Jordan and Erermann. Fishes of North America. 203 



qq. Barbel terminal ; teeth with grinding surface ; caudal fin 

 unsymmetrical ; the upper lobe much the longer in the 

 adult, the basal caudal rays greatly developed. 



POGONICHTHYS, 113. 



pp. Maxillary without barbel. 



r. Teeth 2-rowed; usually 2 teeth in the lesser row. 



s. Teeth subconical, scarcely hooked, sharp-edged, wide apart, 

 the long limb of the pharyngeal bone elongate ; body 

 elongate ; mouth large ; lateral line complete. 



PTYCHOCHEILUS, 114. 



s. Teeth compressed, close-set, strongly hooked ; the pharyn- 

 geal bone of the usual form. 



t. Caudal peduncle slender and elongate, the caudal fin 

 widely forked, its basal rudiments much devel- 

 oped ; scales very small ; head depressed in the 

 adult. GILA, 115. 



U. Caudal peduncle stout ; basal rudiments of caudal 

 little developed. Lsuciscrs, 116. 



rr. Teeth 1-rowed, 4-5 or 5-5. 



M. Mouth of moderate size ; teeth entire. 



v. Gill rakers short and small ; body not much com- 

 pressed ; anal fin short in American species. 



BUTILUS, 117. 



w. Gill rakers slender ; body much compressed ; anal fin 

 rather long. LUXILINUS, 118. 



MM. Mouth extremely small ; teeth serrate. 



OPSOP<EODUS, 119. 



oo. Abdomen behind ventral fins compressed to a sharp edge over which 

 the scales do not pass.; abdomen in front of ventrals, reunded; 

 anal basis elongate ; dorsal posterior ; teeth 5-5, serrate or entire. 



ABRAMIS, 120. 

 nw. Teeth in the main row, 4-4, the lesser row often absent ; anal basis usually 



short. 

 iv. Maxillary without barbels. 



x. Upper jaw distinctly protractile. 



y. Scales comparatively large, 30 to 60 in lateral line. 



z. Jaws each with a hardened bony sheath ; first ray of dorsal 

 spine like, connected by membrane with the first devel- 

 oped ray; teeth 4-4. COCHLOGNATHUS, 121. 

 zz. Jaws without bony sheath. 



a'. Lower jaw with the lip thin or obsolete, not devel- 

 oped as a fleshy lobe on each side at base ; scales 

 large, 30 to 50. 



b'. Mandible, interopercle, and subopercle not cav- 

 ernous. 



<?. First (rudimentary) ray of dorsal simple, 

 detached from the first developed ray, to 

 which it is connected by membrane (pre- 

 cisely as in Pimephales and CocMognaOnw); 

 a conspicuous black spot on front of 



dorsal and on base of caudal. 



CLIOLA, 122. 



ccf. First simple ray of dorsal rudimentary and 



closely adnate to the first branched ray 



(as usual in the family). NOTROPIS, 123. 



W. Mandible, interopercle, and suborbital witli 



conspicuous, externally visible, cavern* m- 



chambers ; teeth 1, 4-4, ; scales large. 



EBICYMBA, 124. 



