Body usually oblong, covered with scales, which are typically ctenoid, not smooth nor spinous, and of moderate size. Lateral line typically present and concurrent with the back. Head usually compressed laterally and with the cheeks and opercles scaly. Mouth various, usually terminal and with lateral cleft; the teeth various, but typically pointed, arranged in bands on the jaws, and in several families on the vomer and palatine bones also, as well as on the pharyngeals; gill-rakers usually sharp, stoutish, armed with teeth, but sometimes short or feeble; lower pharyngeals almost always separate, usually armed with cardiform teeth; third upper pharyngeal moderately enlarged, elongate, not articulated to the cranium, the fourth typically present; gills four, a slit behind the fourth; gill membranes free from the isthmus, and usually not connected with each other; pseudobranchiæ typically well developed. Branchiostegals few, usually six or seven. No bony stay connecting the suborbital chain to the preopercle. Opercular bones all well developed, normal in position; the preopercle typically serrate. No cranial spines. Dorsal fin variously developed, but always with some spines in front, these typically stiff and pungent; anal fin typically short, usually with three spines, sometimes with a larger number, rarely with none; caudal fin various, usually lunate; pectoral fins well developed, inserted high; ventral fins always present, thoracic, separate, almost always with one spine and five rays, the _Aphredoderidæ_ having more, a few _Serranidæ_ having fewer. Air-bladder usually present, without air-duct in adult; simple and generally adherent to the walls of the abdomen. Stomach cæcal, with pyloric appendages, the intestines short in most species, long in the herbivorous forms. Vertebral column well developed, none of the vertebræ especially modified, the number 10 + 14 = 24, except in certain extratropical and fresh-water forms, which retain primitive higher numbers. Shoulder-girdle normally developed, the post-temporal bifurcate attached to the skull, but not coossified with it; none of the epipleural bones attached to the center of the vertebræ; coracoids normal, the hypercoracoid always with a median foramen, the basal bones of the pectoral (actinosts or pterygials) normally developed, three or four in number, hour-glass-shaped, longer than broad; premaxillary forming the border of the mouth usually protractile; bones of the mandible distinct. Orbitosphenoid wanting. The most archaic of the perch-like types are apparently some of those of the fresh waters. Among these the process of evolution has been less rapid. In some groups, as the _Percidæ_, the great variability of species is doubtless due to the recent origin, the characters not being well fixed.