140 



PROF. DR. L. BOLK 



III Homo: Normal state 



ii io c mi mo Mi [PaJ [Pan] 

 Ii lo C Pi F, [P3] M, :\l3 [Di] 



IV Homo: First phase of reduction 



ii io c mi m2 Mi [PaJ [Pa„] 



Ii I, C Pi P, [P3] M, [DiJ [DiJ 



V Homo: Second phase of reduction. Final state 



ii io c nil Ml M2 [PaJ [Pa„] 



Ii [I2] C Pi [P.,] [P3] M3 [DiJ [DiJ 



A brief synopsis of all transformations and reductions in the 

 developmental history of the dentition of Primates is given in 

 the three following simplified formulas, the first dealing with the 

 dentition of one of the Cebidae, the second the dentition of 

 man in its actual state and the third that of the future construc- 

 tion of human dentition after my conception. The first of these 

 runs as follows: 



the second 



the third 



I. I. C. P. P. P. M. M. M. 



I. I. C. P. P. M. M. M. 



I. C. P. M. M. M. 



After this summarizing account of my views as to the direction 

 in which the evolution of human dentition is progressing, I now 

 present arguments supporting the probability of the accuracy 

 of this conception. The fundamental point in it is the relation- 

 ship maintained between the reduction of the hindmost molar 

 and the evolution of the second milk molar. Our first task is 

 to furnish the necessary evidences of this latter evolution. 



As already mentioned the common view with regard to a per- 

 sisting milk molar is that from some cause or other this tooth 

 could not be shed, either because of lack of space, or an 

 anomalous position of the second premolar in the jaw. This 

 explanation is entirely erroneous. I do not pretend that in other 



