350 



VERTEBRATES : FISHES. 



PLEURONECTIM;, OR FLOUNDER FAMILY. This Fam- 

 ily comprises fishes which have the body flat, being com- 

 pressed vertically, both eyes on the same side of the head, 

 sides of the mouth unequal, and a dorsal extending the 

 whole length of the back. The side upon which the eyes 

 are placed is always uppermost when the animal is swim- 

 ming, and is deeply colored ; while that on which the eyes 

 are wanting is always whitish. They have no natatory 

 bladder, and seldom quit the bottom. The want of sym- 

 metry between the two sides of the fishes of this family 

 Fig. 226. is seen in no other verte- 



brates. About one hundred 

 and thirty species are known, 

 all of which are marine. 



The Genus Platessa con- 

 tains the Flounders proper, 

 Flounder, B. piana, Mitch. which are from six to twen- 



ty-five inches long. Turbots and Soles are representa- 

 tives of genera closely allied to the preceding one. 



The Genus Hippoglossus embraces the Halibuts, which 

 have the eyes and color on the right side. 



The Halibut, H. vulgaris, Cuv., of the North Atlantic, 

 is from two to eight feet long, ashen-gray on the right 

 side, white on the other. It attains the weight of six 

 hundred pounds in some cases. 



CYCLOPTERID^C, OR LUMP-FISH FAMILY. This Fam- 

 ily comprises fishes whose 

 ventrals are united into a 

 disk or cup-shaped form. 

 By means of the disk, these 

 fishes are able to attach 

 themselves to the surface 

 of the rocks with great 

 Lump-Fish, c. lump, Linn. firmness. The Genus Cy- 



clopterus contains the Lump-Sucker, C. lunipus, Linn., 



Fig. 227. 



