AMBLOPLITES — ROCK BASS 243 



AMBLOPLITES RUPESTRIS (Rafinesque) 

 (rock bass; redeye; goggle-eye) 



Rafinesque, 1817, Amer. Month. Mag., 120 (Bodianus). 



J. & G., 466; M. V., 115; B., I, 10; *J)& E., I, 990; X., 37; T„ 44; F , 69- F F , I 

 3, 44; L., 23. y Ol A ^Ajh J 



Length 8 to 10 inches; bodjy oblong, rather robust and only moder- 

 ately compressed; profile scarcely angled at nape; depth 2.2 to 2.S; 

 greatest width about 2 in greatest depth; depth caudal peduncle 1 . 12 to 

 1 . 20 in its length. Color of upper parts olive, with black mottlings and 

 brassy reflections; each scale of sides with a central squarish black 

 spot on band, these forming longitudinal stripes traversing length of 

 fish, being most prominent below the lateral line; belly bluish white with 

 darker punctulations, forming a spot on each scale; breast specked with 

 fine black dots and with some blue, green, or reddish; cheeks and opercles 

 with brassy luster; a dark opercular spot; iris maroon before and behind 

 pupil, plum-colored above and below, and edged with gold; median fins 

 amber with brown mottlings (in handsome irregular bars) and faint edg- 

 ings of black; ventrals opaque whitish with brown specks ; pectorals trans- 

 parent amber, dusky in males ; young irregularly barred and blotched 

 with black. Head rather large, 2.6 to 2.8, the profile little angled 

 above eye; width of head 1.9 to 2.13 in its length; interorbital space 

 3.7 to 4.3 (usually under 4) ; eye 3 . 5 to 4 ; nose 3.4 to 4.1; mouth 

 large, oblique, maxillary past middle of orbit, 2.1 to 2.4 in head; a 

 single patch of teeth on tongue; operculum emarginate, the flap not 

 prolonged; gill-rakers few, 7 to 10, rather long,. strong, and stiff. Dor- 

 sal XI (occasionally XII), 10-12 (usually 10), rather long and low, its 

 longest spine 3.25 to 3.S in head; length of base of dorsal about 1.4 

 times length of anal; caudal emarginate; anal VI, 10-1 1 ; ventrals to vent 

 or somewhat past it, sometimes nearly to first anal spine in males; pec- 

 torals to first anal spine, 1 . 8 to 2 in head. Scales 6 or 7, sometimes 

 8, 39-43, 11 or 12 (or 13) ; lateral line usually complete; scales on cheeks 

 in 7 or 8 rows. (i J2| 



This large and handsome member of the sunfish family reaches a 

 length of a foot and a weight of a pound to a pound and a half, 

 although its average we'ght probably does not exceed half a pound. 

 It is, with us, mainly a northern species, having been taken from but 

 four localities in southern Illinois, and not at all in the lower Illi- 

 noisan glaciation. This limitation of its range is accounted for by 

 its decided preference for clear rocky streams, its coefficient fo 

 swift water (3 . 66) being the largest in our list of sunfishes. It has 

 occurred to us most abundantly in rivers of medium size (2 . 96) 

 and about half as frequently in creeks (1.44), its frequencies in 

 other situations being comparatively insignificant. This peculiarity 

 of local preference tends to separate it from the other members of 



)v 



