FISHES-PERCIDAE—CALLIURUS DIAFHANUS. 
13 
List of specimens. 
Catalogue num¬ 
bers 
No. of specimens. 
Sex and age. 
Localities. 
When collected. 
Whence and how obtained. 
Original numbers. 
Nature of speci¬ 
mens. 
Collected by— 
281 
1 
Adult -. 
Leon river, Texas_ 
1853 
Lieut. Whipple_ 
11 
Alcoholic 
373 
2 
Young . 
Rio Medina, Texas_ 
1853 
__-_do_ 
18 
_do_ 
.do 
110 
1 
_do_ 
Dry creek, Texas_ 
1854 
Mai or Emory___ 
57 
_„ _-do.-_ 
_.do 
411 
1 
-.-do. 
San Pedro creek, Texas . . 
1854 
__do_,_ 
58 
___-do._ 
2. CALLIURUS DIAPHANUS, Grd. 
Plate IV, Figs. 1 — 4. 
Spec. Char. —Mouth large ; gape oblique upwards. Posterior extremity of maxillary extending to a vertical line drawn in 
advance of the pupil. Eye large. Insertion of ventrals situated posteriorly to the base of pectorals, and the origin of the 
dorsal ; their tips overlapping the vent. Scales large. Greyish olive above ; yellowish or whitish beneath. Soft portion of 
dorsal and anal fins provided with a black spo . 
Syn. — Calliurus diaphanus, Gr . in Proc. Acad. Nat. Sc. Philad. November 1857. 
The general form of this species is more slender than C. melanops, 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, hut 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 palatine 
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 C. melanops. Slender and 
exiguous scales may he 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 hack as the ventrals. The formula of the rays is as 
follows: 
Br. VI: VI; D X, 11; A III, 10 ; C 4, 1, 8, 7, 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 
