PERCID.-E THE PERCHES 269 



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 white- 

 fish. 



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 Salmonidcs 

 anil other species. 



The black-bass fisheries of Illinois, practically consisting alto- 

 gether 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 PERCIDjE 

 (the perches) 



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

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

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

 caudal fin; skeleton osseous; vertebrae 30 to 48, the anterior ones with- 

 out transverse processes; ventral fins thoracic, I, 5 ; 2 dorsal fins, the first 

 of 6 to IS spines; anal spines 1 or 2, the usual number 2 ; caudal fin lunate, 

 truncate, or rounded; no mesocoracoid ; "ill-membranes separate or con- 

 nected, not joined to isthmus; branchiostegals 6 or 7 ; pseudobranchias 

 small, glandular and concealed, or wanting; gill-rakers slender, toothed 

 preopen le entire or serrate; opercle usually ending in a single flat spine; 

 mouth various, terminal or inferior, large or small; premaxillary pro- 

 tractile, or not; supplemental maxillary not distinct; jaws, vomer, and 

 palatines with bands of teeth, which are usually villiform, but some- 

 times mixed with canines; vomer or palatines occasionally without 



