Ghap. VIII. 



Sexual Selection. 



22Q 



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 down-covered chickens, the young birds in their first true 

 plumage, and the adults differ greatly from one another, as well 

 as from their common parent-form, the G alius hankioa ; and 

 these characters are faithfully transmitted by each breed to their 

 offspring at the corresponding periods of life. For instance, the 

 chickens of spangled Hamburg's, whilst covered with down, have 

 a few dark spots on the head and rump, but are not striped 

 longitudinally, as in many other breeds ; in their first true plu- 

 mage, " 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. 34 Hence in this breed variations have occurred at, 

 and been transmitted to, three distinct periods of life. The 

 Pigeon offers a more remarkable case, because the aboriginal 

 parent species does not undergo any change of plumage with 

 advancing age, excepting that at maturity the breast becomes 

 more iridescent ; yet there are breeds which do not acquire their 

 characteristic colours until they have moulted two, three, or 

 four times ; and these modifications of plumage are regularly 

 transmitted. 



Inheritance at corresponding Seasons of the Fear. — With animals 

 in a state of nature, innumerable instances occur of characters 

 appearing periodically at different seasons. We see this in the 

 horns of the stag, and in the fur of arctic animals which becomes 

 thick and white during the winter. Many birds acquire bright 

 colours and other decorations during the breeding-season alone. 

 Pallas states, 35 that in Siberia domestic cattle and horses become 

 lighter-coloured during the winter ; and I have myself observed, 

 and heard of similar strongly marked changes of colour, that is, 

 from brownish cream -colour or reddish-brown to a perfect white., 

 in several ponies in England. Although I do not know that this 

 tendency to change the colour of the coat during different seasons 



chapter but one, the provisional 

 hypothesis of pangenesis, above 

 alluded to, is fully explained. 



34 These facts are given on the 

 high authority of a great breeder, 

 Mr. Teebay ; see Tegetmeier's ' Poul- 

 try Book,' 1868, p. 158. On the 

 characters of chickens of different 

 breeds, and on the breeds of the 

 pigeon, alluded to in the following 

 paragraph, see ' Variation of Ani- 



mals,' &c, vol. '.. pp. 160, 249; 

 vol. ii. p. 77. 



35 i Nova: species Quadrupedum « 

 Glirium ordine,' 1778, p. 7. On 

 the transmission of colour by the 

 horse, see ' Variation of Animals, 

 &c, under Domestication,' vol. i. p. 

 51. Also vol. ii. p. 71, for a gene- 

 ral discussion on ' Inheritancs a/ 

 limited by Sex.' 



