PHYLOGENY. 153 



eutherian mammals, but four have true quadritubercu- 

 lar superior molars. 



I take this opportunity of saying, however, that re- 

 version is not necessarily a result of heredity. It may 

 be simply a retrogression on a line of advance already 

 laid down. What influence lemurine heredity may 

 have had in the case of man, it is not easy to know. 

 But it must be borne in mind that various forms of 

 degeneracy of molar teeth are possible other than the 

 resumption of the tritubercular type, yet the normal 

 reduction generally presented is just this lemurine and 

 primitive eutherian condition. The simplicity of the 

 elements involved, has something, but not everything, 

 to do with this reversion. 



Dr. Paul Topinard has made an investigation 1 of 

 the characters of the crowns of the molars in man, and 

 has reached general conclusions identical with my own. 

 He remarks (p. 665): "It is demonstrated, in conclu- 

 sion, that the teeth of man are, at present, in process 

 of transformation, and that in some future which is re- 

 mote the inferior molars shall certainly be quadri- 

 cuspid, and the superior molars tricuspid. It will be 

 curious to have the statistics as to prehistoric man ; 

 unfortunately, their crania are rare, and their molars 

 generally much worn.' 3 In the details of his examina- 

 tion, there are some divergencies from my results. 

 Thus he finds the quadritubercular second and third 

 superior molar relatively of more frequent occurrence 

 in Europeans than I did. But the absence of Europeo- 

 Americans from his tables reduces the percentage of 

 trituberculars in the Indo- Europeans. He makes no 

 report of Esquimaux. Had he observed this type, he 

 would have found a higher per cent, of tritubercular 



%DAnthro$ologie, 1892^.641 (Nov., Dec.). 



