316 FISHES. 



The beautiful CliEetodons of warm climates have 

 teetli which resemble bristles, and these are set close 

 together like the hairs of a brush ; while the Perch 

 of our own rivers has them still more slender, minute, 

 and numerous, so as to resemble the pile of velvet. 

 Another of our well-known fishes, the bold and fierce 

 Pike, is armed with teeth scarcely less formidable 

 in size, form, and sharpness than the canines of a 

 carnivorous quadruped. In number, also, there is 

 great variety. The Pike, the Perch, the Cat-fish, 

 and many others, have their mouth crowded with 

 innumerable teeth; the Carp and the Eoacli have 

 only a few strong teeth in the throat, and a single 

 flat one above, while the Sturgeon, the Pipefish, and 

 the Sand-lance are entirely toothless. 



The fins of fishes afford important characters 

 whereby the different races are distinguished. Some 

 of them are vertical, constituting a kind of keel and 

 rudder. Those on the back are named dorsals, those 

 behind the vent, and under the tail, anals, and at 

 the extremity of the tail caudal fins. These differ 

 in their number, size, and the nature of the rays 

 that support them : sometimes they are spinous, and 

 sometimes soft and jointed. The remainder of the fins 

 are double, or form pairs, and represent the limbs of 

 other classes of vertebrate animals. Those corre- 

 sponding to the arms or wings are called pectorals, and 

 are invariably fixed behind the gills ; but those which 

 represent the feet, named ventrals, may be placed 

 either forwards, beneath the throat, or more or less 

 backwards, as far as the commencement of the tail : 

 both may differ in size, in the quality of the fin-rays, 

 in their number and structure, or one or both pairs 

 may be wanting. Eels, for example, have no ventrals. 

 Muraenae have neither ventrals nor pectorals, and there 

 are fishes that have no fins at all. 



The food of fishes consists principally of animal 

 matter. Those that inhabit fresh waters live upon 

 worms, mollusks, the larvae of water-insects, or such 

 flies as play or alight upon the surface ; others feed 



