282 



ANTHROPOLOGICAL SURVEY IN ALASKA 



[ETH. ANN. 40 



Eskimo Crania : Percentage Relation of the Basion-Nasion Diameter to 

 Mean Cranial Diameter (Cranial Module) 



/ BNX100 \ 

 V CM J 



BOTH SEXES TOGETHER IN ASCENDING ORDER 



Southwestern and midwestern Northwestern 



Pilot Station, Yukon 65. 6 



Chukchee 66. 



Little Diomede Island 66. 1 



Hooper Bay 66. 4 



Nelson Island 66.7 



Togiak 66.9 



Southwest Alaska 67. 3 



Indian Point, Siberia 67. 4 



Mumtrak 



Nunivak Island 



Pastolik 



St. Michael Island 



St. Lawrence Island: 

 Male 



67.4 



67.6 



67.6 



68.0 



67.2 



Female.- (69.6) 



Wales 67. 7 



Point Barrow 67.8 



Point Hope 68.1 



Barrow 68. 4 



Old Igloos 69.0 



Shishmaref 69. 2 



Northern Arctic and northeastern 



Baffin Land 67. 4 



Hudson Bay 67. 6 



Smith Sound (male) 67. 6 



North Arctic 68.1 



Greenland 68. 5 



Southampton Island 68. 7 



PROGNATHISM 



Since better understood, the subject of facial prognathism has lost 

 much of its allure in anthropology; yet the matter is not wholly with- 

 out interest. 



Facial protrusion is as a rule secondary to and largely caused by 

 alveolar protrusion, which in turn is caused by the size and shape of 

 the dental arch; and the dental arch is generally proportional to the 

 size of the teeth. The form of the arch is, however, quite influential. 

 With the teeth identical in size a narrow arch will be more, a broad 

 arch less protruding, and a narrow arch with small teeth may pro- 

 trude more than a broad one with larger teeth. Another influence 

 is that of the height of the upper face, the same arch protruding more 

 in a low face than in a high one. And still another factor is the in- 

 cline of the front teeth, though this affects merely the appearance of 

 prognathism and not its measurements. 



There are different ways of measuring facial prognathism, and 

 with sufficient care all may be effective; I prefer, for practical 

 reasons, linear measurements from the basion, which, together with 

 the facial and subnasal heights, give triangles that can readily be 

 reconstructed on paper and allow a direct measurement of both the 

 facial and the alveolar angle. The three needed diameters from 

 basion are taken, the first to the " prealveolar point." or the most 

 anterior point on the upper dental arch above the incisors ; the sec- 

 ond to the "subnasal point," or the point on the left (for con- 

 venience) of the nasal aperture, where the outer part of its border 

 passes into that which belongs to the subnasal portion of the maxilla 



