SEXUAL SELECTION. 259 



tendency is well-established. A new character, appearing 

 in a young animal, whether it lasts throughout life or is 

 only transient, will, in general, reappear in the offspring at 

 the same age and last for the same time. If, on the other 

 hand, a new character appears at maturity, or even during 

 old age, it tends 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 dwelt on this sub- 

 ject sufficiently in another work,* 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 

 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 Gallus 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 penciled," that is, each feather is transversety 

 marked by numerous dark bars; but in their second plum- 

 age the feathers all become spangled or tipped with a dark 

 round spot, f 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 abo- 

 riginal parent-species does not undergo any change of plum- 

 age with advancing age, excepting 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 



* " The Variation of Animals and Plants under Domestication," 

 vol. ii, 1868, p. 75. In the last chapter but one the provisional hypo- 

 thesis of pangenesis, above alluded to, is fully explained. 



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

 Mr. Teebay; see 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 following paragraph, see " Variation of 

 Animals," etc., vol. i, pp. 160, 249; vol. ii, p. 77. 



