TEETH OF FISHES. 



253 



composed of horny plates or tubercles of different forms, which 

 are disposed with great regularity over the whole surface of the 

 sucker-shaped mouth, so as evidently to secure a deadly hold of 



Dental apparatus of the Lamprey. 

 b fang fixed to the roof. 



any victim seized upon. The tongue (d\ which is very moveable, 

 and capable of being retracted and protruded by means of strong 

 muscles, is likewise armed with serrated teeth, with which, as 

 with a rasp, the lamprey tears through the flesh of its prey. 



In the scari, which have to feed upon the numerous lithophytes 

 that clothe the rocks at 

 the bottom of the ocean, 

 the dental apparatus 

 given to protect their 

 jaws from injury is very 

 remarkable. These fishes 

 have their jaws (a, 6), 

 which resemble the beak 

 of a parrot, covered ex- 

 ternally with a kind of 

 pavement of teeth, an- 

 swering the same pur- 

 pose as the horny invest- 

 ment of the mandibles of 

 the bird, and succeeding 

 each other, from the rear 

 to the front, in such a 

 manner that the bases of the newest form a cutting edge. 

 Thus armed, the parrot-fish browses without difficulty on the 



Beak of Parrotfish. (Scarus nmricatus.) 



