326 VERTEBRATES : FISHES. 



Cyclostomes, or Suckers, 

 chondropterygians with skel- 

 eton very slightly developed, 

 and the body terminated be- 

 fore with a circular or semi- 

 circular lip. Such are the Lampreys. 



SUB-SECTION I. 



THE ORDER OF ACANTHOPTERYGIANS, OR SPINE-FINNED FISHES. 



THIS Order, the most extensive of the Class of Fishes, 

 is at once recognized by the spines which occupy the 

 place of the first rays of the dorsal, or which alone sup- 

 port the first fin of the back whenever there are two 

 dorsals. In some cases, instead of a first dorsal, there are 

 only a few free spines. The first rays of the anal fin are 

 also spines, and there is generally one spine to each ventral. 



PERCID/E, OR PERCH FAMILY. This Family comprises 

 the Perch and its immediate allies, embracing about six 

 hundred species, distributed among fifty or sixty genera. 

 About one fifth of these inhabit fresh water, and the oth- 

 ers are marine. Some are remarkably beautiful. The 

 flesh of all is wholesome, and that of many is highly 

 prized, and much used for food. 



The Genus Perca Perches proper has a dentated 

 preoperculum* bony operculum terminated by two or 

 three sharp points, and a smooth tongue. 



The American Yellow Perch, P. flavescens, Cuv., is 

 from six to twelve inches long, greenish and golden 

 Fig - ^ above, the sides golden yellow, with 



six to eight dark vertical bands, 

 which extend over the back ; the 

 pectorals, ventrals, and anal orange. 

 Yellow Perch, p.jiavesce ns , GUV. This is one of the most common 

 and best known of the fresh-water fishes of the United 

 States. 



