376 



ANATID^l. 



white patch at the base of the upper mandible, by the end 

 of January, but it more frequently begins at a later period, 

 namely, in March. 



The trachea of this species is singular in its form, differ- 

 ing from the character of those of the Ducks in general, 

 and bearing some resemblance to those of the Mergansers, 

 both in the tube and in the labyrinth. The length is about 

 nine inches, the diameter of the upper half of the tube 

 equal in size and small ; at the commencement of the 

 second half, the tube is dilated to four times the previous 

 size, and the rings are so arranged as to lay flat upon each 

 other. The last, or fourth, portion again contracts till it 

 ends in the labyrinth, of which the vignette below repre- 

 sents the surface nearest the back of the bird. The 

 bronchial tubes are observed to be unequal in length, to 

 compensate for the obliquity of the inferior surface of the 

 labyrinth, which, as usual, is made up partly of bone and 

 partly of membrane. The voice is said to be very loud, 

 and hence this Duck was called clangula. 



