466 Mr. J. Lewis Bonhote on Moult 



results of the moult are jj^aiued without the bird having to 

 undergo such a severe strain on its system. 



Mr. Chadbourne goes on to state that all individuals of a 

 given species do not acquire their breeding-plumage iu the 

 same way, some acquiring it by moult, others by colour- 

 change, and others again by both processes. This seems to 

 show an intimate connection between moult and change of 

 colour. The Bobolink is not the only bird in which the 

 method of the assumption of the breeding-plumage varies in 

 different individuals. From the head of Larus ridihundus I 

 have taken at the same time new brown feathers and old 

 feathers in process of change, while in other individuals 

 there has been a pure colour-change. The Ruff is an instance 

 of the change going on in two different ways simultaneously. 

 The Ptarmigan, again, is another instance, and from the 

 examples of this species which I have examined I think it 

 doubtful whether it assumes any one of its plumages in a uni- 

 form manner. The fact that a bird will assume its breeding- 

 plumage in some feathers by a change of colour, and in 

 others by a change of feather, leads to the supposition that 

 pigment can find its way up an old and fully-grown feather. 

 It does not seem to me unlikely that, at a certain season, 

 pigment — which is chiefly a waste product, moi'e abundant, 

 on account of the extfa energy expended, at the approach of 

 spring — should be deposited in the follicles of the feathers. 

 If the follicle is at that time engaged in producing a neiv 

 feather, the pigment is placed in it ; if not, it is drawn up 

 into the feather which is already full-grown. The fact of 

 one individual moulting and another not casting a feather 

 offers no real difficulties, as moult is influenced by many 

 different causes, some of which, e. g. heat, food, vigour, 

 &c., are directly dependent on the individual and its 

 surroundings. 



Let us briefly consider the evidence for and against the 

 conveyance of pigment up a feather. Let us take the 

 evidence of our own eyes. 



First, for instance, let us select the case of the Golden 

 V\o\cr [Charadrius pluvialis). If a specimen be examined 



