SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOL. 59 
The mutual relation of the three main diameters, however, does 
not remain the same from the lowest to the highest heads. With the 
height it is as 110.4 m the latter to 100 in the former, but with the 
breadth similar proportions are only 104.2 to 100, and with the length 
103.5 to loo. Hence, the highest heads are not only highest abso- 
lutely, but also relatively to head length and breadth. The length 
has evidently lagged behind even slightly more than the breadth (C. I. 
in lowest heads 74, in highest 74. 6) , but the difference is small and 
within the possibilities of accidental. 
The above conditions do not fall, it seems to the writer, in the 
category of simple compensations ; they are more likely directly 
connected with the anatomical peculiarities of the vault of the skull 
and are expressions, in the main, of the law of expansion of the skull 
in the directions of lesser resistance. 
Cephalic Module 
The sum of the length, breadth and height of the head, divided by 
three, gives the mean diameter of the head or the cephalic module, 1 
Cm. 14 14.5 15 15.5 16 16.5 
PERCENT* 
OF CASES 
-20 
\ 
C.M 
15 
10 
\ 
FIG. 5. Curve showing the distribution of cephalic module (mean diameter 
of the head) among 150 adult males of the Kharga Oasis. 
which, for comparative purposes, represents the size of the head 
1 The term " modulus " was first employed by E. Schmidt, who designated 
by it (in Archiv f. Anthrop., Vol. 12, i87Q-'8o, p. 179, and in his " Anthropolo- 
gische Methoden " Leipzig, 1888, p. 212 et seq.) the mean of the three diame- 
ters of the skull. 
