FISHES — CYPEINIDAE — HYBOEHYNCHUS TENELLUS. 



231 



1. HYBORHINCHUS PERSPICUUS, Grd. 

 Plate LII, Figs. 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 iu 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. 



Syn. — Hyhcrhynclms perspicvus, Ged. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 179. 



The liead is contained five times and a quarter in tlie total length, instead of constituting 

 the sixth part of it, as in H. notatus. The mouth and eye, hoth, are a good deal larger than 

 in the latter species. The horizontal diameter of the eye, which is suh-elliptical, is contained 

 aboirt 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 ; V 9 ; P 14. 



There is a very minute rudimentary ray at the anterior margin of hoth the dorsal and anal, 

 followed by a second, about half the height of the fin. 



The scales are much deej^er than high, anteriorly sub-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 Hyhorhynchus 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. 



2. HTBORHYNCHUS 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 length. Insertion of ventrals situated somewhat in advance of the anterior 

 margin of the dorsal. Reddish brown above ; yellowish beneath. 



SvN. — Hyborhynchus lenellus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 179. 



It is more slender and more compressed than even H. persjncuus. The head is very much 

 depressed, sub-conical, hence appearing quite small ; it is contained five times and a half in the 



