NOTROPIS 131 



'hh. Mouth extremely small and upturned, the maxillary scarcely reaching 

 anterior nostril, and making an angle of 20° to 30° with vertical when 



mouth is closed ; teeth 4-4 ; peritoneum black anogenus. 



ft. Black lateral stripe, if present, developed only posteriorly (not continued 



forward through eye to end of snout) . 

 i. Mouth more or less oblique, jaws subequal; lateral line distinctly decurved 

 anteriorly. A dark vertebral streak, and a plumbeous lateral band more 

 or less distinct posteriorly; scales of lateral line of average depth; length 

 2 i inches „ blennius. 



ii. Mouth little, if any, oblique, tip of upper lip below level of lower margin of 



orbit; lower-jaw distinctly shorter than upper-; lateral line nearly straight. 



phenacobius. 



ee. Scales before dorsal smaller, 17 to 19 in number; mouth inferior, lips rather 



thick; teeth 1, 4-4, 1 gilberti. 



dd. Eye very large, 2 J to 2 J in head; dark lateral stripe not developed anteriorly; 



some dusky color on chin at tip; teeth 1, 4-4, 4 ; length 3 inches 



illecebrosus. 



Cc. Large species, 4 to 6 inches in length when adult; plumbeous lateral stripe 



not continued to head ; course of lateral line not anywhere marked out by 



conspicuous dark spots above and below ea.cn pore; a broad vertebral 



streak always present; teeth 1 or 2, 4-4, 1 or 2. 

 j. A prominent black spot at base of caudal fin; scales before dorsal 18 to 20. 



hudsonius. 



jj. No black spot at base of caudal; scales before dorSal IS or 16 jejunus. 



bb. Eye small, 4 to 5 in head in adults; body more or less distinctly compressed, 

 the back sharplv rounded in front of dorsal fin; scales closely imbricated; 

 teeth 4-4 or 1, 4-4, 1. 

 k. Body very short and deep, the depth 3 to 3.3 in length; usually no dark 

 color on posterior membranes of dorsal fin; teeth as a rule 4-4, sometimes 

 1 , 4-4, 1 or *. lutrensis. 



kk. Body more elongate, depth 3J to 4 in adults; a more or less distinct black 

 blotch on last membranes of dorsal; teeth 1, 4-4, 1 whlpplii. 



aa. Anal rays 9, 10, 11, or 12; teeth 2, 4-4, 2. 

 1. Dorsal fin in front of or over ventrals; exposed portions of scales of flanks 

 notably deeper than long; a broad dark vertebral streak; anal rays 9 or 



10, usually 10 cornutus. 



11. Dorsal fin behind ventrals; scales roundish, the exposed portions not notably 



deeper than long. 

 m. Scales loosely imbricated, those before dorsal in IS to 17 series; no black 

 spot at base of dorsal. 



n. A broad dark vertebral streak; anal rays 9 or 10 pilsbryi. 



nn. Vertebral streak very narrow and usually faint. 

 o. Eye equal to or longer than snout; maxillary equal to eye; snout blunt; 



anal rays 9, 10, or 1 1 (usually 10) atherinoides. 



oo. Eye shorter than snout; maxillary 1J times eye; snout sharp; anal rays 



9 or 10 rubrifrons. 



mm. Scales closely imbricated, about 30 series in front of dorsal; a black spot 

 usually evident at front of base of dorsal; anal rays 10 to 12, usually 

 11 umbra tilis. 



