BUFF-BREASTED GOOSANDER. 215 



circumstances : — The female of Merganser Castor is consider- 

 ably larger, with the bill thicker in proportion to its length, 

 and especially at the base. The crest-feathers of the former 

 are not, as in the latter, shorter in the middle, and longer at 

 the fore and hind parts. The grey of the back is uniform, 

 and the white wing-spot entire, in Merganser Castor, while in 

 Merganser Serrator the back is brownish-grey, and the white 

 wing-spot crossed by a black band. 



