boas] THE CEPHALIC INDEX 453
II
We will apply this result to a discussion of the correlation between length and breadth of head. Pearson ! has calculated the following data :
Adult Male Crania : r
Ancient Egyptians (Flinders-Petrie) 0.2705
Bavarian peasants (Ranke) 0.2849
Modern Parisians (Broca) 0.0474
I have calculated the coefficients of correlation for the following series :
r
Sioux, living, 243 adult males + 0.24
Skulls of 57 adult male Sioux Indians 9 -j- °- 2 4
Skulls of 47 adult male Eskimo, Smith sound *. . . + °-47 Indians of the northern coast of British Columbia ;
adult males + 0.08
Shuswap Indians ; adult males + 0.04
Skulls of adult males, Baden * + 0.09
Bagdi caste of Bengal ; adult males * -f- o. 13
It appears from these data that the degree of correlation between length and breadth of the head is very slight, and that its values differ considerably among various races. The latter fact is rather surprising, since we might expect that in the human species the same organs are subject to the same laws. The coefficient of correlation in the Parisians, for instance, is exceed- ingly low, in fact so low that we may say that the breadth of head in the Parisians is entirely independent of the length of head.
The most plausible explanation of this phenomenon lies in the effect of mixture of types upon the coefficient of correlation.
1 Loc. cit., pp. 279, 280.
4 George L. Otis, List of Specimens in the Anatomical Section of the U. S. A. Medi- cal Museum, 18S0, pp. 104 ff.
3 Ibid., pp. 9 ff.
- Die Schiidel in der Grossherzoglichen Anatomischen Anstalt zu Heidelberg;
Archiv fiir Anthropologic, vol. 24, pp. 24 ff.
5 H. H. Risley, The Tribes and Castes of Bengal, vol. I, pp. 16 ff.
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