Kathleen V. Ryley and Julia Bell 
409 
breadth*. As the total size of the skull varies much from race to race it seems 
desirable to compare the mesodacryal chord with another horizontal measure and 
we have taken the minimum forehead breadth : see Table, p. 408. 
It will be seen that the Negroes stand at one end of the list and the Indo- 
Europeans at the other, but again the change of index is relatively small, and it 
may be legitimately doubted whether it would be visually significant. 
(7) On the relative Racial Variability of the Nasal Bridge Characters. 
Tables XIII and XIV give respectively the Standard Deviations and the 
Coefficients of Variation of the characters determined in such series as supplied 
sufficient data for even an attempt at these constants. There is no doubt in our 
minds that the coefficient of variation is the better measure for racial purposes in 
the case of absolute measurements. We will consider first what points arise from 
a discussion of the variability of the mesodacryal subtense, chord and arc from this 
standpoint. The relative orders of variability are given in Table XV. 
Again beyond the broad fact that the apes on the whole are far more variable 
than the races of men, perhaps little can be learnt from this table. In the 
apes the female is more variable than the male in 5 out of 9 cases ; the same 
ratio of 5 to 4 is maintained in the case of the negro races ; in the lower races 
from Borneo and the Veddahs, the males are more variable than the females in 
the ratio of 5 cases to 1, while in the higher races — Egyptian and English — the 
ratio is 5 cases of the female to 1 case of the male more variable. Altogether 
therefore the female is more variable in 16 and the male in 14 cases. . Generally 
there is no evidence for greater male variation in these coefficients of variation 
of the mesodacryal absolute lengths. Even if we based our comparison on the 
absolute variations of the mesodacryal characters, we find among the apes the 
male is more variable in 5 the female in 3, with one case — the Chimpanzee 
mesodacryal subtense — of equality ; in the lower races (Veddahs and Borneo) 
the male is more variable in all 6 cases ; in the negro races in 5 out of 9, but 
in the higher races (English and Egyptian) in only 1 out of 6 cases. Thus in 
absolute measurement the male is more variable in 17, the female in 12 cases. 
* The reader must not judge from Figs. 6 — 9 of the contours, pp. 428 — 9. These all have the meso- 
dacryal chord in considerable excess of the negro mean, and were selected to give approximately mean 
angles, not mean absolute lengths. 
