EIDER DUCK. 



305 



not appear on the breast till the middle of November. 

 This change seemed to go gradually on till June, when 

 the breeding plumage was observed to be about half per- 

 fect. They began to lose their white plumage about the 

 same time as the oldest male, but they did not lose so 

 much of it, as a number of the white feathers remained on 

 the back and breast. They commenced moulting about 

 the same time as the old bird, and the white plumage came 

 on in them much the same as on him. 



No perceptible change takes place in the plumage of the 

 females. 



The windpipe of the male Eider measures nine inches 

 in length, the tube uniform in size throughout ; the bony 

 labyrinth and inferior tubes as represented below. 



VOL. III. 



