302 THE DESCENT OF MAN 



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

 their common parent-form, the Oallus bankiva ; and these 

 characters are faithfully transmitted by each breed to their 

 offspring at the corresponding periods of life. For instance, 

 the chickens of spangled Hamburgs, while 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 plumage "they are beautifully pencilled," 

 that is, each feather is transversely marked by numerous 

 dark bars; but in their second plumage the feathers all be- 

 come spangled or tipped with a dark, round spot." Hence 

 in this breed variations have occurred at, and been trans- 

 mitted 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 colors until they have moulted two, three, or 

 four times ; and these modifications of plumage are regularly 

 transmitted. 



Inheritance at Corresponding Seasons of the Year. — 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 colors and other decorations 

 during the breeding-season alone. Pallas states, °' that in 

 Siberia domestic cattle and horses become lighter- colored 

 during the winter; and I have myself observed and heard 



^ These facts are given on the high authority of a great breeder, Mr. 

 Teeliay; see Tegetmeier's "Poultry Book," 1868, p. 158. On the characters 

 of chickens of difEerent breeds, and on the breeds of the pigeon, alluded to in 

 the following paragraph, see "Variation of Animals," etc., vol. i. pp. 160, 249; 

 vol. ii. p. 17. - 



^* "Novae species Quadrupedum e G-lirium .ordine," 1718, p. 7. On the 

 transmission of color by the horse, see "Variation of Animals, etc., under 

 Domestication," vol. i. p. 51. Also vol. ii. p. 71, for a general discussion on 

 "Inheritance as limited by Sei." 



