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that it has been the tirst, so tliat whieli follows immediately on 

 the caninetooth. The two opinions have in common that thej link 

 ont a milk molar and its replacing tootli from the continuity of the 

 tooth I'ow. On account of this the two theories may be distinguished 

 as the excalation theories. I cannot agree with any of these opinions, 

 it appears to me that tlie reduction has been brought about in another 

 way, but this can only be explained more fully,' when I shall have 

 brought forward what pleads for and what against each of the above 

 mentioned theories. 



The Anthropologists look for iheir proof material, or perhaps more 

 exactly for the arguing of tlieir theses in the variations in the set 

 of teeth, which occur with man. Of late Duckworth among others 

 has again drawn attention lo the fact that rudiments of a tooth, more 

 or less developed often appear between the last bicuspid tooth and 

 the first molar tooth especially in the upper jaw and what is especially 

 of importance, often on both sides. These rudiments are conical tooth- 

 points, now occurring single either on the inner or the outer border 

 of the alveolar margin, then again double on each of the two 

 borders simultaneousi}'. And Duckworth does not hesitate to con- 

 sider these rudiments as the again visible traces of the linked out 

 third premolar : "on the whole we think that it is most reasonable 

 to adopt the view that the}- are aborted third premolars, which 

 constitute a human type of dentition similar to that of the New 

 World Apes" '). From the investigation of Duckavorth the following 

 must be mentioned. Firstly that the occurrence of these rudiments of 

 a third premolar is exceedingly different with the different races : 

 in 300 old Egyptian skulls he found no single case, on the other 

 hand in some thirty skulls of Australians he found these rudiments 

 seven times. The set of teeth of the natives of New-Britain shows 

 this anomaly exceedingly often. With respect to the set of teeth of 

 the Anthropoids, Duckavorth mentions that with seven of the thirteen 

 skulls of gorillas, which he investigated, the rudiments in question 

 were present whereas on the other hand he found them not a single 

 time with Hylobates nor with Orang-outans or Chimpanzees. 



The reasoning of those who think that the first milkmolar and 

 pi'emolar, following on the canine tootli have fallen out, in the 

 passing from the platyrrhine form to the catarrhine form is of quite 

 a different nature. It is a tact which is generally acknowledged as 

 being true that originally the number of premolars of the primitive 

 Primates did not amount to three but to four; so that already the 



1) W. H. L. Duckworth. Studies in Anthropology. Cambridge 1904. p. 22. 



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