282 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
The dorsal region is light reddish brown and yellowish white beneath ; the middle of the 
flanks is silvery. The fins being unicolor, of a light olive. 
List of specimens . 
Catal. 
No. 
Cor. No. of 
teeth. 
No. of 
spec. 
Sex and age. 
Locality. When col¬ 
lected. 
Whence obtained. 
Orig’l 
No. 
Nature of 
specimen. 
Collected by— 
60 
2668 
10 
Adult and 
young. 
Rio Seco, tributary to Rio 1853 
Nueces, Texas. 
Lt. A. W. Whipple.. 
19 
Alcoholic. .. 
Dr. C. B. Kennedy. 
3. LUXILUS LUCIDUS, Grd. 
Plate LX, Figs. 9—12. 
Spec. Char —Body rather elongated, sub-fusiform in its outlines. Head moderate sized, contained five times in the total 
length. Snout sub-conical, tapering ; gape of the mouth somewhat oblique ; posterior extremity of maxillar bone extending to 
a vertical line drawn in front of the orbit. Eye well developed ; its diameter entering three times and a half in the length 
of the side of the head. Anterior margin of dorsal fin somewhat nearer the tip of the snout than the insertion of the caudal. 
Greyish brown above ; yellowish beneath. Fins unicolor, assuming the tint of the region to which they belong. 
Syn.— Luxilus lucidus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 203. 
The general form resembles that of L. seco. The head, however, is contained but five times 
in the length of the side of the head. The mouth is a good deal larger, whilst the eye is 
smaller. The dorsal fin is much higher than long ; its upper edge being sub-convex. The 
anal is but a little deeper anteriorly than long ; its lower edge is sub-concave, and its anterior 
margin nearer the fork of the caudal than the isthmus. The caudal itself is somewhat longer 
than the head, hence it is contained short of five times in the total length. The origin of the 
ventrals is nearer the extremity of the snout than the insertion of the caudal; their posterior 
edge is rounded off, or sub-convex, and their tips overlap the vent without reaching quite the 
origin of the anal. The pectorals are sub-lanceolated ; their extremities not extending as far 
as the insertion of the ventrals. The following formula gives the number of the rays of the 
various fins. 
D 2, 8 + 1 ; A 2, 10 + 1; C 9, 1, 8, 8, 1, 10 ; V 8 ; P 12. 
The scales are rather large, very much deeper than long, anteriorly sub-truncated, posteriorly 
rounded, and tapering superiorly and inferiorly. The radiating furrows are but few and 
occasionally obsolete. The lateral line being very much deflexed upon the abdominal region. 
The upper region is greyish brown, whilst the inferior region is yellowish, else of a dull 
whitish tint. The middle of the flanlc somewhat metallic white. The vertical fins are greyish ; 
the ventrals and pectorals being yellowish. 
References to the figures. —Plate LX, fig. 9, represents Luxilus lucidus , size of life ; fig. 10 is 
a dorsal scale ; fig. 11, a scale from the lateral line ; and, fig. 12, a scale from the abdominal 
region. 
List of specimens. 
Catal. 
No. 
No. of 
specs. 
Age. 
Locality. 
When 
collected. 
Whence obtained. 
Orig. 
No. 
Nature of 
specimen. 
Collected by— 
55 
12 
A.&Y 
Coal creek, tiibutary to south 
fork of Canadian river. 
1853 
Lt. A. W. Whipple. 
VI 
Alcoholic. 
H. B. Mollhausen. 
56 
12 
. .do.. 
Twenty miles west of Choctaw 
Agency. 
1853 
XVI 
