BY RAYMOND PEARL 



41 



22J 315 4O5 4W 5&5 673 763 

 WINTER EGG PRODUCTION 



855 94^ M45 UiS 



Fia. 4. Diagram of pedigree line D61D168. The significance of lines i& the 

 same as in Figs. 2 and 3, except that the mutant line is double cross hatched.. 

 For the sake of simplicity E495 and the daughters of D31 are omitted in tb 

 1910-11 generation. 



