CYPEINID^. 57 



it. Rudimentary dorsal ray attached : 

 d. Teeth not molar, in one or two rows : 

 e. Maxillary without barbel : 

 /. Teeth in the principal row 4-4 : 



g. Alimentary canal elongate, about four times length of body ; teeth one- 

 rowed, cultriform, with oblique grinding surface and little or 

 no hook; premaxillary projectile; lips attenuate, without 

 sheath ; scales large : 

 h. Lateral lino almost wanting; mouth oblique ; dorsal in front of ven- 



trals COLiscus, 5. 



Iih. Lateral line complete ; mouth horizontal; dorsal over ventrals : 

 — . Teeth elongate with narrow grinding surface and no hook; body 



elongate Hybognathus, 6. 



. Teeth short, with rather broad grinding surface and slight hook ; 



body short and rather stout; size small Dionda, 7. 



gg. Alimentary canal short, about as long as body ; teeth raptatorial, 

 usually strongly hooked : 

 i. Teeth with grinding surface developed, not crenate : 

 j. Dorsal fin beginning above ventrals (i. e., above some part of base 

 of ventrals) ; anal basis short : ^ 



— . Scales small, much longer than deep, with much of the surface ex- 

 posed; body stout, compressed; teeth one-rowed, little hooked, 

 the uppermost standing out above the surface of the bone ; 



size large ..(Subgenus?) Algansea,* 8. 



. Scales large, about as long as deep, the usual surface exposed; 



teeth one- or two-rowed, pretty strongly hooked ; size usually 



quite small (Subgenus?) Hybopsis, 9. 



. Scales large, much deeper than long on the sides, the ex- 

 posed surfaces very narrow ; teeth one or two-rowed, strongly 



hooked ; size moderate or large ..., LuxiLUS, 10. 



jj. Dorsal iin beginning entirely behind ventrals, between ventrals 



and anal ; anal basis elongate Lythrurus, 11. 



ii. Teeth with the edges crenate ; dorsal fin beginning over middle or 

 last rays of ventrals ; scales closely and smoothly imbricatetl; 

 teeth one-rowed {Montana) or two-rowed (Ct/prinella), 



Cyprinella, 12. 

 Hi. Teeth with edges entire and without grinding surface : 

 fc. Lips thin, normal ; lateral line complete : 

 i. Species of small size and weak organization, with the mouth little 

 cleft : 

 m. Scales comparatively thick, closely and smoothly imbricated, 

 so that the exposed surfaces are higher than long; dorsal fin 

 beginning opposite between first and last ray of ventrals, rarely 

 slightly posterior ; mouth subinferior, somewhat oblique ; 

 males in spring developing a satin-white pigment in. the tips 

 of the vertical fins and in the skin of the abdomen ; snout 

 tuberculate; colors brilliant, pigmented, 



(Subgenus?) Photogenis, 13. 

 mm. Scales thin, much exposed ; no white satiny pigment (except 

 in Codomaf): 



* In A. tincella, the type of Algansea {Leuciscus iincella C. T. V., Hist. Nat. des Poissons 

 svii, 323), the teeth are said to be 4-4. In some species referred to Algansea, they are 

 5-5. These I refer for the present to Mgloleucus, from the type of which genus they 

 differ in having but one row of teeth. 



