236 



U. S. P. R. E EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



List of specimens. 



2. HYBOGNATHUS EVANSI, Grd. 



SPEC. CHAR. Body sub-fusiform in profile. Head sub-conical, thickish, contained about five times in the total length. Eye 

 moderate sized, sub-circular. Anterior margin of dorsal fin equidistant between the extremity of the snout and the base of 

 the caudal. Insertion of ventrals being situated posteriorly to the anterior margin of the dorsal ; is therefore nearer the base 

 of the caudal than the extremity of the snout, Caudal fin constituting the fifth of the total length. Scales anteriorly truncated. 

 Reddish brown above ; silvery on the flanks and beneath. 



&?n.Hylognathus eaansi, GRD. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 182. 



In its general aspect this species is shorter than any of its known congeners. It may easily 

 &quot;be distinguished from the preceding one by a much stouter head, more protruding snout, 

 shelving inwards and downwards, small mouth, smaller eye; the diameter of the latter entering 

 almost four times and a half in the length of the side of the head. The opercle is as long as 

 deep, sub-quadrangular, slightly emarginated behind, as in the rest of the species. 



List of specimens. 



3. HYBOGNATHUS PLACITUS, Grd. 



SPEC. CHAR. Body sub-fusiform in profile. Head sub-conical, contained about five times and a half in the total length. 

 Eye moderate sized, sub-circular. Anterior margin of dorsal fin nearer the extremity of the snout than the base of the caudal, 

 whilst the insertion of the ventrals is nearly equidistant between the same points. Scales anteriorly rounded. Greyish brown 

 above, silvery on the flanks, and dull metallic white beneath. 



S-ssHybognathusplacitus, GRD. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 182. 



The general form of the body is intermediate between H. argyritis and H. evansi. The snout 

 is thickish, but less so than in H. evansi; the mouth is also smaller. The eye is circular ; its 

 diameter being contained over four times in the length of the side of the head. The scales are 

 also larger than in H. evansi, rounded upon their anterior margin and, as usual, exhibiting 

 radiating furrows upon their posterior section only. 



The color is greyish brown above ; the middle of the flanks being greyish silver, whilst the 

 inferior region is dull metallic whitish or yellowish. 



