300 HEREDITY AND ENVIRONMENT 



Fig. 66. X-ray picture of right and left hands each with 

 six fingers (Polydactyly) caused by splitting of the little fin- 

 gers at an early stage. (From Journal of Heredity.) 



HI} 



B A 



Fig. 67. X-ray picture, A of a normal, B of a short-fingered 

 (brachydactyl) hand. (From Bateson.) 



