496 FRETS, THE INDEX CEPHALICUS. 
headbreadth the difference is 0.6 cM. The standarddeviation and 
the coefficient of variation are larger for man than for woman. 
The standarddeviation is larger for the headlength than for the 
headbreadth. The differences between the coefficient of variation 
are slight; they are a little larger for the headbreadth than for 
the headlength. 
These results are opposed to the opinion of TscHEPOURKOWSKY 
(1905, p. 290) that the varieties of the human headform are mostly 
. Owing to the variation of the breadth. 
— Bork (1903, p. 136) finds that with 302 Dutch skulls the modus 
of the length is 182 m.m. and of the breadth 142 m.m. With 50 
adult men Bork finds the mean headlength — 188.6 and the mean 
headbreadth — 154.8 mM; with 50 adult women, he finds Mi = 
1825 and My = 146.6. 
The series of tab. 6 show a 

regular distribution of frequency 



for length as well as for breadth. 
The agreement between actual 




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Diagram 5. Headlength. 933 Men. Diagram 6. Headbreadth. 933 Men, 
Observations. =. Observations. 
REINEM. Normal Curve. ae Normal “Curve: 

and normal distribution is good. (See also diagr. 5—8). 
Of course being collected for familyinquiries, the material 

