CYPRINIDA. — XXVL 53 
back and sides dusted with dark specks. Head 41; depth 5. 
D. high, 8. A.7 Lat. 1.63. L. 23. Illinois R, (Lat., dusted). 
51. CHROSOMUS Rafinesque. (pas, color; c&pua, body.) 
89. C. erythrogaster Rafinesque. Rep-BELLIED MINNow. 
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. 24. 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. (épvOpés, red; 
yaornp, belly.) 
52. HYBOGNATHUS Agassiz. (%8¢s, gibbous ; yrdOos, jaw.) 
a. Teeth comparatively long, and scarcely hooked; silvery species. (Hybo- 
gnathus.) 
6. 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 41. 
D. 8, A. 7. Scales 5-38-4. L.4to9. N.J.toS. 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, 33? 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 34 in head; snout short, not 
very blunt; eye 3 in head; 12 scales before D. Head 44; depth 
43. Scales 5-37-3. Olivaceous with plumbeous or dusky lateral 
