30 



EVOLUTION OF MAMMALIAN MOLAR TEETH 



PIG. 31. Phascolestes vorax. Upper Jurassic, N. America. Oblique crown view. xj. 



FIG. 32. Phascolestes (Dryolestcs) priscus. Upper Jurassic, America. Internal view. f[ x f-. 



After Marsh. 



FIG. 33. Phascolestes (Dryolestes) vorax. Upper Jurassic, America. Internal view. x-f-. 



After Marsh. 



FIG. 34. Phascolestes (D)'i/olestcs) vorax. Upper Jurassic, America. External view, xf-- 



After Marsh. 



FIG. 35. Asthcnodon. Upper Jui-assic, America. External view. ~ X f. After Marsh. 

 Figs. 31-35. Jurassic Pantotheria or Trituberculata. Lower Jaws. Amblotheriidse. 



