W. Batkson and R. C. Punnett 195 



were deeply pigmented, while of the 362 $ $ 82 were deeply pig- 

 mented, a proportion approximating fairly closely to the expected 

 quarter. We should add that owing to a deficiency of pure Brown 

 Leghorns some of the hens used were light-shanked brown birds of 

 Brown Leghorn extraction. With regard to the transmission of pig- 

 mentation these 4>ehaved similarly to the pure race. 



(^) ^1 ? (unpigmented) x Brovm Leghorn ^. 



[Nature of mating, FfPpIi xffppll.] 



Two -F, $ $ of this nature were crossed with a Brown Leghorn (^ 

 and gave 26 j/'j/' and 18 $ $ of which none were deeply pigmented. 

 This again fits in with our hypothesis (cf Fig. 4), for no deeply 

 pigmented birds are to be looked for from this mating. 



4. fj X Fully pigmented (PPii) birds, 

 (a) F,^xPPii%. 



[Nature of mating, FfPPii x ffPpIi.] 



The expected result from this form of mating is equal numbers, in 

 both sexes, of chicks with deep pigmentation and of chicks with some 

 pigmentation. We have made this mating twice with the following 

 results : 



TABLE VL 



* Hales Females 



Full pig- Some pig- Full pig- Some pig- 

 Reference Nature of matiiig mentation mentation mentation mentation 



1906 Pen 33, 349 Silky ?xFi<r 5 2 3 5 



1909 „ 17, 114 i- 2 fall pig- ? X F, <r 20 18 19 22 



Total 25 20 22 27 



Expectation 235 235 23-5 23'5 



These results are obviously in close accord with expectation, but it 

 must be mentioned that $ 114 also gave one $ chick recorded as 

 without pigmentation. 



()8) jPi % {slightly pigmented) x Silky ^. 



[Nature of mating, %^PpIi x ^^PPii.] 



Since on the hypothesis the gametes produced by the Fi% are %Pi, 

 %pi, (^PI, and ^pl it follows that all the female chicks will contain 

 P without /, while of the male chicks all will be heterozygous for / 

 while half will be homozygous for P. La discussing the nature of the 



Joum. of Gen. i 14 



