102 



A MANUAL OF MENDELISM 



early in winter at the rate of about three a week, and 

 those that begin later but at a higher rate. If this be 

 so, then there are four different groups of hens, two of 

 which are inseparable, as judged by their total winter 

 eggs only. And, if the factor which either of these 

 groups carries be a dominant whose recessive is carried 

 by hens laying no winter eggs, then, under ordinary 

 circumstances, the usual two-pair set should be produced: 



X 

 Y 



Over 

 30 eggs 



X 



y 



X 



Y 



Under 

 30 eggs 



X 



y 



No winter 

 eggs 



But, with the tied and untied factors, there should be 

 hens of six different constitutions and cocks of nine, 

 as follows : 



Hens 



MM MM MM MM MM MM MM MM MM 

 XX XX XX Xx Xx Xx XX xx xx 

 YY Yy yy YY Yy y y YY Yy yy 



Unfortunately no observations have been made by 

 which the suggested division among the medium laying 



