128 THE VITAL 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. 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 implanted 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 ap- 

 pear to be formidable 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 whatever may be their 

 uses, 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 be- 

 low ; and also thirty on each side of the palate. 



