562 PROCEEDINGS OF SECTION F. 



It would be wrong, however, to lead one to suppose that the subject 

 of teeth in the aboriginal is connected solely with man's affinities with 

 the monkeys and apes. It goes really much further. It raises questions 

 about the origin of heterodont teeth and the formation of the cusps of 

 the premolars and molars. 



Works on dentistry — I speak of the best and the recognised standard 

 works — give clear and precise and plausible descriptions of the method 

 in which bicuspid and molar teeth are built up from the primitive 

 simple conical forms by aggregation or fusion. Many give no hint or 

 suggestion that there may be any other theory on the subject. It 

 should be mentioned, however, that there is a good deal of evidence 

 in favor of the view that the primitive molar of the mammals was a 

 single simple cone, and that the present forms have arisen by successive 

 additions of cusps to this cone. Some teeth that I have described in 

 a communication to the Journal of Anatomy and Physiology, written 

 at Professor AVatson's instigation, show very instructive relations 

 between cusps and those peculiar structures known as enamel tumors, 

 which have been aptly described by Salter as " submerged cusps " ; 

 and it is very interesting to find that one of the finest of these specimens 

 is the tooth of a kanaka that I brought from New Caledonia. 



In another specimen described in the same communication the 

 cingules of two fused central incisors have developed a cusp-like growth, 

 strongly suggestive of the cusp-accretion theory, while the form of the 

 roots of a canine seems to 3deld strong support to the fusion-of-cones 

 theory. 



I must refer in this connection to some extraordinary milk teeth 

 in a young aboriginal subject. The milk molars beyond the crowns 

 are ballooned to an enormous extent, and an examination of the fangs 

 and the portions that are becoming fangs gives rise to a question as 

 to whether the roots of these milk molars are not being developed by 

 a process of plication of a primary simple tube. 



An observation bearing on the structure of the teeth may be 

 mentioned here. The lower jaw of an aboriginal from the Coorong 

 had been exposed to sunlight and great heat, with the result that the 

 teeth are " weathered " and split up into what may be termed their 

 component parts. A " part," often, though not invariably, is seen 

 to consist of a root and its directly superimposed cusp. 



In a paper sent to the Royal Society of Edinburgh I have dealt 

 with some aspects of the dentition of aboriginals. I may record one 

 observation here, however, since it illustrates a statement made by 

 Burchard {Dental Pathology and Therapeutics, 2nd Edn., p. 230) to the 

 effect that " An excessive growth of hair upon the face and body has 

 also been associated in some cases with a deficiency in number and 

 alteration in form of the teeth. In other cases no abnormality was 

 noticeable. In some cases the hair and other dermal structures may 

 be normal and the teeth be quite deficient in number." Other instances 

 have been noted by Topinard (Anthropology, p. 162), who refers in this 

 connection to the influence of heredity. 



