118 THE VITAL FUNCTIONS. 



ease, and in a very short time, by means of this 

 peculiarly shaped bill.* 



Birds which dive for the purpose of catching fish 

 have often a bill of considerable length, which 

 enables them to secure their prey, and change its 

 position till it is adapted for swallowing. 



The Rynchops, or Black Skimmer, has a very 

 singularly formed beak : it is very slender, and the 

 lower mandible very much exceeds in length the 

 upper one ; so that while skimming the waves 

 in its flight, it cuts the water like a plough-share, 

 catching the prey which is on the surface of the 

 sea. 



The Woodpecker is furnished with a singular ap- 

 paratus for enabling it to dart out with great velocity 

 its long and pointed tongue, and transfix the insects 

 on which it principally feeds ; and these motions 

 are performed so quickly that the eye can scarcely 

 follow them. This remarkable mechanism is de- 

 lineated in Fig. 271, which represents the head of 

 the woodpecker, with the skin removed, and the 

 parts dissected. The tongue itself (t) is a slender 

 sharp-pointed horny cylinder, having its extremity 

 (b) beset with barbs, of which the points are di- 

 rected backwards : it is supported on a slender Os 

 Hyoidcs, or lingual bone, to the posterior end of 

 which the extremities of two very long and narrow 

 cartilaginous processes are articulated. | The one 

 on the right side is shown in the figure, nearly in 



* See a paper on the mechanism of the bill of this bird, by Mr. 

 Yarrell, in the Zoological Journal, iv. 459. 



t These cartilages correspond in situation, at the part, at least, 

 where they are joined to the os hyoides, to what are called the cornua, 

 or horns of that bone, in other animals. 



