FISHES. 



235 



such gifts, they who at most can barely perceive each other in 

 the twilight of the deep, and even if they could see distinctly, 

 what species of pleasure can they derive from such combinations ? 



The teeth of fishes are very numerous, and are attached to 

 almost every one of the bones that enter into the composition of 

 the mouth. They are generally simple spines, curved back- 

 wards ; but innumerable modifications of structure occur. Thus 

 the teeth of the deadly shark are flat and lancet-like, the cutting 

 edges being notched like a saw ; the front teeth of the flounder 

 are compressed plates; some, as the wrasse, have flat grinding 

 teeth, and others, 

 as the genus 

 Chrysophrys, 

 have convex 

 teeth, so nume- 

 rous and so close- 

 ly packed over a 

 broad surface, as 

 to resemble the 

 paving-stones of 

 a street The 

 beautiful Chaeto- 



dons of warm climates have teeth 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 

 L^reat variety. The pike, the perch, the cat-fish, and many others, 

 have their mouth crowded with innumerable teeth ; the carp and 

 the roach have only a fe\v strong teeth in the throat, and a single 

 flat one above, while the sturgeon, the pipe-fish, and the sand- 

 lance are entirely toothless. 



The fins of fishes afford important characters whereby the dif- 

 ferent races are distinguished. Some of them are vertical, con- 

 stituting 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 repre- 



FIG. 244. SKELETON OF HADDOCK. 



