THE NATURALIST. 



FEBRUARY, 1832. 



ORNITHOLOGY. 



NO. II. 



Trachea of Birds. The trachea, or aspira arteria, as 

 the windpipe is scientifically called, is in some species of 

 aquatic birds of a most singular structure, possessing an 

 enlargement at the bottom, which has been termed a laby- 

 rinth. This labyrinthic part is of essential use to the orni- 

 thologist, in discriminating the species, as well before their 

 arrival at maturity, as in the several changes of plumage 

 incidental to season. With a view to promote a discovery 

 so essential, we propose to fix names to the several parts in 

 order to facilitate description. 



In the labyrinthic part of the windpipe [trachea) there is a 

 material difference in conformation, which forms two natural 

 divisions, and, as might be expected, belong to birds of dif- 

 ferent habits ; one is a structure found among the diving 

 ducks with short wings, and some other birds that collect 

 their food mostly under water ; and as far as experience has 

 gone, this line of separation appears constant. There are, 

 indeed, one or two species which deviate somewhat from 

 either division, but do not connect the two. 



In order to explain this subject, we shall consider that the 

 windpipe of such birds consists of three principal parts — that 

 is to say, the windpipe, properly so called ; the labyrinth, or 

 swelling at the lower extremity ; and the divarications at the 

 bottom, {bronchi(B,) which connect the windpipe with the 

 lungs. The principal distinction in the labyrinth of the two 

 divisions is as follows : — 

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