284 FISHES. 



grinding surface; alimentary canal elongate, four 

 times the length of body or more ; prernaxillaries 

 projectile; lips attenuate, without sheath; scales 

 large. 



/. Lateral line almost wanting; mouth oblique; dor- 

 sal in front of ventrals. . . . COLISCUS, 4. 

 ff. Lateral line complete ; mouth horizontal ; dorsal 

 over ventrals. . . . HYBOGNATHUS, 5. 

 ee. Teeth raptatorial, more or less strongly hooked ; ali- 

 mentary canal usually short, about as long as body 

 (in Notemigonus and Chrosomm somewhat elongate.) 



g. Lateral line complete (rarely obscure or wanting on 



the last five or six scales.) 

 h. Teeth in the principal row 4 4. 

 i. Teeth with masticatory surface developed. 

 ,;. Dorsal fin beginning above some part of base 

 of ventrals ; anal basis short, its rays seven 

 to nine. 



k. Scales normal, the usual surface exposed, 

 little if any higher than long; species 

 usually of small size and weak organiza- 

 tion HYBOPSIS, 6. 



kk. Scales much deeper than long, closely and 

 smoothly imbricated on the sides, so that 

 the exposed surfaces are very narrow. 



LUXILUS, 7. 



jj. Dorsal fin beginning entirely behind ventrals, 



between ventrals and anal ; anal elongate, of 



ten to twelve rays; (small, elongate species 



with the mouth oblique, the teeth 2, 4 4, 2, 



and a black sttot at base of dorsal fin in front.) 



LYTHRURUS, 8. 



ii. Teeth without masticatory surface. 



I. Lips thin, normal ; opercular and rnandibul- 

 ary bones without externally visible muc- 

 ous chambers. 

 m- Dorsal fin beginning entirely behind 



