396 FISHES. 



scarcely exceed a length of twelve inches, and are very uni- 

 formly coloured, red, pink, and silvery prevailing. 



The following three genera form a group by themselves, which, 

 however, is defined rather by its geographical limits and 

 similarity of general appearance than by distinctive anatomical 

 characters. The species are abundant in the fresh waters 

 of the United States, and well known by the name of " Sun 

 Fishes." They rarely exceed a length of six inches, and are 

 not used as food. The number of species is uncertaiu. 



Centraechus. — Body short, compressed, with scales of mode- 

 rate size. All the teeth villiform, without canines ; teeth on 

 the vomer, palatines, and on the tongue. One dorsal fin ; anal 

 generally with more than three spines. Praeoperculum without 

 serrature ; operculum not lobed. 



Bryttus.' — Body short, compressed, with scales of moderate 

 size. All the teeth villiform, without canines ; teeth on the 

 vomer and palatine bones. One dorsal fin with nine or ten, 

 anal with three spines. Prseoperculum not serrated ; operculum 

 with a rounded membranaceous coloured lobe behind. 



PoMOTlS. — Body short, compressed, with scales of moderate 

 length. All the teeth villiform, without canines ; teeth on the 

 vomer, but none on the palatine bones. One dorsal, with from 

 nine to eleven spines, anal with three. Prseoperculum entire or 

 minutely serrated ; operculum with a rounded membranaceous 

 coloured lobe behind. 



A North American Freshwater genus, Aphredoderus, occu- 

 pies a perfectly isolated position in the system, and is evidently 

 the type of a distinct family. It resembles the " Sun-fishes " 

 of the same country with regard to the structure of the verti- 

 cal fins, but has the vent situated in front of the ventrals, 

 which are composed of more than five soft rays. The body is 

 oblong, compressed, covered with ctenoid scales. The dorsal 

 fin is single, and has three spines in front. Infraorbital and 

 prseoperculum with spinous teeth. Villiform teeth in the 



