6 FRESH-WATER FISH. 



covered with scales. A great part of the tongue is 

 bony, and as it is often furnished with teeth, and other 

 hard parts, the sense of taste cannot be very acute. 

 The teeth of fish vary greatly in their position. 

 They are found, as I have said, on the tongue; 

 they are also found on the intermaxillaries, the 

 maxillaries, the lower jaw, the vomer, the palate, 

 the gill-arches, and even on the bones of the pharynx, 

 behind these. Some fish, on the other hand, are 

 almost, if not altogether, toothless. The work of re- 

 spiration is carried on by the branchiae, or gills, which 

 consist of arches of bone attached to the os hyoides, or 

 bone of the tongue. The water taken in by the mouth 

 passes among the filaments of the gills, and escapes by 

 the gill openings towards the rear. It is probable that 

 this jet of water, thrown backwards from the gill- 

 openings, may assist the progressive motion of the fish, 

 which is chiefly effected by the lateral motion of the 

 tail, which strikes right and left against the water. 



The soft-finned fishes (MALACOPTERYGII) are classed 

 according to the position of the ventral fins. If these 

 are on the belly, the fishes are abdominal, if attached 

 to the shoulder, they are sub-brachian, and if wanting, 

 they are apodal. The Cyprinidce, or CARP family, stand 

 the first, and include, besides the true carp, the barbel, 

 the gudgeon, the tench, the bream, the roach, the dace, 

 the chub, the bleak, and the minnow. This family 

 of fish have the mouth shallow, the jaws feeble, very 

 often without teeth, and the margin formed by the 

 outer maxillaries ; but they have the pharynx strongly 

 toothed. They have few gill rays; the body is scaly; 

 and they have no adipose dorsal. They are the least 

 carnivorous of all fishes. The second family are the 



