COMMON CRANE. 



505 





iii breadth, of a pale brown colour, blotched and spotted 

 with two shades of darker brown. 



The singular structure of the windpipe and its convolu- 

 tions lodged between the two plates of bone forming the 

 sides of the keel of the sternum in this bird have long been 

 known. The first illustration here given is a representation 

 of the breast-bone of a young male Crane, in which the 

 trachea, or windpipe, quitting the neck of the bird, passes 

 downwards and backwards between the branches of the 

 furcula, or merrythought, towards the inferior edge of the 

 keel, which is hollowed out to receive it ; into this groove, 

 formed by the separation of the sides of the keel, the trachea 

 passes, and is firmly bound therein by cellular membrane, 

 and after making three turns, passes again forwards, then 

 upwards, and ultimately backwards to be attached to the 

 two lobes of the lungs by the bronchial divisions. 



The second representation, in the next opening, is taken 

 from the sternum of an old female Crane, and exhibits the 

 trachea still farther extended, and occupying nearly the 

 whole cavity between the two bony plates forming the 

 keel : a portion of the plate nearest the observer in both 





