ll'J4 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



The species may be divided as follows :* 



- ales not especially deeper Ilian long; not closely imbricated. 

 'Teeth 4-4 j >pecies of small size, 

 t Teeth with grinding surface more or less developed. (HYBOPSIS Cope, nou Ag.) 



(a.) .Scales in tlir la I mil Hue more than 4."> alia. saUa'i. 



a. Scales in the latmil line 43 or 44 tudltana, lauroccpJtalu, iKvmaturu. 



aa. Scales in the lateral line 32-37. 



spedruncula, indiila, frelensis, longiroslris, straminca. 

 voliH-diii, microstoma, llncolaia, miseuriensis, procne. 

 tt Teeth without grinding surface. (CLiOLA.) 



I*. A black spot on anterior edge of dorsal and one at the base of the caudal. 



vigilax. 



bb. No black spot on anterior edge of dorsal clilora, nigrotceniata. 



feet h t \vo-ro\ved. 



t Teeth without grinding surface /. colritis, stunt. 



tf Teeth with grinding surface more or less developed. (IlunsoxifS Grd.) 



salitdana, slorcriana, hudxonitt, cnryopa. 



$$ Scales deeper than long, very closely imbricated along sides of the body. 

 Te.'th4-4. 

 t Edges of teeth entire. (CoDOMA Girard.) 



t Teeth with grinding surface developed iris, jngalis. 



tt Teeth without grinding surfaee. 



a. Dorsal lin inserted notably behind ventrals ; head very short and blunt, al- 

 most round ritlata, ornata. 



aa. Dorsal fin inserted directly over ventrals; head moderate, subcouic. 



calliscma. 



l!n- premaxillary on th.- level of the pupil, the maxillary not reaching the front of the 

 pupil. Jaws e(|ual. 1'reorbital large. Scales not closely imbricated, 19 in front of 

 dorsal lin. Dorsal over ventrals. Caudal peduncle deep, lilnish, sides silvery, 

 lins plain. Head 4; depth :i. D. 8; A. 8; scales 6-4(3-4 ; teeth 4-4, with narrow 

 grinding Mirface. Lake Tnpataro, Guanajuato. 



(IInil(thi* altim Jordan, Proc. U. S. Nat. Mus. 1879,301.) 



(/<.) ('. mill,!/ ((Jiinther) J. & G. Caudal ]ieduncle not quite twice as long as deep. 

 No barbels. Snout < ilil iiscly conical, longer than the eye, which is one-fifth the length 

 of head, rpper ja\\ slighi ly o\ erlapping tin- lower. Maxillary not extending to < ye. 

 I>i>r>a! immediately behind ventrals. Fins short, r.rownish green above, minutely 

 dotted with black along the sides. Head 4; depth '.}%. D. 7; A. C; Lat. 1. 54: te th 

 4-4, long, (iirveil, \\ilh grinding Mirl'ace. Intestinal canal with lew convolutions. 

 I,.: 1 .' inclio. ( 'iicrnav.-H'a, Mexico, (diiiillitr.) 



r<il!rlilli>/x milliri (iiinthrr, vii, 484: Hndxmtitix xaUn'i .Toi'dan, 1'roc. 1'. S. N:it. M'us. 



!-;;. 226.) 



(c.) C. iir/mlii -nint'1 (Giintlier) .lor. I'.ody oblong, snout obtuse, convex, hmgi-r than 

 lhei-\.-. l-:\.- I' in In-ad. Mouth subinferior, small, t he upper jaw the' longer, max- 

 illary not reaching front of orbit. A black lateral band. Head 4J ; depth 5. D. 8 ; 



A.-: scales 6-35-3. Teeth proi.aid\ 4-4, although only 2-2 are present in one of the 



typical examples, and none at all in tin 1 others ; no c\ii!ent grinding surface. L. 4 



iliclie^. Al'i-co. Mexico. 



ruiiilif-t iiiip-nlii n'hi/ir: Ciinthcr, \\\, \~~> : i'l'mlii ni</i'nl/i n'mhi Jordan, 1'roc. T T . S. 

 Mus. 1879,22 '. 'I' I ie accidental los-i o|" tin- teeth ill t \vo of the ihree typical exa Ill- 

 pi. , \\ a- ill.- occasion of t he cstaldisbmi-nt of the nominal -en us artunJiin.) 



"Tim reader is advised to be cautious in the use of this key. Sonic characters ap- 

 pear in tin- adult only, and in other cases their presence is a question simply of 



degree. 



