STURTEVANT 



73 



TABLE 4 



TABLE 5 



TABLE 6 



TABLE 7 



B 

 O 

 P 



R 

 393 



crossing over has in pulling down the 

 .observed per cent of cross-overs in the 

 case of BM and (C, 0)M. Whether or 

 not this effect is partly counter-bal- 



anced by triple crossing over must 

 also remain unsettled as yet. Work 

 now under way should furnish an- 

 swers to both these questions. 



Table 8 

 (The meaning of the phrase 'proportion of cross-overs' is given on p. 68) 



BO. P^: gray eosin $ X yellow red $ 



Fj: gray red $ X gray eosin $ 

 Fo: 9 $,g.r. 241,g.e. 196 



$ S, g.r. 0, g.e. 176, y.r. 195, y.e. 2 



Proportion of cross-overs, -j—- 



BP. P^: gray red 2 X yellow vermilion $ 

 F^: gray red $ X gray red 3 



