COUPLING 95 



are other breeds in which the barring is sHghtly diffe- 

 rent in pattern but the fundamental colour the same : 

 black. Such breeds are frequently described as 

 " silver." Another fundamental colour is buff or gold, 

 and barred breeds whose fundamental colour is gold 

 are frequently described as " golden." In Belgium 

 there are two similarly barred varieties of fowl, the 

 silver Campine and the gold Campine. When silver 

 males are mated with gold females, the progeny are 

 all silver, but, when gold males are mated with silver 

 females, the males are all silvers while the females 

 are all golds. Thus another pair of factors is related 

 to each other precisely as those for barring and non- 

 barring are related. Black, the fundamental colour 

 in silver, is dominant to buff or gold, the fundamental 

 colour in golden ; and, of the factors for the latter, 

 one is free while the other is coupled with that for 

 femaleness. 



Still another pair of factors is revealed by these 

 Belgian varieties. In both varieties, both sexes are 

 barred, but not equally, for, while the hackle-, rump- 

 and tail-feathers are barred in the hens, the same 

 feathers are not usually barred in the cocks. Male 

 chickens barred like the females are occasionallj'^ hatched, 

 but are not retained by the Campine breeders. 



Since the hens are always completely and the cocks 

 not always incompletely barred, it is clear that the 

 hens must carry both factors, that the factor for com- 

 plete barring is dominant, and that it is coupled with 

 femaleness. It is also clear that the completely barred 

 cocks occasionally thrown must be sons of such hens 

 as are sometimes found carrying a second untied factor 

 for complete barring. Thus the usual constitution of 



