78 INTRODUCTION. 



sharks will exhibit an example of the first, of the 

 roost formidable kind, of great size and strength, 

 smooth and piercing, or sharp, but serrated. 

 Those of the rays or skates of the second, fitted 

 for bruising, where the food is in a great part shell 

 fish, and where the teeth are arranged as a dense 

 pavement. In others, again, the teeth, various in 

 size and strength, are placed in the jaws, vomer, 

 tongue, arches of the branchiae, and in the throat. 

 The latter arrangement is one of the most singular, 

 and bears the title among French ichthyologists 

 of " Dents en velour," from their exhibiting the 

 appearance, to the naked eye, of the pile of coarse 

 velvet. These act by the compression of the 

 lower pharyngeal muscles, and an example will 

 be found in the genus Cyprinus, to which belong 

 the greater part of those fishes which, by English 

 anglers, are denominated " Leather Mouths/' The 

 food being seized, is almost immediately swallow- 

 ed ; and, such is its voracity, that substances 

 entirely foreign are often taken in, as may almost 

 always be seen on examining the stomach of a cod, 

 which sometimes presents a most heterogeneous 

 mass, little fitted for nutrition. 



Although the teeth and jaws, with pursuit, are 

 the principal accessaries for securing prey, various 

 fishes, deprived of swiftness, entice their prey by 

 stratagem. Such are all the Siluri, with long fila- 

 mentous appendages to the lips, which, in some, are 



