FERTILITY AND HATCHING OF EGGS. 



145 



Zt 35 II 

 Cock e ' 



70 

 ■fs 



Fig. 14. Diagram showing the relation between fathers' aver- 

 age pen records of infertiHty, and the average infertihty of their 

 daughters' eggs. The solid line gives the average per cent, of 

 infertile eggs shown by the females mated with each male. The 

 dotted line gives the average per cent, infertile for the family of 

 daughters corresponding to each father. 



given for example in the last columns of Tables VII and VIII) 

 and the percentage of eggs infertile and of fertile eggs hatched 

 shown by the daughters of this male bird in the next season's 

 breeding? To answer this question would obviously be to apply 

 somewhat the same test to inheritance in the male line as we have 

 to inheritance in the female line. It is impossible, however, to 

 apply this test at present because of lack of sufficient material. 

 The number of male birds whose daughters appear as breeders 

 the second year is so small as to make a determination of corre- 

 lation coefficients a waste of time on account of the magnitude 

 of the probable errors which would be involved. It is possible, 

 however, to get some little light on the matter in an indirect 



