i8o Sex-limited Inheritance [cii. 



The allelomorphs are 



?, Zi presence and absence of femaleness. 



B, d, presence and absence of the factor for black eye 



The *'pure" green hen is thus S(.$Bb, being, as experi- 

 ment proves, actually heterozygous for the black-eye-factor. 

 The gametes are BZ and b%. 



The pure black-eyed green male is pure in maleness 

 (recessive) and in the dominant black-eye-factor, and his 

 composition is represented thus ZZB^- 



The Cinnamon hen is %Zbb and the Cinnamon cock is 



nbb. 



The matings are then as follows. 



1. Cinnamon pink-eyed $ x black-eyed ^ • 

 composition bb^ $ x BB ^ $ 



/^ black-eyed he?is black-eyed cocks 



Bb^ $ Bb6 $ 



2. Black-eyed ? x Cinnamon pink-eyed S 

 composition Bb^ $ bb $ ^ 



gametes |^ ^° 



F-^ pink-eyed hens black-eyed cocks 



bb<^ 6 • Bb^ S 



3. Pink-eyed $ x black-eyed ^1 S 

 composition bb^ $, Bb ^ $ 



iblack-eyed hens black-eved cocks 



result \^''^ ^ ^^^'^ 



\pink-eyed hens pink-eyed cocks 



\bb^ $ bbSS 



4. Black-eyed 9 x black-eyed F^ ^ 

 composition Bb^ $ Bb $ ^ 



{B$ B$ 



\b^ bS 



black-eyed hens black-eyed cocks 



_Bb^ 6 BBS 6 



\pi7ik-eyed hens and also 



\bb^ $ BbS$ 



This representation is therefore complete except in so 

 far as it takes no account of the production of black-eyed 

 hens together with pink-eyed, which Miss Durham has 

 twice seen in mating (2). These create a definite difficulty 

 which as yet there is no means of overcoming. The con- 

 jecture may be hazarded that they owe their origin to the 



gametes 



result 



