168 FISHES OF ILLINOIS 



depth 1.9 to 2.1 in its length. Color of top of head and 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 prominent 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 



FIG. 44 



head 1.8 to 2; interorbital space 2.6 to 2.9'; eye very small, 4.1 to 5.6 in head; 

 nose sharp, scarcely decurved, 2.4 to 2.9; mouth rather large, subterminal, 

 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 j aw 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 com- 

 binations 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, 5; 17 to 22 rows before dorsal fin; 

 lateral line complete or nearly so, gently decurved anteriorly. 



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

 liarity of its distribution in this state. Although it occurs 

 throughout the Great Lakes from Michigan to Ontario, and 

 from Wyoming to Pennsylvania and southward to North Caro- 



