292 FISHES OF ILLINOIS 



also by the non-protractile maxillary, which is joined for most of its 

 length to the skin of the front of the preorbital; no teeth on vomer or 

 palatines; no enlarged ventral plates; vertebrae 42 (19+23); pyloric casca 

 4; coloration largely green. Size moderate, 3 to 5 inches; a single species. 



DIPLESION BLENNIOIDES (Rafinesque) 

 (green-sided darter) 



Rafinesque, 1819, Journ. de Physique, 419 (Etheostoma [Diplesion]). 



J. & G., 497; M. V., 125 (Etheostoma); B., I, 100; |. & E., I, 1053; X., 35 (Etheosto- 

 ma); J., 40; F., 66; L., 27 



: / , 



Length 3 inches; body elongate, neither cylindrical nor (technically) 

 compressed, but narrowed dorsally in front so that a cross-section of the 

 body is roughly triangular; back somewhat elevated in adults and profile 

 ver\' convex; ventral outline straight or slightly concave; depth 5.3 to 

 6.3; greatest width of body about | its greatest depth ; depth caudal 

 peduncle 2 . 6 to 3 . 2 in its length. Color of upper parts light olivaceous, 

 paler beneath, the belly a light creamy white; sides marked with 5 to 8 

 vertical bars of rich dark grassy green color, these continuous wit! ark 

 saddle-like back blotches;* below lateral line a row of Y-shaped blotches, 

 sometimes connected so as to form an irregular wavy or zigzag band of 

 rich green; 20 to 50 small rufous-orange spots scattered along sides in 

 irregular zigzag lines, each spot occupying the center of a scale ; head dark 

 olive-green, mottled with darker green, a dark green band passing from 

 the eye downward and forward around the upper jaw and a similar one 

 downward to a short distance behind the angle of the mouth ; suborbital 

 bar of one side usually extending beneath chin to meet the bar of the 

 other side; cheeks yellowish green, opercles dark green; head pale be- 

 neath ; pupil black, iris with some gold ; spinous dorsal with a band of 

 rufous-orange spots at its base occupying about lower third of fin, which 

 is tipped at outer margin with a narrow edge of pale blue; second dorsal 

 with row of orange spots fainter, and without outer blue edging; other 

 fins paler, greenish ; females with orange spots at base of spinous dorsal 

 less brilliant, and with these spots missing on second dorsal. Head 

 short, irregularly pyramidal, fiat and broad below, 4 to 4.6 in length; 

 width of head 1.5 to 1.9; interorbital space narrow, flat, 5.2 to 6.8 

 in head; eye roundish, high, and somewhat protruding, 3.1 to 3.6; 

 nose 3.1 to 3.7, the muzzle much decurved and projecting beyond the 

 inferior mouth; mouth small, inferior, horizontal, maxillary reaching to 

 front of orbit, cleft 3.1 to 3.6 in head; lower jaw much shorter than 

 upper; lips rather more prominent than is usual in darters; gill-mem- 

 branes connected broadly across isthmus, the distance from tip of snout 

 to free posterior margin of membranes being 1| to IJ greater than to 

 back of orbit. Dorsal fin XIII-XIV, 13-14; spinous and soft portions 

 joined or but slightly separated ; height of first dorsal 1 . 6 to 2 . 3 in head, 

 second 1.4 to 1.6 (height of first 68 to 90 per cent, of second); caudal 



*These blotches are the only part of the bars usually visible in preserved 

 specimens, showing in life as dark pigmented areas under the green of the bars. 



