APRIL, 1910. FISHES OF CHICAGO MEEK AND HILDEBRAND. 267 



to dusky; scales large, 30 to 40 in lateral series; not smaller on an- 

 terior part of body. 



a. Scales moderate, fewer than 40 in the lateral series ; fewer than 

 20 scales in a series between nape and dorsal fin. 



b. Anal fin with 7 to 9 rays; origin of dorsal fin near middle of the 

 body. 



c. Scales on sides not or scarcely deeper than long. 



d. Body subterete, not much compressed; tip of first ray of 

 dorsal. fin reaching past tip of last ray when the fin is deflexed. 



e. Sides with a distinct dark lateral band prominent on sides of 

 head and on snout; lateral line incomplete. 



f. Mouth oblique, partially or entirely above lower margin of 

 black lateral band; origin of dorsal nearer tip of snout than 

 base of caudal ; snout pointed. 



g. Mouth very oblique, making with the vertical an angle of less 

 than 40; anterior margin of lower jaw on level with upper 

 border of lateral band. ano genus, 268 



gg. Mouth less oblique, the angle with the vertical more than 40; 



anterior margin of lower jaw on level with middle of lateral 



band. heterodon, 268 



ff. Mouth nearly horizontal, its gape wholly below lateral band; 



origin of dorsal fin midway between tip of snout and base of 



caudal; snout blunt. cayuga, 269 



ee. Sides without distinct lateral band; lateral line complete; snout 



blunt; mouth little oblique, 

 h. No dark spot at base of caudal ; 1 2 to 1 5 scales before dorsal fin ; 



maxillary 2.8 to 3.7 in head, 

 i. Interorbital broad, 2.5 to 2.9 in head; 12 to 14 scales before 



dorsal fin; maxillary 3.3 to 3.7 in head. blennius, 270 



ii. Interorbital narrow 3.0 to 3.6 in head; 13 to 15 scales before 



dorsal; maxillary 2.8 to 3.4 in head. jejunus, 270 



hh. A prominent dark spot at base of caudal; 15 to 1 8 scales before 



dorsal; maxillary 3.7 to 4.5 in head; interorbital 2.5 to 2.9. 



htidsonius, 271 

 dd. Body compressed; tip of last ray of dorsal not reaching tip of 



last ray when the fin is deflexed. whipplii, 272 



cc. Scales on sides deeper than long. cornutus, 272 



bb. Anal fin. with 10 to 12 rays; origin of dorsal fin much nearer 



base of caudal than tip of snout, 

 j. Head short, 4^3 in length of body; body slender, its depth $% 



in length. atherinoides , 273 



