466 T. H. MORGAN AND C. B. BRIDGES 



one vermilion factor while her two sex chromosomes carry two 

 vermilion factors. The effects produced by the two sets of con- 

 ditions are the same, and we have found that generally in sex 

 linked characters the effects are equivalent in the two sexes, that 

 is, one sex chromosome produces an effect in the male equivalent 

 to that produced by two in the female. 



Columbia University 

 June 28, 1913 



