78 THE NEXT GENERATION 



about eight of them. Among these, as the diagram shows, 

 four had short fingers and four had normal fingers. 



Study the diagram and see that in the next generation there 

 were seven short-fingered persons and five that were normal. 



? ? 



9 t 9 cf 



7 9 f ? <? ? 



^9 9? 



IAA 



BRACHYDACTYLISM THROUGH FIVE GENERATIONS 



The family lived in Pennsylvania, and, as Dr. Castle states, " in no case was an ab- 

 normal member of the family known to have married any but an unrelated normal 

 individual." Notice, however, that about half of the descendants were afflicted with 

 brachydactylism. (From " Heredity," by W. E. Castle) 



/--, Male and female respectively, not possessing the trait under 

 consideration. 



A Male and female possessing the trait. 



- 

 Unknown sex, normal or affected. 



Neither presence nor absence of trait can be affirmed. 



(A) Indicates number of children. 



Marriage. 



SYMBOLS USED IN PEDIGREES 

 (As adopted by the Galton Eugenics Laboratory) 



