A dominant Sex-limited Character. 



15 



type two points are established: first, that the same chromosome 

 X may carry both a recessive (absence) and a dominant character 

 at the same time, and second, that a strong "association" or 

 coupling of characters exists. Thus, when an abnormal red-eyed 

 9 is paired with a normal white-eyed male the offspring are ab- 

 normal red-eyed males and females. These inbred have given 



in the second generation : 



Abnormal red 9 18 



Abnormal red cf 6 



Abnormal white cf O 



Normal red 9 18 



Normal red cf 6 



Normal white cf 14 



A strong tendency for the grandparental combination to 

 reappear in the F 2 generation is manifest. 



The reciprocal cross, viz., abnormal red-eyed cf by normal 

 white-eyed 9 gives abnormal red-eyed females and normal 

 white-eyed males. These inbred have produced : 



Normal white 9 47 



Normal white cf 55 



Abnormal white 9 0 



Abnormal white cf 4 



Normal red 9 34 



Normal red cf 19 



Abnormal red 9 41 



Abnormal red cf 48 



Here also the normal and white combination reappear, wbile 

 the abnormal and white are scarcely represented. 



