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ANATID^E. 



fluenced by the action of these muscles altering the relative 

 position of this hollow bulb upon the tube. There is also 

 another peculiarity. On making a longitudinal lateral sec- 

 tion, as shown in the outside figures below, it will be seen 

 that the inner tube of the trachea, at its upper part, has an 

 aperture on each side by which it communicates freely with 

 the cavity within another bony enlargement, situated im- 

 mediately below the superior larynx, and brings to mind 

 the laryngeal cavities found in some of the higher animals. 

 A slip of paper is represented as passing through both 

 apertures. 



