162 



EVOLUTION OF MAMMALIAN MOLAR TEETH 



pa. mts, 



P?. me. ' 



crista 



A 1 



Jjosffosseffc ,, medifossette 



c r'tsta. 



pa* 



pa* 



ochet 



crochet. 



pa. 



nits. 



c/ng. 



hi'' 



m<* m$<t 



me 1 * 



me^ fn^ 



FIG. 135. Diagram showing typical modifications of the tritubereular pattern in 



Ungulates (cf. Fig. 43). 



