SMEW. 



281 



of the smaller wing-coverts is mixed with ash-grey, and the 

 under surface of the body is of a dull white. Females pro- 

 bably assume the black patch on the lore, and the more pure 

 white colour on the wing-coverts at their second autumn 

 moult. 



The trachea of the male Smew is about nine inches in 

 length, the tube very narrow at the upper part, but increases 

 gradually till it attains the diameter shown in the figure on 

 the left side of the vignette below ; the bony rings being 

 firmly ossified throughout. The labyrinth, it will be ob- 

 served, is at right angles with the line of the tube, the spaces 

 in the bone supplied with tympanic membranes ; the bron- 

 chial tubes short. The figure on the right is from the lower 

 portion of the windpipe of the female, which preserves the 

 same simple character as those of the Ducks. Both are here 

 represented of the natural size. 



