304 ANATID^E. 



plumage as to sex. About a month after their arrival the 

 male birds began to get much darker in colour, almost 

 black, and by the middle of October a few white feathers 

 began to appear on the back. The white feathers did 

 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 

 is now coming on 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. 



