216 FISHES. 



Most of them prefer clear running water, where they 

 lie on the bottom concealed under stones, darting when 

 frightened or hungry with great velocity for a short 

 distance by a powerful movement of the fan -shaped 

 pectorals, then stopping as suddenly. They rarely use 

 the caudal fin in swimming, and they are never seen 

 moving or floating freely in the water like most fishes. 

 When at rest they support themselves on their extended 

 ventrals and anal. Pleurolepis, unlike the others, pre 

 fers a sandy bottom, where, by an almost instantaneous 

 plunge, it buries itself in the sand and remains quiescent 

 for hours at a time, with only its eyes and snout visible. 

 All are carnivorous, and, in their way, voracious. All 

 are of small size, the largest (Percind) reaches a length 

 of about eight inches, while the smallest (Microperca), 

 which is the smallest spiny -rayed fish known, barely 

 attains a length of an inch and a half. 

 * Lateral line incomplete or wanting ; body normally more or 

 less compressed; jaws nearly even, lower jaw sometimes 



projecting. (POSCILICHTHYIN^E.) 



f No lateral line ; dorsal spines 6 or 7 ; fins barred. 



MlCROPERCA, 1. 



ff Lateral line present on anterior part of body. 

 a. Dorsal fins slightly connected at base. 

 b. Spinous dorsal very low, scarcely more than half as 

 high as soft part, commonly of 8 spines; spines in 

 adult (male) ending in little fleshy knobs, in others 

 pointed ; color plain or with black bars and lines of 

 dots; a black shoulder spot; fins with black lines, 

 but no red or blue shades. . . CATONOTUS, 2. 

 bb. Spinous dorsal not low, nearly as high as the soft part; 

 dorsal spines 10 to 12; colors brilliant; fins (in males 

 at least) with bright shades of red and blue, 

 c. Throat and breast deep blue; dark dots along the rows 

 of scales; a dark shoulder spot; sides often with 

 red dots, but not notably barred. NOTHONOTUS, 3. 



