Chap. VIII. SEXUAL SELECTION. 281 



to reappear in the offspring at the same advanced age. 

 When deviations from this rule occur, the transmitted 

 characters much oftener appear before than after the 

 corresponding age. As I have discussed this subject 

 at sufficient length in another work, 19 I will here merely 

 give two or three instances, for the sake of recalling the 

 subject to the reader's mind. In several breeds of the 

 Fowl, the chickens whilst covered with down, the young 

 birds in their first true plumage and in their adult plum- 

 age, differ greatly from each other, as well as from their 

 common parent-form, the Gallus bankiva ; and these 

 characters are faithfully transmitted by each breed to 

 their offspring at the corresponding period of life. For 

 instance, the chickens of spangled Hamburghs, whilst 

 covered with down, have a few dark spots on the head 

 and rump, but are not longitudinally striped, as in 

 many other breeds ; in their first true plumage, " they 

 "are beautifully pencilled," that is each feather is 

 transversely marked by numerous dark bars; but in 

 their second plumage the feathers all become spangled 

 or tipped with a dark round spot. 20 Hence in this 

 breed variations have occurred and have been trans- 

 mitted at three distinct periods of life. The Pigeon offers 

 a more remarkable case, because the aboriginal parent- 

 species does not undergo with advancing age any change 

 of plumage, excepting that at maturity the breast 

 becomes more iridescent ; yet there are breeds which 

 do not acquire their characteristic colours until they 



19 'The Variation of Animals and Plants under Domestication,' vol. 

 ii. 1868, p. 75. In the latt chapter but one, the provisional hypothesis 

 of pangenesis, above alluded to, is fully explained. 



20 These facts are given on the high authority of a great breeder, 

 Mr. Teebay, in Tegetmeier's ' Poultry Book,' 1868, p. 158. On the 

 characters of chickens of different breeds, and on the breeds of the 

 pigeon, alluded to in the above paragraph, see ' Variation of Animals,' 

 &c, vol. i. p. 160, 249 ; vol. ii. p. 77. 



