10 MUSEUM BULLETIN NO. 9. 



The molar and bicuspid teeth in many instances present 

 a very remarkable appearance. This is, in the case of the upper 

 set, evidence of wear mainly on the lingual side, in the lower, 

 mainly on the labial. Taking, for instance, a first 

 molar that has been in use many years and is much worn 

 down, the resulting shape is very peculiar. In the case of an 

 upper tooth, a sharp high edge is present on the outer or labial 

 margin, while on the lingual or inner margin the worn crown 

 slopes sharply away from this edge, sometimes, indeed, right 

 down to the alveolar border. An opposing lower tooth from 

 such a skull would show a wearing away in exactly an opposite 

 direction, although never to such a pronounced degree as in the 

 upper tooth. Of the molar teeth, the first is usually the most 

 advanced in this condition, the second and third less so, as one 

 proceeds backwards. The second bicuspid also shows a high 

 degree of this oblique wear, the first rather less, the canine 

 scarcely any at all, its worn surface being more or less flat, 

 while the surface of the incisors is usually flattened also. This 

 appearance is not peculiar to the teeth of the Eskimo. I have 

 noted it in certain American Indian skulls in particular, two 

 skulls from the interior of British Columbia and one from 

 Ontario and it is quite possible that it may be found in skulls 

 from other regions or races where local conditions of diet, methods 

 of mastication, and palatal shape, combine to produce conditions 

 similar to those found among the Eskimo. For among the 

 Eskimo this oblique wear of the teeth seems to be of quite 

 common occurrence. It is probably due, I think, to the crushing 

 and grinding chewing movements of their jaws combined with 

 the broad horseshoe palate typical of their race. The deviation 

 forwards and sideways of their mandibles in the process of chew- 

 ing must be extensive and carried out with their biting muscles, 

 powerful as we have seen them to be, in a high state of contrac- 

 tion in order to assist in crushing and grinding the food in pro- 

 cess of mastication. The result probably is that in the forward 

 and sideward movements of the mandible and this more es- 

 pecially in the case of a palate of typical horseshoe form 

 the outer margins of the centre-lateral teeth of the lower set are 

 brought into hard grinding contact with the inner sides of the 



