118 



BUREAU OF AMERICAN ETHNOLOGY 



Height of head (biauricular line-breg7na)" 



[bull. 34 



a Obtained by a spreading and a sliding compass. The branches of a suitable compass d'epais.seur 

 are introduced well into the auditory meati and allowed to rest on their floor. The expansion of the 

 instrmnont is noted, with the scale held over the bregma region; the distance from the bregma region 

 to the lower edge of the scale is measured by the rod of the compas glissi&re, and a simple arithmetical 

 process gives the biauricular hne-bregma height. With practice the measurement becomes easy, rapid, 

 and at least as reliable as the measure of the same height by any other method. With due care, par- 

 ticularly as to the temperature of the instrument, the branches of the compass in the ears cause but very 

 httle discomfort. The writer has used this method for many years with satisfactory results. 



The preceding tables show that the height of the head increases 

 slowly and quite regularly np to full adult age. In nearly all cases 

 it is slightly greater in the Pima than in the Apache, the difference 

 being most marked in the adults. In the several stature groups this 

 measurement is found to be greater also in the males than it is in the 

 females. 



• To summai'ize: (1) It is found that in the Apache and the Pima 

 the three principal diameters of the head increase slowdy and without 

 much irregularity throughout childhood and adolescence until full 

 adult life. In this important phase of development there is no radical 

 difference as compared with the wdiites. 



(2) The proportion between the three diameters differs in the two 

 tribes. The Apache children and the adolescents of both sexes and of 

 all stature groups show less length, decidedly greater breadth, and 

 less height of the head, than the Pima. 



(3) Sex differences in the two tribes are uniform, showing through- 

 out the period of growth and into adult life a slight excess for the 

 males in all the diameters. 



The relation of the three head diameters to one another may be 

 shown to advantage throughout the different stature groups by rep- 

 resenting the measurements in their relation to their mass taken as 

 100, as in the succeeding table. These measurements show how small 

 are the changes in the relative values of the three dimensions through- 

 out a large part of the period of growth. This is manifest also in the 

 indexes calculated from the measurements (see general tables at end 

 of chapter) . 



