


FRETS, THE INDEX CEPHALICUS. 519 
of the changes which both undergo when the capacity of the skull 
increases or decreases”. 
For the same length-, resp. breadthclass the Scottish material 
is more dolichocephalic than the Dutch. From the results of 
Boas it appears that for the same length- or breadthclass the 
Indian material is a little less dolichocephalic than the Dutch 
and the Scottish. Herein the headindex manifests itself as a race- 
character. 
Similar results have striked ORENSTEEN (1921). He writes (p. 17) 
„the coefficients of correlation resulting from the length and the 
breadth of the head vary much from one race to another. The 
Significance of this variability is suggestive and the writer accordingly 
undertook another investigation.” 
As results of grouping the material in lengthclasses, resp. in 
breadthclasses we find: 
1. With men and with women a long head is relatively more 
dolichocephalic than a short head. 
2. A broad head is relatively more brachycephalic than a 
narrow head. 1 and 2 follow from the principle of compensa- 
tional growth. 
3. In the same lengthclass women are more dolichocephalic 
than men. 
4, In the same breadthclass women are more brachycephalic 
than men. 3 and 4 are a sex-character. 
5. The differences between the indices are in the breadthclasses 
larger than in the lengthclasses. 
6. In the same length- resp. breadthclass Scottish people are 
more dolichocephalic than Dutch, Indian more brachycephalic. 
This difference is a race-character. 
That, as JOHANNSEN says, indices may not without more be compa- 
red with each other is evident from the above conclusions. So for 
our material we found that the index of the female is a little 
higher than of the male (p. 492). From the tables 14—17 it appears 
that this may follow from the small headlength of the female 
(p.518), for in the same lengthclass the headform of woman is 
somewhat more dolichocephalic than of man. The same was found 
by JOHANNSEN for the Swedish and for old Egyptian material. So, 
comparing indices, it is necessary to know also the length of the head. 
