102 THE WOODPECKERS 



along the roof of his mouth. As soon as he 

 wishes to shut his bill, back fly the little bones 

 guided by their hollow sheaths of elastic muscle 



Hyoids of Sapsucker and Golden-fronted Woodpecker. 



into their hiding-place in the top of the bill. 

 The muscular covering is a part of the same soft 

 envelope that we saw lying in wrinkles at the 

 root of the tongue. It covers the whole length 



