

FRETS, THE INDEX CEPHALICUS. 509 
CRAIG (1911) calculates from data of Douaras Derry that for 
Egyptian material the headindex has to be multiplied with 0.976 
to get the skullindex. So the reduction is for his material about 2 
units The divergent results depend on the great variability and 
the rather few observations and for this kind of inquiries also on 
personal equation. 
For the determination of the capacity of the skull from the 
headmeasurements there are several methods. LEE (1901) gives 
formulae for this determination when the skulllength and the skull- 
breadth are only known. In the absence of the measurement of the 
height of the skull much stress may not be laid of course on such 
determinations. 
To find the skullmeasurements 11 mM. have to be deducted 
from the headmeasurements in accordance with LEE (from obser- 
vations of WELCKER). I use the statements of GLADSTONE (1905) 
which rest on many observations and find: 
L, = 193.4 — 7.86 = 185.54 mM.; B, = 154 — 7.84 = 146.16 mM. 
L, = 183.6 — 7.32 = 176.28 mM. and B, = 148 — 7.43 = 140.57 mM. 
For C,„ = 6 752 L + 11.421 B — 1434.06, the calculation gives C,, = 
1488 and for C, = 13.555 L + 5.562 B — 1842.61, C, = 1485 cM3. 
For C,= 7.884 L + 10.842 B — 1593.96, we find C, = 1320 and for 
C; = 9.084 L + 7.21 B — 1288.10, C, = 1327. According to the formels 
of LEE for our material the mean capacity of the male skull is 
1485 cM3. and for the female 1325 cM3, 
MACDONELL (1901) making use of the same formula but diminishing 
the headmeasurements with 11 mm. to get the skullmeasurements, 
calculates the capacity of the skull of 3000 English criminals = 
1378 and for 1000 Cambridge students = 1431 cm5. (see also 
PEARSON and LEWENz 1903). 
Bork (1903) by aid of the experimental method, filling the skull 
with water, finds for the mean capacity of 255 Dutch skulls M — 
1382.1; Mod = 1400; smallest capacity — 1025, largest capacity 
= 1796 (Skulllength, mod — 182 mm., skullbreadth mod = 142 mm). 
Most of the persons that I have examined are inhabitants of 
the provinces Z.-Holland and Zeeland. I have gathered (tab. 13) 
the persons that are born in Zeeland and whose parents and grand- 
parents are born in Zeeland too. The same I did for the islands of 
Z.-Holland and for Rotterdam. These are small numbers. The 
