470 Mr. J. lA-wif- Bonlioto on Moult 



some do moult their l)0(ly-feathcrs in sprinj;-, 1 am iniually 

 certain, from those I have had under observation, that 

 they do not all do so. The only attempt to account for 

 feathers being found in all stages of colour between the two 

 extremes (for Dr. Allen evidently acknowledges that such 

 feathers are found) is in the following paragraph : — 



"If one will take a g«jod series of specimens in jnoult 

 (unfortunately specimens are rare) in the case of species 

 A\hich are alleged to, and which have the appearance of 

 changing colour without moulting, it will be found that the 

 parti-coloured and apparently changing feathers have this 

 appearance wlien tiiey first break from the sheath in which 

 they are formed, and that these deceptive feathers have not 

 necessarily acquired their peculiar appearance by a subse- 

 quent and quite inconceivable change in the amount, arrange- 

 ment, and character of the colouring matter." 



This form of change, however, which is, I grant, found in 

 one or two species of birds, and of which the Corncrake 

 offers an analogous but not quite similar example, is in 

 reality a pure colour-change, although it is apparently so 

 hurried on as to occur concurrentl}' with the moult. The 

 best example is that of the Great Northern Diver, in which 

 the feathers, when first assumed, are of a bhiish grey, and 

 in which the bird begins to assume tiie breeding-dress 

 before these are fully formed. That is the normal form of 

 moult ; but it frequently happens, especially among younger 

 birds, that this colour-change is deferred till a month or 

 more after the feathers are fully grown, but then takes 

 place exactly as when the follicle of the feather was in active 

 communication with the body ; therefore it is obviously not 

 necessary for the change that the feathers should still have 

 living connection with the body. 



The other paper, by Mr. Stone, is one well worth reading 

 by those interested in moult and colour-change ; but although 

 Mr. Stone's paper is complete to a certain point, his studies 

 have been chiefly, if not entirely, confined to the smaller 

 birds of the North-American continent^ and to those Orders 

 in which the colour-change is most conspicuous, such as the 



