256 



FISHES OF ILLINOIS 



to 30 orange spots, somewhat smaller in size than the pupil, irregu- 

 larly distributed, their color deeper and brighter in males than in 

 females, the spots usually a dull brown in the latter; top of head 

 slaty; a suggestion of wavy lines of emerald on cheeks; black color on 



the opercular flap mostly confined to the mem- 

 branous portion, barely tipping the operculum; the 

 pale margin of the membrane quite wide, its color 

 variable — pale lavender, pinkish, or light crimson; 

 spinous dorsal with narrow edging of crimson and 

 soft portion with wide margin of orange in males; 

 ventrals and anal orange, color deeper and approach- 

 ing crimson in males; distal margin of anal dusky; 

 other fins plain. Head 2.3 to 2.9 in length, its top 

 long, flattened or verv^ little convex; eye 3.7 to 4.5 

 in head; mouth moderate, maxillary extending past 

 front of orbit, never to its middle, 2 . 7 to 3 in head; 

 jaws about equal; lower pharyngeals narrow, very 

 weak, the teeth slender and very acutely pointed; 

 opercular bone sharply rounded backward, black only 

 at its tip; the membranous flap long and broad and 

 very thin, not forming a pale edging only, but bear- 

 Opercular flaps of Lf- ^^S the most of the black color of the opercular 

 pomis hitmilis, one Spot; gill-rakers long, rather more than J diameter 

 figure entire, the of eye. Dorsal X, 10 or 11; spinous and soft por- 

 other showing flap ^jq^s of about equal height; the spines slender, rather 

 - long, the longest 2.4 to 2 . 6 in head in adults, usually 



about 2.5; anal III, 9; pectorals 1 to 1.3 in head, 

 usually about 1.1; ventrals reaching to base of first 

 anal spine. Scales 4 or 5, 34-42, 11 to 13; pores 

 lacking on some scales; rows on cheek 5 or 6. 



Fig. 63 



mis and fleshy or 

 membranous bor- 

 der. 



This is a showy and, indeed, a brilliant little fish, of a size so 

 small that it is ornamental only. Our 177 collections were taken 

 most frequently from creeks (2.06), next from the smaller rivers 

 (1.51), and then from Rowland lakes (1.19), none at all coming 

 from upland glacial lakes. They were well distributed through the 

 state, most abundantly, however, in the prairie region of central 

 Illinois, where this species is found in frequent company wqth the 

 green sunfish. It is often taken along the shore of the Illinois River 

 and in adjacent lakes and sloughs, but has been rare or absent in 

 extreme northern Illinois, occurring in the Fox and Rock river sys- 

 tems only near the mouths of those streams. Its general distribu- 

 tion in the smaller rivers, and in lakes and ponds of the bottom-lands, 

 brings it also into contact with the crappies. Its associative coeffi- 

 cient is 2.35 for the green sunfish and 2 . 94 for the pale crappie. If 

 one may judge from its feeding structures, it is protected from 

 serious competition with these companion species by differences in 

 its food. 



