I 
228 U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY—GENERAL REPORT. 
in advance of the orbit. The fins are of hut moderate development; the insertion of the 
ventrals is situated a little posteriorly to the anterior margin of the dorsal. The formula of the 
rays read as follows : 
D2,8; A 2, 8 ; C 8, 1, 9, 8, 1, 7 ; V 8; P 14. 
The scales are large, deeper than long, with radiating furrows upon their posterior section 
only ; the lateral line following the middle of the flanks. 
The dorsal region is blackish brown ; a black streak is observed along the flanks, just above 
the lateral line, extending from a black spot at the base of the caudal, to the extremity of 
the snout. The inferior region is yellowish white ; minute black dots being spread all over the 
body. 
List of specimens. 
Catal. 
No. 
Cor. No. 
of teeth. 
No. of 
spec. 
Sex. 
Locality. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
45 
2658 
12 
<? 9 
Head waters of Rio Pecos... 
1854 
Capt. John Pope. 
Alcoholic 
Capt. Pope_ 
2. DIONDA PAPALIS, Grd. 
Spec. Char. —Body anteriorly thickisli, sub-fusiform. Head sub-conical, abbreviated, forming a little more than the fifth of 
the total length. Eye sub-circular. Gape of the mouth slightly arched; its angle not reaching a vertical line drawn in advance 
of the orbit. Caudal fin entering five times and a half in the entire length. Insertion of ventrals situated under the anterior 
margin of the dorsal. Scales moderate, deeper than long. 
Syn. —Dionda papalis, Grl>. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 178. 
The head in this species is rather small, but rounded off upon the snout; it forms a little 
more than the fifth of the entire length. The eye is sub-circular ; its diameter entering four 
times in the length of the side of the head. The body is thickish anteriorly, sub-cylindrical, 
tapering posteriorly. The dorsal and anal fins are proportionally well developed. The caudal 
is furcated ; the ventrals are inserted under the anterior margin of the dorsal. The scales are 
moderate sized, deeper than long. The coloration has been altered to a uniform black subse¬ 
quently to its immersion in alcohol with sundry other specimens. 
List of specimens. 
Catal. 
No. 
Cor. No. 
of teeth. 
No. of 
spec. 
Locality. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
39 
2653 
2 
Delaware creek, trib. of Rio Pecos.. 
1854 
Capt. John Pope. 
Alcoholic . 
Capt. Pope. 
3. DIONDA PLUMBEA, Grd. 
Plate LII, Figs. 21—25. 
Spec. Char. —Body elongated, sub-fusiform, compressed. Head sub-pyramidal, anteriorly blunt, constituting the fifth of the 
total length. Gape of mouth slightly arched, its angle not extending as far as a vertical line drawn in front of the orbit. The 
eye is large, sub-circular. The caudal fin enters about six times in the total length. Insertion of ventrals situated slightly back¬ 
wards of the anterior margin of the dorsal. Scales moderate sized, deeper than long. Greyish brown above ; whitish or 
yellowish beneath, with a black spot at the base of the caudal. 
Syn. —Dionda plumbea, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 178. 
