PKOKLEMS OF Hl'MAN DENTITION 109 



ture. Henco T ])()ssess a great amount of anomalous material 

 for the study of human dentition. The su})jeel of my first 

 research concerned the supernumerary elements in th(> molar 

 region of man. This research disclosed facts heretofore unknown, 

 leading me to a standpoint with regard to the morphological 

 significance of our molars which is entirely opposite to that once 

 held l)y me. 



My collection of supernumerary elements in the molar region 

 of man, enal.)les me to confirm a well-known fact, viz.: the extra- 

 ordinary rarity of a so-called fourth molar in the lower jaw of 

 European man, for among this extraordinarily large quantity' 

 of skulls, I have found not a single specimen of this anomaly. 

 In his odontograjihy of human races de Terra mentioned only 

 three cases as having yet been described in literature. 



In critically examining all the cases of a so-called fourth 

 molar described by different authors, it is evident that under 

 this name supernumerary teeth of a very different nature are 

 included. The comparison of all additional elements in the 

 molar region of man has made it clear to me that it is incorrect 

 to denominate as fourth molars each supernumerary tooth in 

 this region. There are, to distinguish sluuply, two species of 

 su}Dernumerary teeth in this part of the denture. In the first 

 group the additional element is situated immediately behind 

 the third molar, prolonging the row of the teeth in a very 

 regular manner. Sometimes it inclines a little to the lingual side 

 of the axis of the dental arch, a point to which we shall return later 

 on. In the second group the supernumerary tooth is situated 

 at the buccal side of the dental arch, either in the corner l^etween 

 the second and third molar, or in that between the first and 

 second. 



Do these two groups of supernumerary teeth represent identi- 

 cal anomalies having the same anatomical significance? If only 

 a small number of l)oth types were to hand, it would be a \'erv 

 diflficult nuitter to give a decided answer. The abundant mate- 

 rial collected by me, enables me to ha\'(^ a definite opinion about 

 this matter. I feel sure that the sui)ernuinerary teeth are not 

 identical in all of these groups, and that they have a \aried 



