264 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
The species is gracefully sub-fusiform in its profile, the depth, in advance of the dorsal, being 
equal to the fifth of the entire length, in which the head itself enters about five times. The eye 
is very large, its diameter entering three times and a half in the length of the side of the head. 
D 2, 8 + 1; A 2, 9 ; C 8, 1, 9, 8, 1, 9 ; V 1, 8 ; P 1, 14. 
The tips of the pectoral fins are nearly at the same distance from the insertion of the ventrals 
as the tips of the latter are from the origin of the anal fin. 
The dorsal region is reddish brown, the sides being silvery and the abdomen yellowish. A 
black streak may be seen along the upper edge of the silvery zone of the flanks. Fins oliva¬ 
ceous ; rays tinged with greyish. 
References to the figures. —Plate LIX, fig. 1, represents Plargyrus boivmani, size of life. Fig. 
2, a section of the body across the line of greatest depth. Fig. 3, a dorsal scale. Fig. 4, a scale 
from the lateral line. Fig. 5, a scale from the abdominal region. 
List of specimens. 
Catal. 
No. 
Cor. No. 
of teeth. 
No. of 
spec. 
Age. 
Locality. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
65 
2672 
i 
Adult. 
Sweetwater fork of Platte 
(Nebraska) river. 
1852 
Alcoholic. 
CYPRINELLA, Girard. 
Gen Char. —Body very much compressed, either elongated and sub-fusiform, or else with the dorsal and abdominal outlines 
rather arched. The head is of moderate size, sub-conical, the snout generally protruding beyond the lower jaw. Mouth small, 
its gape slightly oblique, and sub-terminal. No barbels. Eyes moderate. Isthmus narrow. Tail tapering ; caudal fin furcated. 
Insertion of ventrals opposite or slightly in advance of the anterior margin of dorsal fin. Scales large, else of moderate develop¬ 
ment, imbricated, much higher than long, with radiating furrows upon their posterior section only. Lateral line forming a 
downwards curve beneath the middle of the flanks. Pharyngeal bones resembling those of Plargy'us. The teeth are slender and 
compressed, of the raptatorial kind of the hooked type, slightly hooked, without grinding surface, instead of which, a sharp ridge 
inconspicuously crenated, and disposed upon a double row of one and four in the following manner : 1 | 4—4 | 1. 
Syn. — Cyprinella, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 196. 
Had the name of Hypsolepis not been preoccupied to designate another genus, it might have 
been applied with great propriety to the species of the present genus, since the fishes herein 
included possess that curious character of having the scales higher than long. They replace in 
the southwest the Plargyri of more northern climes. Though generally smaller than the species 
of Plargijrus, some do resemble the latter in a very striking manner, whilst others are much 
shorter and deeper in proportion. The chief differences between the present genus and Plar¬ 
gyrus is to be found in the pharyngeal teeth and the position of the ventrals. 
To Moniana it bears more striking resemblances and real affinities. The position of the 
ventral fins is the same ; the pharyngeal bones are alike also ; the teeth are of the same general 
pattern, hut disposed upon a double series in Cyprinella, and upon one only in Moniana. More¬ 
over, in Cyprinella the snout generally protrudes beyond the lower jaw, though the mouth is 
sub-terminal and its gape slightly oblique. 
