CYPRINIDiE. — XXVI. 53 



back and sides dusted with dark specks. Head 4£ ; depth 5. 

 D. high, 8. A. 7 Lat. 1. 63. L. 21 Illinois R. (Lat., dusted). 



51. CHROSOMUS Rafinesque. (xpw> color; aupa, body.) 



89. C. erythrogaster Rafinesque. Red-bellied Mixnow. 



Brownish olive, with black spots on the back, a blackish band from 

 above eye, straight to the tail, sometimes breaking up in spots be- 

 hind ; another below, broader, running through eye, decurved 

 along the lateral line, ending in a black spot at base of C. ; belly 

 and space between bands bright silvery, brilliant scarlet red in 

 spring males, as are the bases of the vertical fins; females ob- 

 scurely marked. D. 8 ; A. 9. Scales 16-85-10. L. 2\. Penn. to 

 Dakota and Tenn., abundant in small clear streams; one of the 

 most beautiful of our fishes ; in high coloration the fins are bright 

 yellow. It is the most desirable of all our minnows for aquarium 

 purposes, being hardy, graceful, and gaily colored, (tpvdpos, red ; 

 yao-TTjp, belly ) 



52. HYBOGNATHUS Agassiz. (v@6s, gibbous ; yvdtios, jaw.) 



a. Teeth comparatively long, and scarcely Looked; silvery species. (ITybo- 

 gnathus.) 

 b. Suborbitals broad, the anterior, about twice as long as deep. 

 c. Mouth narrow, its cleft not reaching nearly to eye; lower jaw shorter 

 than upper, obtuse at tip. 



90. H. nuchalis Agassiz. Body rather slender; head rather 

 short, the profile evenly curved ; eye moderate, 4 in head ; lateral 

 line decurved ; 13 large scales in front of D. ; intestine 7 to 10 

 times length of body. Silvery green, sides bright silvery, with an 

 underlying plumbeous shade : fins all pale. Head 4\ to 5 ; depth 4^. 

 D. 8, A. 7. Scales 5-38-4. L. 4 to 9. N. J. to S. C, Dakota, and 

 Texas, common near large rivers. Variable ; notable varieties are 

 placita Girard, Arkansas and Missouri rivers, the eye smaller, 

 5 in head, the snout depressed and blunt, with very small mouth; 

 var. regia Girard, Potomac River, larger (7 inches long), with 

 deeper body and larger eye, 3 J in head. (Lat., pertaining to the 

 nape.) 



cc. Mouth wide, its cleft reaching about to eye; jaws subequal, the lower 

 acutish at tip. 



91. H. argyritis Girard. Silvery. Upper Missouri and Red 

 R. of North. (Lat., silvery.) 



aa. Teeth comparatively short, distinctly hooked; suborbitals very narrow; 

 plumbeous species. {Dionda Girard.) 



92. H. nubila (Forbes). Maxillary 31 in head ; snout short, not 

 very blunt ; eye 3 in head ; 1 2 scales before D. Head 41 ; depth 

 4^. Scales 5-37-3. Olivaceous with plumbeous or dusky lateral 



