180 



ANATID^E. 



The windpipe of the Spur- winged Goose is about sixteen 

 inches long, the tube flattened throughout the greater part 

 of its length, but cylindrical at the bottom. The vignette 

 below represents the lower portion of the windpipe in 

 three points of view. The figure on the right hand shows 

 the tube with its bony enlargement on the left side, being 

 its position in the body of the bird ; the other figures are 

 added to exhibit the various circular and oval apertures 

 which pervade different parts of this bony enlargement, the 

 opposite sides not being exactly alike, either in the number, 

 form, or situation of these apertures in the bone, which in 

 a natural state are closed by delicate transparent mem- 

 brane. The bronchial tubes are divided higher at the 

 back than in front, as seen in the figure on the left, to 

 allow free passage for the oesophagus between them from 

 behind forwards. 



