THE INHERITANCE OF DURATION 175 



Table 21 shows the coefficients for the fraternal in- 

 heritance of six physical characters, cephalic index (the 

 ratio of head length and head breadth) and hair color 

 having been added to those given in the parental table. 

 Again it is seen that the coefficients have all about the 



TABLE 21 



Fraternal inheritance of physical characters in man. (Pearson) 



same values, and it is as apparent as before that the 

 resemblance between brother and sister, for example, in 

 eye-color, or arm length, or shape of head cannot for 

 a moment, because of the nature of the characters them- 

 selves, be supposed to have arisen because of the simi- 

 larity of environment, The average value of all these 

 fraternal coefficients is 



r= .5156 



From these data, with the help of a method due to 

 Pearson, it is possible to determine the percentage of the 



