BREEDING 



141 



at all, with a high-producing hen which presumably carries 

 Li. The mating may be represented as follows: 



Parents 



X XL 



XO 



It may be seen here that although the dam XLiO is a 

 high producer, her daughter XO cannot inherit that high 

 production. 



There are two further facts concerning the inheritance 

 of fecundity not indicated above which must be considered. 

 The first is that mediocre production (which we may repre- 

 sent by Li), may be inherited by either sons or daughters, 

 from either or both sire and dam. That is to say, though 

 the female-producing ovum never carries L2, it may and fre- 

 quently does carry Li. Inasmuch as the spermatozoa and 

 male-producing ova may also carry it, its inheritance is not 

 in any way limited. The second fact is that the presence of 

 Xi is essential for the full realization of the influence of Lj. 

 If ii is not present, L2 acts like Li, that is, it produces only 

 mediocre laying. If Li is present, L2 seems to build upon it 

 as a foundation. By way of illustration, let us suppose two 

 cases. First, that a hen which is a mediocre producer, giving 

 off Li in both kinds of ova (XLiOLi), is mated with a male 

 carrying Z2 in half of his spermatozoa, but not carrying Li at 

 all; second, that the same male is also mated with a mediocre 

 producer giving off ii only in her male-producing ova {XLiO). 

 If we consider only the female offspring, the two cases may 

 be illustrated respectively as follows: 



Male 

 Parents (Xl) (x 



Daughters XL^ OL^ X OLi 



Parents 



Daughters 



XL. 0X0 



