500 COXURIBUTIOXS TO NORTH AMERICAN ICHTHYOLOGY IV. 



line; a black spot at .the base of the caudal; fins barred. Head 4; 

 depth C. D. XY-15; A. II, 9; Lat. 1. 02. L. 6-8 inches. Great Lakes 

 and streams of the South and West; the largest of the darters. 



(Sciania caprodes Rafinesqne, Amcr. Month. Mag. 1818, 534: Pileoma semifascialum 

 DeKay, New York Fauna Fish. 1842, 16: Etheostoma caprodex, nebulosa, semifaxciata, 

 and bimaculata Storer, Synop. Fish. N. A. 270-272; Girard, Proc. Acad. Nat. Sci. Phila. 

 1859, 06: Pileoma semifasciatum Giinther, i, 76: Pileoma caprodes Vaillant 1. c. 43; 

 Jordan, Man. Vert. 220: Pileoma carbonaria Baird & Girard, Proc. Acad. Nat. Sci. 

 Phila. 1853, 387: Pileoma carbonaria Giiuther, i, 76: Pileoma carbonaria Girard, 1859, 

 10: Percina carbonaria Girard, Proc. Acad. Nat. Sci. Phila. 1859, 67; the latter a 

 variety from Texas with the fins mostly higher.) 



Var. manitou Jordan. 



Space in front of spinous dorsal naked ; lateral bars short, more or 

 less confluent, each one not meeting its fellow of the other side across 

 the back; otherwise essentially as in the preceding, with which it inter- 

 grades. Chiefly northwestward; abundant in Wisconsin. Examples 

 intermediate between caprodes and manitou from Potomac Elver (Bean; 

 Jomj] and Illinois (Forbes). 

 (Percina manitou Jordan, Proc. Acad. Nat. Sci. Phila. 1877, 53.) 



261. AtVORDIUS Girard. 

 Black-sided Darters. 



(Ethcostoma Agassiz; not of Rafinesque.) 

 (Girard, Proc. Acad. Nat. Sci. Phila. 1859, 63: type Alvordins maculatus Girard.) 



Body rather elongate, little compressed. Mouth rather wide, ter- 

 minal, the lower jaw included, the snout above not protruding beyond 

 the premaxillaries, which are not protractile. Teeth on vomer, and 

 usually on palatines also. Gill-membranes separate. Scales small, 

 ctenoid, covering the body. Belly with a median series of enlarged 

 spinous plates, which fall off, leaving a naked strip; sides of head 

 scaly or not. Lateral line complete. Fins large, the soft dorsal smaller 

 than the spinous or the anal. Anal spines 2; dorsal spines 10-15. 

 Vertebrae 22 + 22 (A. aspro}; 17 + 22 (A. wide*). Coloration bright; 

 sides with dark blotches. The most active and graceful of the darters. 



(Dedicated toMaj. 15. Alvord, who discovered "Alvordius maculatus" at FortGratiot, 

 on Lake Huron.) 



a. Vertebrae more than 40; dorsal spines 11 to 15; palatine teeth present. (Alcor- 



dius.) 

 b. Cheeks, opercles, and ante-dorsal region entirely scaleless; head very long and 



large; lat. 1. 75-80 macroccphalua. 



bb. Checks covered with line scales; npereles with larger ones. 



c. I lend very slender, with long acuminate ninz/le; .jaws nearly equal; space be- 

 fore dnis.il scaled; lat. 1. (55-70; lateral blotches small, quadrate. 



plioxoccplialus. 

 cc. Head stouter, with wider muzzle; lower jaw included aspro, nevisensis. 



