256 



FISHES OF ILLINOIS 



olive, the sides sprinkled with fine dots of gold to emerald; belly deep orange, 

 dusted with brown; sides with about 20 to 30 orange spots, somewhat smaller 

 in size than the pupil, irregularly 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 con- 

 fined to the membranous portion, barely tipping the 

 operculum; the pale margin of the membrane quite wide, 

 its color variable pale lavender, pinkish, or light crim- 

 son; spinous dorsal with narrow edging of crimson and 

 soft portion with wide margin of orange in males; ven- 

 trals and anal orange, color deeper and approaching 

 crimson in males; distal margin of anal dusky; other 

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

 or very 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 edg- 



Opercular flaps of Le- ing Only > but bearin g the most of the black color f the 



pomis humilis, one opercular spot; gill-rakers long, rather more than ^ 

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

 ther showing flap portions of about equal height; the spines slender, rather 

 ep y e r ; long, the longest 2.4 to 2.6 in head in adults, usually 

 bor- 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. 



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 lowland 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 

 with 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 systems only near the mouths of those streams. 

 Its general distribution in the smaller rivers, and in lakes and 

 ponds of the bottom-lands, brings it also into contact with the 

 crappies. Its associative coefficient is 2.35 for the green sun- 

 fish 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. 



FIG. 63 



and flhy 

 membranous 

 der. 



