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. anogenus, 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. caytiga, 269 



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



blunt ; mouth little oblique, 

 h. No dark spot at base of caudal ; 12 to 15 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 18 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 5X 



in length. atherinoides , 273 



