128 THE \ITAL FUNCTIONS. 



at the points, and either conical or hooked at 

 the extremity, with the points always directed 

 backwards, in order to prevent the escape of the 

 animal which has been seized. Those fishes 

 which subsist on testaceous moUusca have teeth 

 with grinding surfaces, and their jaws are also 

 adapted for mastication. Every part of the 

 mouth, tongue, and even throat, may afford 

 lodgement for teeth in this class of animals. 

 Almost the whole cavity of the mouth of the 

 Anarrhichas lupus, or wolf-fish, may be said 

 to be paved with teeth, a triple row being im- 

 planted on each side ; so that this fish exerts 

 great power in breaking shells. The Shark has 

 numerous rows of sharp teeth, with serrated 

 margins : these at first sight appear to be for- 

 midable instruments ; but as the teeth in the 

 opposite jaws do not meet, it is evident that they 

 are not intended for cutting, like the incisors of 

 mammalia. 



Among Reptiles, we find the Batrachia almost 

 wholly destitute of teeth. Frogs, indeed, exhibit 

 two rows of very fine points ; the one in the 

 upper jaw, and the other passing transversely 

 across the palate : they may be considered as 

 teeth existing in a rudimental state ; for they 

 are not sufiiciently developed to be useful in 

 mastication. There are about forty of these 

 minute teeth on each side in the frog. In the 

 Salamander, there are sixty above and below ; 

 and also thirty on each side of the palate. 



