PROBLEMS OF HUMAN DENTITION 127 



symbols of the elements of the first and second dentitions. It 

 is needless to give any further explanation of these formulas, 

 the same having been discussed in detail in the first section. 



In the next formula the rudimentary elements in the molar 

 region of man, described in the foregoing paragraph, the Para- 

 molars I and II — are added. 



ii. h. c. nil. nio. Ml. [Pa,] [Pa„] 

 Ii. L. C. Pi. P.. [P3] M.. M3. |Di] 



This formula represents the construction of a nearly complete 

 humairdentition. In it all elements, really existing or lost dur- 



771 J • 



^,^. 





A3 



%SL.TL 



© Ja.w: 



Figure 21 



ing the last phase of human evolution, are mentioned and ])laced 

 in their natural topographical position. The relation between 

 the elements may perhaps appear still more clearly, by a scheme 

 given in figure 21. In this scheme the lost teeth are made 

 recognizable by dotting. As mentioned, this scheme is not an 

 absolutely complete one; for we know that during the develop- 

 ment of the primate stem, probably in the eocene ancestors of 

 man, an incisor and the first post-canine tooth are reduced 

 and suppressed, three being the primitive number of incisors 



