PERCID2E — THE PERCHES 269 



males, and are usually placed among fallen leaves or fibrous 

 rootlets, or, perhaps, on plain sand or gravel. The sand, gravel, 

 or leaves are scooped out of the center to form a ridge about the 

 nest a few inches high. The male seeks the female or guards 

 the nest till she appears. The spawning is intermittent, and 

 the process of sexual excitation of the female by the male is 

 similar to that observed in the small-mouthed bass. The 

 spawning season is from May to June. The eggs are viscid, 

 and hatch in eight to ten days. The young are said to remain 

 together in more compact schools than the small-mouthed 

 species, making it easy to seine the fry (Lydell). They reach a 

 length of about 6 inches in the first year after hatching. 



This fish always brings a good price in the market, though 

 it is not specially sought. While far superior to the coarse 

 river fishes, it is excelled in flavor and other edible qualities by 

 trout and whitefish. 



It bears transportation and acclimatization admirably, and 

 has been introduced successfully into the waters of the Pacific 

 states and of more than one country of Europe. It is propagated 

 by the methods of pond culture, but does not submit to stripping 

 and the ordinary methods of artificial culture used for Salmonidce 

 and other species. 



The black-bass fisheries of Illinois, practically consisting 

 altogether of the present species, amounted in 1894 to nearly 

 90,000 lb— 69,000 lb of these coming from the Illinois River 

 alone — and in 1899 to more than 120,000 lb, of which the Illinois 

 River produced 102,000. 



Family PERCID^l 



THE PERCHES 



Body more or less elongate, terete or compressed; dorsal and ventral 

 outlines more or less unlike; scales rather small, always ctenoid, adherent; 

 head scaly, or not; lateral line usually present, not extending on the caudal 

 fin ; skeleton osseous ; vertebras 30 to 48, the anterior ones without transverse 

 processes; ventral fins thoracic, 1, 5; 2 dorsal fins, the first of 6 to 15 spines; anal 

 spines 1 or 2, the usual number 2; caudal fin lunate, truncate, or rounded; no 

 mesococracoid; gill-membranes separate or connected, not joined to isthums; 

 branchiostegals 6 or 7; pseudobranchise small, glandular and concealed, or 

 wanting; gill-rakers slender, toothed; preopercle entire or serrate; opercle 

 usually ending in a single flat spine; mouth various, terminal or inferior, large 

 or small; premaxillary protractile, or not; supplemental maxillary not distinct; 

 jaws, vomer, and palatines with bands of teeth, which are usually villiform, 

 but sometimes mixed with canines; vomer or palatines occasionally without 



