TRICONODONTA AND TRITUBERCULATA. 





FIG. 4. The types of the British inesozoic mammals, representing the natural size. 

 1. Amphilestes. 2. Amphillterium. 3. Phascolothcrium. 4. Triconodon mordax. C. Peramus. 7. 

 Spalacotherium. 8. Peralestcs. 9. Pcraspalax. 10. Leptocladus. 11. Amblotherium. 12. Phus- 

 colestes. 13. Achyrodon. 14. Stylodon. 15. Athrodon. 10. Bolodon. IS. Plagiaulax minor. 10. 

 Stereognathus. 



FIG. 5. Amphilestes. Lower Jurassic, England. 

 Internal view, enlarged. 



Fia. 6. Phascolotherium. Lower Jurassic. 

 England. Internal view, enlarged. 





Fro. 7. Iriconodon (Triiicanthodon). Upper Jurassic, England. External view, enlarged. 



* See note on page 22. 



