FISHES PERCIDAE — CALLIURUS DIAFHANUS. 



13 



List of specimens. 



Localities. 



Leon river, Texas 



Kio Medina, Texas 



Dry creek, Texas 



San Pedro creek, Texas 



1853 



1853 

 1854 

 1854 



Whence and how obtained. 



Lieut. Whipple 



do 



Major Emory.. 

 do 



11 



18 

 57 

 58 



Nature of speci- 

 mens. 



Collected by — 



2. CALLIURUS DIAPHANUS, G r d . 

 Plate IV, Figs. 1—4. 



Spec. Char. — Mouth large ; gape obhque upwards. Posterior extremity of maxillary extending to a vertical line drawn in 

 advance of the pupil. Eye large. Insertion of ventrala situated posteriorly to the base of pectorals, and the origin of the 

 dorsal; their tips overlapping ihe vent. Scales large. Greyish olive above; yellowish or whitish beneath^ 'Soft portion of 

 dorsal and anal fins provided with a black spot. 



Stn. — Calliurus diapkanus, Grd. in Proc. Acad. Nat. Sc. Philad. November 1857. 



The general form of this species is more slender than C. nielanops, although the two species 

 resemble each other in the size of the mouth, eyes, and scales. The greatest depth is equal to 

 the length of the head. The head enters about three times and a half in the total length. 

 The mouth is not so deeply cleft as in the preceding species, but the lower jaw is quite 

 as prominent and protruding beyond the upper. The posterior extremity of the maxillary 

 extending only to a vertical line drawn immediately in advance of the pupil. The jjalatine 

 teeth constitute a very narrow band. The tongue is rather thin and perfectly smooth or 

 toothless. The diameter of the eye enters about four times and a half in the total length. We 

 observe three nasal apertures on each side, disposed upon a triangle on the left side and upon a 

 curve on the right. The external edge of the opercular bones is smooth. The branchios- 

 tegals are six on each side. 



The soft portion of the dorsal fin is more developed than in G. melanops. Slender and 

 exiguous scales may be observed upon its base, as also upon the base of the caudal and soft 

 portion of the anal fin. The insertion of the ventrals is situated posteriorly to the base of the 

 pectorals, and a little posterior also to the origin of the dorsal fin. The outermost soft ray 

 terminates into a filiform appendage which protrudes beyond the vent ; the vent itself being 

 placed at a short distance from the origin of the anal fin. The pectorals are of moderate 

 development, and do not extend as far back as the ventrals. The formula of the rays is as 

 follows : 



Br. VI : VI ; D X, 11 ; A III, 10 ; C 4, 1, 8, Y, 1, 3 ; V I, 5 ; P 13. 



The scales are large and very inconspicuously pectinated, the serratures being quite deciduous, 

 thus explaining their absence on the figures of Plate IV. The diverging furrows are quite 

 numerous, and extend upon the anterior section of the scale only. The scales themselves are 

 deeper than long, sub-truncated anteriorly, and rounded upon the remaining three edges. 



The ground color is greyish olive above ; yellowish or whitish beneath. The soft portion of 



