258 



THE DENTAL SYSTEM OF THE PRIMATES [SECT. A 



PREMOLAR TEETH. 



Additions to the premolar series of the Katarrhinae might be 

 expected a priori, in view of the prevalence of three premolar 

 teeth in the Platyrrhinae and lower Primates. Yet although an 

 additional premolar tooth seems to be not uncommon in the 

 Hominidae (Magitot, op. tit., records a striking instance of super- 

 numerary premolar teeth in the skull of a negro), such examples 

 are rare among the Katarrhinae in general. De Terra 1 gives no 

 instance of the kind. Yet, ajDart from complete accessory or 

 supernumerary teeth in the premolar region, small dental masses 

 (scarcely worthy of being described 2 as teeth) also appear occa- 

 sionally in the crania of Simiidae and Hominidae. They are often 

 seen between the second premolar and the first molar teeth in the 

 upper jaw. 



A good instance is the peg-like tooth shewn in Fig. 189 in the 

 skull of a Chimpanzee. In the skull of a Gorilla, small dental 

 masses occur in similar positions, as in that shewn in Fig. 193, 

 where one small mass intervenes between the last premolar and 

 first molar teeth, while a second occupies a corresponding place 

 between the two premolar teeth. These 

 masses are rare in the mandible whether 

 of the Simiidae or Hominidae. In the 

 former, the Gorilla provides the greatest 

 number of examples, while among the 

 Hominidae the crania of natives of 

 Melanesia furnish more instances than 

 any other group I have been able to 

 examine 3 . Two examples from such 

 crania are given in Figs. 190 and 191 ; 

 it will be noted that in one case the 

 dental masses are symmetrical, while 

 in the other the anomaly occurs on 

 one side only. The view that these 



1 Beitrage zu einer Odontographie der Menschen-Rassen. Inaugural Dissertation, 

 Zurich, 1905. 



2 Windle (J.A. and P. Vol. xxi. p. 84) distinguishes very appropriately between 

 "supernumerary" imperfect teeth and "supplemental" teeth of size commensurate 

 with those adjacent to them. 



3 Cf. Duckworth and Fraser, Proc. Camb. Phil. Hoc. 1900. 



Pn3t.Pn3.flcc.Deo!. Mas. 



Fig. 193. Left upper teeth of 

 a young Gorilla : accessory den- 

 tal masses are situated between 

 the first and second premolar 

 teeth, and between the second 

 premolar and the first molar 

 tooth respectively. (W. L. H. D. 

 priv. coll.) 



