32 



HEREDITY OF SKIN COLOR IN NEGRO-WHITE CROSSES. 



F. DISCUSSION OF INHERITANCE OF TRAITS ASSOCIATED 



WITH SKIN COLOR. 



I. Eye Color. 



As a by-product, our data afford an answer to the question : Does 

 the inheritance of eye color in black X white crosses follow the same 

 rule as that already established for eye color among whites ? The data 

 collected on eye color have been analyzed. From, the fact that the 

 fraternities studied were a highly selected lot (viz., chiefly offspring of 

 hybrids), certain matings, e.g., blue X blue, are absent or rare. In 

 table 30 "hazel" means an eye that has brown pigment only in a nar- 

 row band around the pupil, the rest of the iris being blue; "green" is 

 blue with yellow pigment, but with brown pigment practically or 

 absolutely lacking; "yellow hazel" or "yellow brown" implies the 

 presence of 3'ellow added to the other type of pigmentation; "light 

 brown," "dark brown," and "black" are applied to various degrees of 

 development of the melanic pigment over the whole area of the iris. 

 Table 30 is arranged in increasing order of pigmentation of the parents. 



Table 30. — Distribution of eye color in offspring of parents zvith given amount of iris 



pigmentation. 



(A) PARENTS HAZEL X HAZEL. 



«Bl.,blue; Gr., green; Lt. br., light brown; M.br., medium brown; D.br., dark brown; Y. h., yellow-hazel 



