R. C. PUNNBTT AND THE LATE MaJOR P. G. BaILEY 45 



of blues. It is true also of many breeds where the feathers exhibit a 

 definite pattern such as most of the barred, pencilled ^ laced, and 

 spangled breeds. In the last case it is true whether the spangled 

 feather is predominantly light with a black tip, as in Hamburghs, or 

 predominantly black with a light tip, as in Anconas. It is true also of 

 Brown-breasted Game. On the other hand there are breeds in which 

 the colour differences between the sexes are not limited to the sexual 

 feathers. This is the case in Black-reds and in Silver-greys, where 

 we find a marked difference between the black breast of the cock and 

 the salmon-coloured one of the hen. The difference also occurs in the 

 abdominal and leg feathers, which are brown mossed in the hen'^ but 

 black in the cock. In Piles also we find the breast colour difference, 

 the salmon breast of the hen contrasting with the white one of the 

 cock. A sexual colour difference, apart from the sexual feathers, is found 

 also in certain of the laced and pencilled breeds, such as Indian Game, 

 Partridge Cochins, and Partridge Wyandottes. In the case of these 

 breeds, it is important to remember that the cock is either a black-red 

 or a duckwing. 



We are inclined to think that there is an essential difference between 

 the breeds of the first group where the colour difference is restricted 

 to the sexual feathers, and those of the second where the sexes exhibit 

 a colour difference apart from the sexual feathers, and to suppose that 

 the sexual colour differences are present in the second group, but are 

 obscured by some dominant factor. The obscuring factor we consider 

 to be a different one in different cases. In whites it is the inhibitor for 

 colour that occurs in the dominant whites, such as Leghorns^ ; in blacks 

 and blues, it is due to the factor for black ; in brown breasted, there is 

 also some factor leading to increased melanism ; in buffs and light golds 

 there is probably a factor which inhibits melanic pigmentation. 



In the absence of such obscuring factors, we have the condition 

 found in the second group with its marked sexual dimorphism in colour. 



In the first group it is clear that " hennification " would lead to the 

 production of males which in colour, as well as in feather structure, 

 resemble the hens. Provided that the cock is fully henny, he will be 

 coloured like the hen. Now, as we have already pointed out, the hetero- 



1 The amount of melanic pigment is throughout much reduced in the cocks of pencilled 

 breeds, but such as exists exhibits the same arrangement as in the hen. 



2 In writing this we had in mind the Brown Leghorn and the Silver-grey. In wheaten 

 hens the Salmon tint is found also over the abdomen and thighs. 



3 In recessive whites of course the obscuration is brought about through the absence of 

 some factor essential to pigment production. 



