Voi,. 6, 1920 
GENETICS: W. E. CASTLE 
75 
the model of the sex-Hnked group of genes. The eight genes fell into a 
curved band lying nearly in one plane, the model being quite flat as viewed 
m r 
FIG. 2 
* 
edgewise. The figure indeed is, as Sturtevant, Bridges and Morgan^ 
said concerning my model of the sex-chromosome Hnkage system, "capable 
