112 



ANATID.E. 



These are the peculiarities of structure which belong to the 

 tube and the sternum. The bronchia? are very short ; but 

 the flexible part intervening between the bone of divarication 

 and the bronchial rings is considerable, producing an effect to 

 be hereafter noticed. This elongated, flexible, and delicate 

 portion being defended on each outer side by a distinct mem- 

 brane, attached to the whole edge of the bone of divarication, 

 and to a slender semicircular bone on each side, by which it 

 is supported. 



The muscles of voice with which this bird is provided, pass 

 down, as usual, one on each side of the trachea, till the tube 

 is about to enter the cavity in the keel, they then quit that 

 part of the tube to be attached to the ascending portion of 

 the curve, which they follow, ultimately dividing into two 

 slips, one of which inserted upon the surface of the bone of 

 divarication governs the length of the preceding flexible por- 

 tion of the tube ; the other slip passes off downwards to be 



