50 INHERITANCE. Chap. XIV. 



shell is very rarely seen in a male cat ; the males of this variety 

 being of a rusty tint. 



In various breeds of the fowl the males and females often differ 

 greatly ; and these differences are far from being the same with 

 those which distinguish the two sexes of the parent-species, the 

 Gall us banJciva ; and consequently have originated under domesti- 

 cation. In certain sub-varieties of the Game race we have the 

 unusual case of the hens differing from each other more than the 

 cocks. In an Indian breed of a white colour shaded with black, the 

 hens invariably have black skins, and their bones are covered by a 

 black periosteum, whilst the cocks are never or most rarely thus 

 characterised. Pigeons offer a more interesting case ; for throughout 

 the whole great family the two sexes do not often differ much ; and 

 the males and females of the parent-form, the C. livia, are undistin- 

 guishable : yet we have seen that with pouters the male has the 

 characteristic quality of pouting more strongly developed than the 

 female ; and in certain sub- varieties the males alone are spotted or 

 striated with black, or otherwise differ in colour. "When male and 

 female English carrier-pigeons are exhibited in separate pens, the 

 difference in the development of the wattle over the beak and 

 round the eyes is conspicuous. So that here we have instances of 

 the appearance of secondary sexual characters in the domesticated 

 races of a species in which such differences are naturally quite 

 absent. 



On the other hand, secondary sexual characters which 

 belong to the species in a state of nature are sometimes quite 

 lost, or greatly diminished, under domestication. We see 

 this in the small size of the tusks in our improved breeds of 

 the pig, in comparison with those of the wild boar. There 

 are sub-breeds of fowls, in which the males have lost the fine- 

 flowing tail-feathers and hackles ; and others in which there 

 is no difference in colour between the two sexes. In some 

 cases the barred plumage, which in gallinaceous birds is 

 commonly the attribute of the hen, has been transferred to 

 the cock, as in the cuckoo sub-breeds. In other cases mascu- 

 line characters have been partly transferred to the female, as 

 with the splendid plumage of the golden-spangled Hamburg 

 hen, the enlarged comb of the Spanish hen, the pugnacious 

 disposition of the Game hen, and as in the well-developed 

 spurs which occasionally appear in the hens of various breeds. 

 In Polish fowls both sexes are ornamented with a topknot, 

 that of the male being formed of hackle-like feathers, and 

 this is a new male character in the genus Gallus. On the 



