6o 



INHERITANCE IN POULTRY. 



and 4 have flat feathers. Assuming frizzling to be dominant, non-frizzling 

 recessive, and that all my Frizzle fowls are heterozygous, we should expect 

 50 per cent frizzled offspring. The result accords well with these hypotheses. 

 None of the hybrids show any trace of silkiness. Silkiness is recessive as 

 against non-silkiness. 



This result is striking and has been observed by others. Tegetmeier 

 (1867, p. 224) bred Silkies to other varieties and found that " the chickens 

 produced seldom had the silky feathers, but were clothed in plumage of the 

 ordinary character." Mating these hybrids together he got among plain 

 feathered offspring " one covered with feathers like those of the Silk fowl," 

 but with black plumage. Darwin (1876, Chapter VII) had previously bred 

 a white Silk hen to a Spanish cock ; "none inherited the so-called silky 

 feathers." 



6. NUMBER OF TOES. Thirty hybrids gave the following distribution of 

 characteristics : 



Here, as elsewhere in this paper, the inheritance of extra toe is difficult to 

 account for on the Mendelian principle of dominance. 



7. SKIN COLOR. All hybrids have a black skin. Tegetmeier (1867, 

 p. 224) got the same result. 



8. CREST. So far as noted, all mature hybrids have a well-marked crest, 

 but it is somewhat smaller than that of the Silky. 



CONCLUSIONS. 



A final conclusion as to dominance must await the production of the second 

 generation of hybrids. The following (in italics) appear to show Mendelian 

 dominance over the corresponding allelomorphs : 



Rose comb vs. Single comb. 



Frizzle feathers vs. Plain feathers. 



Black skin vs. White skin. 



Crest vs. Plain head. 



Plumage color and number of toes are unit characters, but behave pe- 

 culiarly. The dominance of the crest is imperfect. 



