98 THE VITAL FX^NCTIOXS. 



the solid portions arc rclalncd in the inoiitli. Tlic duck af- 

 fords an instance of tliis structure; wliich is, however, still 

 more stron«j;ly marked in the genus Mergiis^ or Merganser, 

 where tiie whole Icngtli of tlie inarL!;in of the hill is beset 

 with small sliarp pointed teeth, directed backwards: thc}^ are 

 jiarticularlv conspicuous in the Merf^its sej'ratnr, or red- 

 l)rcastc(l Mcri^nnsor. 'J'he oI)ject of the ])arbs and fringed 

 processes which arc apj^ended to the tongue in many birds, 

 such as that of the Tuvcan and the Pan^akcet^ appears in 

 like manner, to be the detention of substances introduced 

 into the mouth. 



The beak of the Hxmatopus, or Oyster-catcher, has a 

 wedge shape, and acts like an oyster-knife for opening bi- 

 valve shells. 



In the Loxia curvirosira, or Cross-])ill, the upper and 

 lower mandibles cross each other when the mouth is closed, 

 a structure which enables this bird to tear open the cones of 

 the pine and fir, and pick out tlie seeds, by insinuating the 

 bill between the scales. It can split cherry stones with the 

 utmost ease, and in a very short lime, by means of this pe- 

 culiarly shajK'd 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 changes its position till it is adapted 

 for swallowinc;. 



The li/iijnchnps, or black Skimmer, has a very singular- 

 ly formed beak; it is very slender, but 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 

 plotigh-share, catching the prey which is on the surface of 

 the sea. • 



The Woodpecker is furnished with a singular apparatus 

 for enabling it to dart out with great velocity its long and 

 jminted tongue, and transfix the insects on which it princi- 

 pally feeds; and these motions arc performed so quickly 



• Ser .1 papor on the nicclianism of the bill of this bird, by Mr. Yan-cll, 

 in the Zoolojric.il .lonmal, iv. 4.'>9. 



