GREEN WOODPECKER. 



467 



so much feeds, while it is freely supplied with mucus each 

 time that it is retracted into the mouth. An examination of 

 the crop shews that the prey is not transfixed, as many 

 people have supposed, by the horny tip of the tongue, but 

 simply captured by the application of its slimy and adhesive 

 surface, though probably the barbs assist in detaching the 

 insects from their hold. 



Another anatomical peculiarity which has been supposed 

 to be obviously adapted to the habits of the bird is the shal- 

 lowness of the keel of the breastbone : but when the skeleton 



of this Woodpecker (as figured above) is compared with that 

 of many other Picarian birds, the same character will be 

 found in some of them which are not known to climb like 

 the Picidce, and in certain members of the latter, not always 

 those which have the greatest power of flight, the keel seems 

 to be proportionally deeper than it is in the present species, 

 though they are believed to climb as well as it does. Thus, 



