( '85) 



so the niilkmolars and premolars of man should be the original 2'"' 

 and S'-J. 



According to the theory, mentioned in the second place, the for- 

 mula becomes : 



I. 1. 2. C. 1. P. 0. 0. 3. 4. 



i. 1. 2. c. 1. m. 0. 0. 3. 4. M. 1. 2. 3. 



i. 1. 2. c. 1. m. 0. 0. 3. 4. J/. 1. 2. 3. 

 J. 1. 2. C. 1. P. 0. 3. 4. 



so that with man the original 3"^ and 4''' milkmolar and premolar 

 would still exist. 



The last mentioned opinion seemed to me also to be the most 

 acceptable. It pleads for it, that in a phylogenetically older stadium 

 the first milkmolar and its premolar had already become lost, and 

 if then one lets the second follow, the reduction-process is localized 

 and more continuity brought into it. The following can moreover 

 be said against the opinion of the Anthropologists, that the fourth 

 milkmolar and premolar with man should have been lost. It may 

 be justly supposed that only those teeth can reduce, which fulfill 

 the smallest function. And this now does not applj* to the last milk- 

 molar and premolar. On the contrary. With the Platyrrhines we see, 

 that just that last molar does not only not stay behind by the others, 

 but is even the sti-ongest developed of the three. So with those 

 forms, where we might with some right suppose at least some indi- 

 cation to a reduction of this tooth, we on the contrary find a pro- 

 gressive development. No single reason can be given why in the 

 middle of this toothrow a tooth should suddenly ha\e disappeared, 

 and w4iy a discontinuity of the set of teeth should have come about 

 by which the function would have suflfered considerably, no single 

 indication can be found, neither in the ontogenetic nor in the full- 

 grown set of teeth, in the form of a diastem, that a tooth Jias really 

 become lost here, and so the first mode of explanation : that the 

 last milkmolar and its replacing tooth would have become lost, does 

 not seem probable to me. 



But neither can the theory that at the passing from the platyrrhine 

 to the catarrhine type, the first milkmolar with the premolar belonging 

 to it, should have been linked out, satisfy me. The above mentioned 

 argument about it, is always only an argument per analogiam 

 without its being possible that a morphological proof for such a 

 reduction can be given. If the sets of teeth of Platyrrhines are com- 

 pared in particular with relation to the degree of development of 

 the first premolar nothing is found that points to a reduction of this 



