FISHES—CYPRINIDAE—HYBORHYNCHUS TENELLUS. 
231 
HYBORHYNCHUS PERSPICUUS, Grd. 
Plate LII, Pigs. 16—20. 
Spec. Char.— Head constituting about the fifth of the total length. Eye sub-elliptical, its diameter entering three times in 
the length of the side of the head. Greatest depth of the body nearly equal to the length of the head. Caudal fin entering 
five times and a half in the total length. Insertion of ventrals situated under the anterior margin of the dorsal. Scales 
anteriorly sub-truncated. Reddish brown above, sulphur yellow beneath ; lateral line minutely dark spotted. A black spot at 
the base of the caudal, and at the anterior margin of the dorsal also. 
Svn. — Hyborhynchus perspicuus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 179. 
The head is contained five times and a quarter in the total length, instead of constituting 
the sixth part of it, as in H. notatus. The mouth and eye, both, are a good deal larger than 
in the latter species. The horizontal diameter of the eye, which is sub-elliptical, is contained 
about three times in the length of the side of the head : less than once in advance of the orbit. 
The insertion of the ventrals is situated immediately under the anterior margin of the dorsal. 
The caudal fin is more deeply furcated than in H. notatus. 
D 2, 9 ; A 2, 7 ; C 10, 1, 9, 8, 1, 8 ; Y 9 ; P 14. 
There is a very minute rudimentary ray at the anterior margin of both the dorsal and anal, 
followed by a second, about half the height of the fin. 
The scales are much deeper than high, anteriorly suh-truncated, with radiating furrows upon 
the posterior section only. The lateral line is nearly median from head to tail, being but 
slightly deflexed at its anterior initial point. 
The upper region and the flanks are reddish brown ; the abdomen exhibiting a sulphur 
yellowish tint. The lateral line is dotted with greyish purple, more distinct towards the base 
of the caudal, upon which a dark spot exists. The fins are yellowish ; a black spot being 
observed upon the anterior margin of the dorsal below the middle of the height. The upper 
portion of the dorsal and the external margin of the caudal are greyish. 
References to the figures. —Plate LII, fig. 16, represents Hyborhynchus perspicuus , size of life. 
Fig. 17 is a section of the body across the line of its greatest depth. Fig. 18, a scale from the 
dorsal region. Fig. 19, a scale from the lateral line. Fig. 20, a scale from the abdominal 
region. 
List of specimens. 
Catal. 
No. 
Cor. No. 
of teeth. 
No. of 
spec. 
Locality. 
"When 
collected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
144 
2722 
22 
Arkansas river near Fort Smith. 
1853 
Lt. A. W. Whipple.. 
Alcoholic. 
Dr. Geo. G. Shumard 
2. HYBORHYNCHUS TENELLUS, Grd. 
Spec. Char. — Head entering about five times and a half in the total length. Eye large, sub-circular; its diameter being 
contained somewhat over three times in the length of side of head. Greatest depth of the body less than the length of head. 
Caudal fin constituting about the sixth of the total leDgth. Insertion of ventrals situated somewhat in advance of the anterior 
margin of the dorsal. Reddish brown above ; yellowish beneath. 
Syn .—Hyborhynchus tenellus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 179. 
It is more slender and more compressed than even H. perspicuus. The head is very much 
depressed, sub-conical, hence appearing quite small; it is contained five times and a half in the 
