MANUAL OF NATURAL HISTORY. 103 



large, high ; profile abrupt, sub-vertical ; eyes 

 lateral, close to crown ; mouth and teeth very 

 small ; ventral profile of fish nearly straight ; 

 opercula denticulated ; covered along the 

 body with large deciduous scales ; dorsals 

 two, remote ; caudal fin forked ; two fleshy 

 cirrhi beneath lower jaw. 



42. FAMILY. Naked-headed Perches (Helotidae). 



Head and muzzle naked ; dorsal fin one, 

 deeply emarginate ; dorsal, and often anal 

 fins sheathed at base with scales ; pectorals 

 pointed ; spines on middle of operculum ; 

 jaw-teeth numerous, small, close-set. 



43. FAMILY. Spiny-headed Perches (Holocentridse). 



Body covered with hard, rough, or denticu- 

 lated scales, or mailed plates ; head very 

 spiny ; mouth often oblique ; dorsal emar- 

 ginate. 



44> FAMILY. Serpentiform- Perches (Percophidse). 

 Body ovate, or lengthened; ventrals before 

 pectorals ; dorsals entire, mostly single ; spi- 

 nal rays weaker, and shorter than the others. 



45. FAMILY. Sea-Perches (Serranidse). Body ob- 



long ; dorsal fin single, emarginate ; branchial 

 membrane mostly with seven rays ; jaws 

 with strong canines. 



46. FAMILY. Perches (Percidse). Body oblong; 



scales distinct, generally hard or rough ; teeth 

 in jaws, on vomer and palate ; operculum 

 spined ; pre-operculum serrated ; dorsal fins 

 two, distinct ; no canines. 



