W. Bateson 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 behaved similarly to the pure race. 



i/S) F^ ^ {unpigmented) x Broivn Leghorn ^. 



[Nature of mating, FfPpIixffppIL] 



Two i^i $ 5 of this nature were crossed with a Brown Leghorn ^ 

 and gave 2(5 (/"(/' 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. f 1 X Fully pigmented (PPii) birds. 



(«) F,^xPPii%. 



[Nature of mating, FfPPiixffPpIi.] 



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 



Males Females 



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

 Reference Nature of mating mentation mentation mentation mentation 



1906 Pen 33, 349 Silky ? x Fj <f 5 2 3 5 



1909 „ 17, 114 F, full pig. ? X Fi <? 20 18 19 22 



Total 25 20 22 27 



Expectation 33-5 :i3-3 33-5 33-5 



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

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

 without pigmentation. 



{13) Fi ^ {dighthj pigmented) x Silky ^. 



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



Since on the hypothesis the gametes produced by the F^ $ 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. In discussing the nature of the 



Journ. of Gen. i 14 



