CENTRABCHID^. — XCIl. 233 



ing backwards from the upper angle of the opercle; 

 nearly all -with a black spot at this point, which also 

 covers the flap if the latter is developed; colors usually 

 brilliant, chiefly olive green, with spots or shades of blue, 

 yellow, orange or violet. Fresh water fishes; many of 

 them build nests which they defend with much courage , 

 all are carnivorous, voracious and " gamey." Genera 

 about sixteen; species sixty; all American, and most 

 abundant in the Mississippi Valley, every where forming 

 a characteristic feature of our fish-fauna. The genera 

 are quite well known, and most of them are firmly estab- 

 lished; but the species of some groups, particularly 

 Xeimtis and LepowAs are in a state of almost inex- 

 tricable confusion. 



* Dorsal fin much more developed than anal fin (the base of the 

 former li to 3 times that of the latter), the soft parts of the two 

 fins about equal, of 8 to 14 rays, and ending at the same verti- 

 cal behind, 

 t Body elongate, not greatly compressed ; spines little developed, 

 those of the anal fin, three in number, small and weak ; 

 those of the dorsal, ten, low, the eighth and ninth quite short 

 so that there is a deep notch between the spinous and soft 

 parts of the dorsal, almost breaking the continuity of the 

 fin; caudal emarginate; operculum emarginate behind, 

 ending In two flat points ; mouth very large, the lower jaw 

 longest; palatine teeth well developed; tongue and ptery- 

 goids toothless; gill-rakers long and stout, armed with 

 teeth; supplemental maxillary bone well developed (Mi- 

 (yropt&rinm). Microptbbus, 1. 



f f Body comparatively short and deep, compressed ; anal spines 

 well developed ; dorsal with strong spines, which are con- 

 tinuous with the soft rays, or at least not deeply notched 

 (LepomiTue). 

 a. Tongue and pterygoid bones conspicuously armed with 

 teeth; mouth large, lower jaw longest; maxillary bone 

 broad and flat, with a strong supplemental ossicle behind 



