128 



EVOLUTION OF MAMMALIAN MOLAR TEETH 



FIG. 78. Upper teeth of Hyopsodv.s marshi from the Bridger Formation, Middle Eocene. Note 

 the quadrate contour of the molars, the well-developed intermediate conules and hypocone. 

 (The opposite dental series converge too much in the figure.) (Cf. Figs. 77, 79.) 



X|. 



FIG. 79. Lower teeth (crown view) of Hyopsodus Icmoinianus, from the Wasatch Formation, 

 Lower Eocene. Note the absence of the paraconid, the presence of a well-developed postero- 

 median cusp, the hypoconulid on m lt z 3 . (Cf. Figs. 77, 78.) xi. 



TTL 3 



FIG. 80. Teeth of Diaeodexis (Hyopsodus) laticuneus, a genus now referred to Hyopsodv.s. 

 From the Wasatch Formation, Lower Eocene, xf. 



