PEOBLEMS OF HUMAN DENTITION 107 



111 the foregoing the rehitioii between the denture of the two 

 groups of Primates and the progress of the primitive toward 

 the higher form is explained in a manner differing from that 

 commonly accepted. But I believe that my conce})tion has 

 many advantages. That others are more simple and my theory 

 more complicated, I admit. But even this complication corre- 

 lates several facts of a diverse nature explaining them in a very 

 logical manner, and this, I believe, increases the scientific char- 

 acter of my hypothesis. Upon this ground I base the accurac}^ 

 of the \'iews which I have expressed regarding the manner in 

 which the human denture evolved from that of an ancestor with 

 a ])latyrrhine denture. Perhaps other investigators, acquainted 

 with other facts relating to the odontology of Primates, are able 

 to supply still more arguments in favor of this theory. 



SECOND PROBLEM: TO WHICH DENTITIOX DO OUR .MOLARS 



BELONG'' 



The next problem is one confined to the molar region of our 

 denture, the subject of this discussion being the question to 

 which dentition our molars belong, to the first or milk dentition 

 or to the second or permanent dentition. 



Opinions do not agree as to the dentition to which our molars 

 belong. Three theories have been advanced. One group of 

 investigators is of the opinion that the molars belong to the 

 first or milk dentition, being therefore elements of the deciduous 

 set without a successional tooth. Another group of authors 

 believe they belong to the second or permanent dentition, being 

 consequently elements of this set without predecessors. And 

 a third group of morphologists asserts that our molars belong to 

 both dentitions, each molar being the result of the fusion of a 

 tootli of the first dentition with a corresponding one of the sec- 

 ond. I treat the problem in a somewhat different manner. In 

 the foregoing section I tried to demonstrate that our first molar 

 was originally a milk molar. I therefore feel sure that this 

 tooth belongs to the first dentition, and I am treating the pres- 

 ent problem immediately after that of the evolution of our 

 denture, because in the course of this section, I shall deal with 



THE AMKUICAN JOURNAL OV ANATOMV, VOL. 19, NO. 1 



