HADROPTERUS — BLACK-SIDED DARTERS 289 



scales. "Coloration extremely brilliant; * * * sides with about 7 broad 

 transverse bars extending from below the lateral line on one side, across the 

 back, and down on the other side; these bars wider than the eye and con- 

 nected along lateral line by a faint black stripe; * * * spinous dorsal 

 with a dusky spot on its posterior rays, and the fins destitute of the dark 

 bars found in related species" (Jordan and Evermann). 



Represented in our collections by a single specimen, taken 

 from Rock River in 1877, still identifiable but in poor condition 

 for description. Outside of Illinois taken in the Wabash and 

 Maumee basins in Indiana, and west and southward to central 

 Iowa, Arkansas, Kentucky, and Tennessee, "in the larger clear 

 streams. " 



I 



Fig. 69 



HADROPTERUS SCIERUS Swain 



Swain, 1883, Proc. U. S. Nat. Mus, 252. 



M. V., 127 (Etheostoma); B., I, 80 (Etheostoma) ; J. & E., I, 1037. 



Length of our specimens 2 to 23^ inches*; form and appearance of H. 

 aspro; depth 6 to 6.7; greatest width J4 °f depth; depth caudal peduncle 

 2.9 to 3.1 in its length. Color essentially as in H. aspro; yellowish olive, with 

 back and upper part of sides vaguely blotched with black in longitudinal 

 pattern, and with a median lateral row of 8 or 9 large and more or less confluent 

 dark blotches; a faint central caudal spot with a smaller one above it and a 

 larger one below, the central spot more or less merged with the lower one; 

 under side of caudal peduncle with small dark blotches; suborbital bar want- 

 ing entirely in our specimens; dorsals, caudal, and pectorals faintly barred. 

 Differs from H. aspro in the presence of 3 caudal spots, the lack of the subor- 

 bital bar, and in the blotching of under side of caudal peduncle. Head 

 pointed, 4 to 4.2; width of head 2.1 to 2.4 in its length; interorbital space 

 4.7 to 4.9; eye 3.5 to 4.1; preopercle not serrulate; nose 3.6 to 3.8, short; 

 mouth smaller than in H. aspro, the maxillary scarcely reaching front of orbit, 

 the cleft 3.4 to 3.9 in head; lower jaw included; gill-membranes broadly con- 

 nected, the distance from muzzle to free posterior margin of membranes 

 about 134 times that from muzzle to back of orbit. Dorsal fin X or XII, 13; 

 spinous and soft portions separated by a distance equal to width of eye; 

 height of first dorsal 2 to 2.2 in head, second 1.7 (height of first 79 to 85 per 

 cent, of second); caudal lunate; anal II, 9; pectorals 1.1 in head; separation 

 of ventrals equal to or a little greater than their width at base. Scales 7, 



* "5 inches" (Jordan and Evermann). 



