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 centro-lateral teeth of the lower set are 
brought into hard grinding contact with the inner sides of the 
