No. 545] 



UXIT CHARACTERS 259 



eephaly are eongenitally altered by environment in the 

 first generation are modified by his statement that this 

 action in bringing diverse head forms together would not 

 go so far as to establish a uniform general type. 



No anthropologist has offered any satisfactory expla- 

 nation as to the adaptive significance of dolichocephaly 

 or brachycephaly. It is well known that these differences 

 of head form are not associated with intellectual ability 

 or mental aptitude. Boas writes (April 8, 1911) : 



generation. 



Apart from the disputed question of the direct influence 

 of environment and of human selection there is absolute 

 unanimity of evidence and of opinion on the one point 

 essential to the present discussion, namely, as to the con- 

 tinuity of allometric variation which establishes different 

 extremes of head form wider conditions of geographic 

 isolation. 



Granted that these extremes evolve continuously, do 

 they become discontinuous in heredity? 



One of the general results of crossing long-headed and 

 narrow-faced types with broad-headed and broad-faced 

 tvpes is what is known as disharmonic heredity, namely 

 that condition in which the face and cranium do not hold 

 together, but broad fares may couple with long skulls, or 



rare 



be no question that the mixture of a long-headed a 

 a short-headed race may lead to disharmomsm, om 

 contributing head form, the other facial expression 

 As to stability or segregation in heredity the latest 



