168 



FISHES OF ILLINOIS 



back a rich green, darkest at edges of scales ; below this a narrow and more 

 or less indefinite band of much lighter green, extending forward on iris 

 above pupil and on opercle as yellowish ; passing forward through pupil 

 and ending behind in a faint caudal spot, is a more or less indistinct dark 

 lateral band; lower part of sides and belly yellowish to pearly gray; sides 

 everywhere with coppery and greenish reflections; on each side of head 

 behind eye a spot of pale red about size of pupil, most brilliant in spring 

 males; a curved dusky bar behind opercle; dorsal and caudal fins with 

 membranes orange except at tips, the edges being bluish gray ; anal orange 

 in the membranes; other fins plain; breeding colors brighter, red spots on 

 sides of head accentuated in males; very young specimens with a promi- 

 nent black lateral stripe passing around snout forward and ending behind 

 in a pronounced caudal spot. Head 3 . 6 to 3 .;8 in length, conical, top of 

 head and cheeks quite rounded ; width of head 1 . 8 to 2 ; interorbital space 



Fig. 44 



2.6 to 2.9; eye very small, 4 . 1 to 5 . 6 in head; nose sharp, scarcely de- 

 curved, 2.4 to 2.9; mouth rather large, subtermina'l, not very oblique, 

 the tip of the upper lip about half way between lower margin of orbit and 

 lower edge of cheek; maxillary 3 to 3 . 6 in head, not quite reaching to 

 front of eye; lower jaw shorter than upper; breadth of isthmus nearly 

 equal to diameter of orbit; barbel as a rule evident, though usually not 

 projecting beyond cheek, occasionally discernible only with difficulty. 

 Teeth variable, usually 4-4 in our specimens, though not infrequently 1, 

 4-4, 1 or 0; on pharyngeal, jaws from eight well-preserved specimens, 

 which were all carefully examined for lost or broken teeth, the following 

 combinations were found: 1, 4-4, 1;0, 4-4, 1; 1, 4-0, 3;0, 4-1, 3;0, 2-1, 4; 

 0, 2-1, 3; intestine 1.1 to 1 .4 in length of head and body; peritoneum 

 dusky. Dorsal fin with 8 rays, placed almost exactly over the ventrals, 

 a little nearer base of caudal than muzzle; longest dorsal ray 1 . 3 to 1 . 4 in 

 head; anal rays 7 ; pectorals somewhat over % to ventrals; ventrals to vent 

 in males, short of it in females. Scales 6 or 7, 39 to 44, S ; 17 to 22 rows 

 before dorsal fin; lateral line complete or nearly so, gently decurved ante- 

 riorly . 



This fish is of particular interest to us because of the peculiar- 

 ity of its distribution in this state. Although it occurs throughout 

 the Great Lakes from Michigan to Ontario, and from Wyoming to 



