246 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
Catal. 
No. 
No. of 
spec. 
Age. 
Locality. 
When 
collected. 
Whence obtained. 
Orig. 
No. 
Nature of 
specimen. 
Collected by— 
182 
i 
Adult. 
1853 
Dr. A. L. Heermann. 
183 
8 
A.&Y. 
1855 
138 
242 
1 
Adult. 
Sacramento river, near Fort 
Reading, Cal. 
1855 
Lt. R. S, Williamson. 
Dr. John S. Newberry 
: ■ 
2. POGONICHTHYS SYMMETRIES, B. & G. 
Spec. Char. —Head constituting the fifth of the total length. Snout rounded and sub-conical. Gape of mouth somewhat 
arched ; lower jaw shorter than the upper. Posterior extremity of the maxillary corresponding to a vertical line drawn behind 
the nostrils. Anterior margin of dorsal fin nearer the insertion of the caudal than the extremity of the snout. Insertion of 
ventrals placed in advance of the anterior margin of the dorsal, and somewhat nearer the insertion of the caudal than the tip of 
the snout. Lobes of caudal fin equally developed. Dark greyish brown or blackish above ; yellowish golden beneath. 
Syn. —Pogonichthys symmetricus, B. & G. in Proc. Acad. Nat. Sc. Philad. VII, 1854, 136.— Grd. in Proc. Acad. Nat. Sc. 
Philad. VIII, 1856, 188. 
The specimens before us being in a rather poor state of preservation, a description of the 
species can hardly be drawn with accuracy. The size of the largest one is about four inches and 
a half in total length ; the profile of the body is sub-fusiform, very much compressed, and 
gracefully elongated. The head constitutes the fifth of the total length. The eye is large, its 
diameter being contained less than four times in the length of the side of the head. The lobes 
of the caudal fin are symmetrical. The anterior margin of the dorsal is equidistant between the 
extremity of the snout and the tip of the central rays of the caudal. The lateral line forms a 
gentle curve, convex downwards, upon the middle of the abdomen, and nearer the insertion of 
the ventrals than the base of the dorsal. The insertion of the ventrals is situated in advance of 
the anterior margin of the dorsal, a character which will at once enable us to distinguish this 
species from P. inaequilobus. 
The scales are moderate, longer than deep, anteriorly sub-truncated, posteriorly rounded, 
with radiating furrows upon their posterior section only. 
The upper regions are dark greyish or blackish brown, whilst the inferior regions are of a 
yellowish golden tint, the upper part of the sides being mottled with yellow and the lower part 
dotted with black. The dorsal and caudal are greyish olive ; the other fins, greyish orange. 
List of specimens. 
Catal 
No. 
Cor. No. 
of teeth. 
No of 
spec. 
Locality. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
191 
2749 
5 
Fort Miller, San Joa- 
quim valley, Cal. 
1853 
Lt. R. S. Williamson.... 
Alcoholic. 
Dr. A. L. Heermann. 
3. POGONICHTHYS ARGYREIOSUS, Grd. 
Spec. Char. —Head constituting the fifth of the total length. Snout sub-conical ; gape of mouth nearly horizontal; lower 
jaw shorter than the upper. Posterior extremity of maxillar bone reaching a vertical line drawn at the anterior rim of the orbit. 
Anterior margin of dorsal fin equidistant between the extremity of the snout and the insertion of the caudal. Insertion of ven¬ 
trals somewhat behind the anteiior margin of the dorsal, and nearer the base of the caudal than the tip of the snout. Lobes of 
caudal fin equally developed. Rufous brown above ; silvery beneath. 
Syn. —Pogonichthys argyreiosus, Grd. in Proc. Acad. Nat. Sc. Philad. VII, 1854, 154 ; VIII, 1856, 188. 
