OF PISHES. . 45 



enamelled, with which the hardest covering of 

 such marine animals as they are able to get within 

 their grip, are readily crushed. 



We have various specimens in our cabinet, of 

 this crushing apparatus, which are as difficult to 

 describe as they would be to represent in draw- 

 ings. The entire roof of the mouth, in some of 

 the heads which came from South America, is as 

 hard as the enamel of a molar tooth, yet so 

 rough, as to hold the morsel from sliding, till 

 ground into a proper condition by the opposing 

 jaw, which has no tongue connected with it. 



EXTERNAL COVERINGS. 



The scales, which constitute the coverings of most 

 of the edible fish, it has been, thought, first suggest- 

 ed the idea of tihng or shingling edifices. Scales, 

 in the Levitical law, w^ere the evidences of a clean, 

 or in other words, of an edible fish. The direct 

 influence of that conserv^atory regulation, in rela- 

 tion to this kind of food, is observable in the mar- 

 kets of all christian countries. Such as have 

 smooth skins, exude an oily secretion, that facili- 

 tates their movements, almost without friction. 

 The first class inhabit the neighborhood of rocky 

 shores, and require a coat of mail to prevent lacer- 

 ations of their bodies ; the second, burrow in filth, 

 and steal unexpectedly upon their unsuspecting 

 prey. 



