ISO FISHES OP ILLINOIS 



Found in this state only from the East Fork of the Mazon 

 River, near Gardner. The identity of this Species with N. pilsbryi 

 Fowler, which was described in 1904 from the White River basin in 

 Arkansas, seems open to no question. 



Fig. 37 

 NOTROPIS JEJUNUS (Forbes) 



Forbes, 1878, Bull. 111. State Lab. Nat. Hist., I. 2, 60 {Episema). 

 J. &&., 194 (Minnilus);M. V., 60; J. & E., I, 290; F., 77; L., 18. 



A pale silver}' minnow of rather indefinite characters, in form resem- 

 bling H ybognathus nuchalis, the outline being fusiform, with dorsal and 

 -ventral contours similar, but lacking the long intestine and maxil- 

 lary protuberance of that species and with the head rather blunter. 

 .Length 2 to 2\ inches; depth 3 . 8 to 5 in length, the body deepest just 

 in front of the dorsal fin; body considerably compressed, the greatest 

 width about £ the greatest depth ; caudal peduncle somewhat shorter than 

 head, its depth 1 . 9 to 2 .4 in its length. Color pale, the sides silvery with 

 a broad plumbeous band; lateral scales rather coarsely specked with 

 black, those of back more finely specked over their entire surfaces; 

 cross-hatching most evident along lateral line and below it, where the 

 scales are pale except at outer edges ; a dark vertebral streak but no 

 caudal spot; cheeks and opercles silvery below, steel-blue to cerulean 

 above; a conspicuous splash of emerald on lateral aspect of occiput — 

 just behind eve; iris silvery with some lavender; fins all plain. Head 3 . 8 

 to 4.5 in length, squarish in transverse section at orbits, being only 

 slightly rounded above ; width of head 1 . 7 to 2 . 2 in its length ; interorbital 

 space 2 . S to 2 . 9 in head ; eye very little shorter than snout in adults, 3 . 2 

 to 3 . 8 in head; nose bluntly conic, 3.1 to 3.6; mouth moderately large, 

 very little oblique, the tip of the upper lip little above level of lower rim 

 of pupil; maxillarv 2 . 8 to 3 . 4 in head, extending hardly to front of orbit; 

 lower jaw slightly shorter than upper; isthmus less than pupil. Teeth 

 usually 2, 4-4, 2; sometimes 1, 4-4, 1 or various intermediate combina- 

 tions; grinding surface, if present, narrow and irregular; intestine .9 to 

 1 .2 times length of head and body; peritoneum silvery, with a few small 

 specks of dark color. Dorsal tin with 8 rays, occasionally 7, set as a rule 

 almost directly over ventrals and about equidistant between muzzle and 

 base of caudal; longest dorsal ray 1 . 1 to 1 .4 in head; anal rays usually 7, 

 occasionally 6 or 8; pectorals short, 1.1 to 1 .4 in head, as a rule less than 



