12 



CALVIN B. BRIDGES 



a rise in the other two. More data on the same case is furnished 

 by a triple experiment, which involves as the other locus, bar, a 

 dominant mutant descr bed by Tice (Biol. Bull. '14). 



These data (table 15) add four cases of rise to the three given 

 by table 14, and a corresponding four cases of fall to the two 

 from the same source. The value for bar fused shows three 

 cases of fall and five of rise. For the pair vermilion bar the 

 cases stand four against four. The totals in everj^ case show 

 practically no change (table 16). 



The section from cherry to forked includes nearly all of the 

 known sex-chromosome, and for this whole distance there is 

 no change in the totals, and the females are balanced two against 

 two (table 17). In this last case, that of cherry and sable, the 

 slight change is a fall in the amount of crossing-over. 



TABLE 14 

 Pi wild 9 9 X vermilion fused cfcf. Fi wild type 9 X Fi wild type cfcf 



