ACQUIRED CHARACTERS 317 



and black feathers fell from the Tanagers and were replaced 

 by others of the same colour ; from buff-cream and black the 

 Bob-o-links moulted into buff, cream and black ! There was 

 no exception ; the moult was from nuptial to nuptial, not from 

 nuptial to winter plumage. The dull colours of the winter 

 season had been skipped." Thereby, as he remarks, it is plain 

 that the " sequence of plumage in^ these birds is not in any way 

 predestined through inheritance bringing about an unchangeable 

 succession, in the case of the Tanager, of scarlet and black 

 green and black year after year, but that it may be interrupted 

 by certain external factors in the environmental complex". 



