1068 Bulletin 47, United States National Museum. 



TORRENTAKIA (lorrens, a swift stream): 

 o. Anal spine single as far as known; head naked or very nearly so; a black humeral , 



process or scale; snout sharp, the mouth large. 

 p. Scales 68; body and head very long and slender. A. I, 10; gill membranes separate. 



SAGITTA, 1469. 



pp. Scales 58 to 66; body rather deep, the head slender. A. I, 7 or 8; gill membranes 

 moderately connected; body with sharp cross bands. ATJSTBALE, 1470. 



oo. Anal spines normally 2. 



q. Gill membranes scarcely connected; lower jaw moderate, not projecting. 

 NIVICOLA (nix, niveus, snow; colo, to inhabit): 

 r. Fins very small, the dorsal rays VIII-9; cheeks and opercles scaly; scales 53. 



BOREALE, 1471. 



rr. Fins not very small. Dorsal spines 9 to 13; the soft rays 10 to 14. 

 RAFINESQUIELLTJS *: 



s. Dorsal fins more or less connected; last dorsal spine not longer than next 



the last; a dark humeral scale; coloration mottled; form very robust, 



the depth about 4 in length ; scales 44 to 50. POTTSII, 1472. 



OLIOOCEPHALUS (oAryos, few, small; Ke<aAij, head): 



ss. Dorsal fins well separated, the last dorsal spine short; form comparatively 



slender. 



t. Humeral region without differentiated black scale-like process; some- 

 times with a faint dark spot. 



n. Scales between spinous dorsal and lateral line 4 to 7. 

 v. Head not entirely naked. 



w. Cheeks and opercles more or less closely scaled. 



x. Scales small, about 60; soft dorsal with 10 or 11 rays; 

 body slender. IOW;E, 1473. 



xx. Scales moderate, 41 to 55; soft dorsal rays 12 or 13. 

 y. Lateral line almost or quite complete; sides in 

 male with bluish bars or blotches. 



JESSIE, 1474. 



yy. Lateral line with 30 to 35 tubes only; sides with 

 alternate yellow and dark cross bars. 



1UTEOVINOTUM, 1475. 



imo. Cheeks scaly; opercles naked; scales 54 to 61. D. X-12; 



sides with faint dark cross bars. LEPIDOGENYS, 1476. 



www. Cheeks naked or nsarly so; opercles more or less scaly; 



scales rather large, about 48; males with alternate 



oblique bars of red and blue; fins ornate. 



C^EULEUM, 1477. 



w. Head entirely naked; scales about 48; form and coloration of 

 Etheostoma cseruleum. LEPIDTJM, 1478. 



tt. Humeral region with a distinct black process or scale. 



z. Cheeks mostly naked, opercles scaly; scales about 50; body banded; 

 fins rather large. D. XII-12. TIPPECANOE, 1479. 



zz. Cheeks and opercles naked, or very nearly so. 



a'. Scales very small, 63 to 80; body everywhere much dotted 

 with black. PTJNCTULATUM, 1480. 



na'. Scales moderate, less than 62 in number. 



b'. Scales of sides not marked, each with a dark spot, these 



forming continuous stripes. 



c'. Scales 46 to 55; snout much shorter than eye, which 



is 3% in head. CRAGiNi,1481. 



cc'. Scales 45 to 50, snout as long as eye, which is 5 in 



head. OBEYENSE, 1482. 



* Named for Constantino Samuel Rafinesque, who first recognized the existence of darters in 

 the streams about the falls of the Ohio (Louisville, Kentucky). 



