TEETH OF FISHES. 43 



those crawling species before alluded to, which volun- 

 tarily quit the water in search of new habitations. 



(45.) The teeth of fishes, as before remarked, are 

 varied in the most surprising manner in regard to their 

 situation, but less so in their construction ; and these 

 instruments are far more numerous in this than in any 

 other class of animals. They are not confined, like those 

 of quadrupeds and reptiles, to the two jaws, but are often 

 disposed in all parts of the mouth. The maxillary 

 teeth are those which are most external, and are placed 

 on the jaws, properly so called, in quadrupeds; and they 

 correspond to the cutting edges of the two mandibles 

 in birds. Parallel to the upper jaws, internally, are 

 the palatine bones, which often support other teeth : 

 between these bones, and in the centre of the palate, is 

 the vomer, — a name given to that bone which forms the 

 roof of the mouth; and this also is frequently armed 

 with teeth, even when the jaws and lateral palatine 

 bones are completely smooth, as in the instance of the 

 common carp, tench, &c. : the tongue, also, is sometimes 

 armed with other teeth, as in the pike, &c. : sometimes 

 all these are so thick and numerous, that they seem like 

 a dense forest of teeth, capable of crushing the most 

 minute substance. To describe the different forms of 

 these teeth would be almost impossible : they are in ge- 

 neral more or less pointed ; in the herbivorous fishes 

 they are formed for the purpose of pressing; and in 

 such as feed upon testaceous animals, they are so much 

 rounded as to be analogous to the molar teeth of quad- 

 rupeds. In the SiluridcB, and other genera, they are so 

 delicate and flexible as to resemble the pile of velvet : 

 hence we may term such teeth setaceous. In the sharks 

 they are compressed, and serrated on their sides; while 

 in the Rays they are round, and placed in the manner of 

 paving stones or mosaic : such teeth are therefore termed 

 tessellated. In many of the genera (as Laarida) they 

 are moveable at their base in an inward direction, to 

 admit a free passage to what is swallowed. Among the 

 cheloniform fishes, the absence of true teeth is supplied, 



