x] 



The Silky Fowl 



185 



Now if femaleness be a dominant factor and can repel 

 D, forming a spurious allelomorphism with it in the way 

 sue gested for the case of Abraxas grossulariata x lacticolor 



o o <^ 



and the Canaries, a system would be provided which would 

 fulfil all the chief conditions marked out by the experimental 

 data. 



Taking then the following allelomorphs, the occurrences 

 in the three matings which have given clear results may be 

 represented in a tabular form. 



, J, presence and absence of femaleness, a dominant 

 factor without which the zygote developes into a 

 male. 



P, p, presence and absence of the black pigmentation. 

 D, d> presence and absence of a factor which can sup- 

 press or mask the development of P. 



i. 



composition 



Silky 

 PPdd% 



x Brown Leghorn $ 

 ppDD J 



females slightly 

 pigmented 



2. 



composition 



composition 



Brown Leghorn 



males slightly 



pigmented 

 PpDd$ $ 

 x Silky < 

 PPdd $ 



females deeply 



pigmented 

 Fpdd<% $ 



males slightly 



pigmented 

 PpDd& $ 



composition 



Brown Leghorn ? x 



PpDd$ 



Females 



Males 

 pD $ . PD 



offspring 



According to this analysis one bird in eight, namely the 

 female marked *, will be of the deeply-pigmented type. 



ceived. It would, however, fail to represent the i deeply-pigmented $ in 

 8 birds from Brown Leghorn $ x P 1 <$ , and would increase the expectation 

 to 2 $ in 8 birds, and this is negatived by the results of experiment. 



