90 EVOLUTION OF MAMMALIAN MOLAR TEETH 



lobe " including our hypocone, metaconule and metacone. All subsequent 

 authors in France follow this system, which indeed works well for one 

 group. But what we need now is a system which will apply not only to 

 all groups of ungulates, but to unguiculates as well, so that when we 

 reach the upper Cretaceous borderland between unguiculates and ungulates 

 we can employ the same set of terms and the same basis of description. 



1 can only conclude by expressing the conviction that the tritubercular 

 theory of Cope rests upon such conclusive evidence* that its universal 

 adoption as the key to the interpretation of all molar teeth cannot be long 

 deferred. It is one of the chief anatomical generalizations of the present 

 century. 



[The Bibliography given in the foregoing article is here omitted. See Biblio- 

 graphy at end of volume. ED.] 



* See pp. 2-26, 227. 



