.?9pL0GY. 163 



is kept up a constant supply and succession of food to the 

 various animals dependant on them for support. Immense? as 

 the quaniity is, that is consumed for food by Manli-ind, a 

 larger number are used for the purpose of extracting oil, or 

 for maiiure, of some kinds, Man has appropriated every part 

 to some use, as the Cod, whose flesh is eaten, and whose en- 

 trails are either applyed to the same purpose, or formed into a 

 li.ind of g!ue. Of some kinds, only the liver is used to ex- 

 tract the oil, of others, only the skin, as that of the Dog- 

 fish, M'Tiich is used for smoothing the surfaces of hard 

 wood, and various other substances, ansAvering the purpose 

 of fine files. 



Fishes are separated into two divisions, Bony and Carti- 

 laginous, eithei' of which oiders offers an easy gradation 

 from the last order in the class Amphibea, as the general ap- 

 pearance of the Snake, Eel, and Lamprey tribes clearly 

 shew. 



Bony fishes breath through Gills, covered or guarded by 

 bony plates, -.vhich ar-^open on one side, and are dilatable at 

 pleasure, by means of a row of bones situated on the under 

 part ; this division contains four orders, the characters of 

 which are taken from the absence, or situation of the 

 Ventral fins. 



Cartilaginous fishes have their muscles supportie^ by car- 

 tilages, instead of bones, and they breathe through apertures 

 or holes, situated generally on the sides of the neck ^ they 

 consist of only one order. 



M 2 



