36 U. S. p. R. R. EXr. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



situated in advance of the base of tLe pectoral fins ; and in being provided mostly with velvet- 

 like teeth, and sometimes with canine teeth intermingled. 



The representatives of this family are all of marine habits ; those recorded below are new to 

 science, and peculiar to the fauna of our western coast. 



Like most of the percoids, they are esteemed upon European tables. How far the species 

 described below is savorous, the settlers of western America alone are prepared to tell. Its 

 compressed and thin body may not be deemed worthy of the trouble of culinary skill, unless it 

 should reach a larger size than we at present know. 



HETEROSTICHUS, Girard. 



Gev. CiiAn. — Body very compress- d, and thin posteriorly. Mouth moderate, lower jaw longest; cnnine teeth upon the 

 jaws, velvel-lilie teeth upon the vomer and palatines. Opercular apparatus without either spines or dcnticulations. Branchi- 

 ostegal rays six in number. One continuous dorsal fin, occupying nearly the whole length of the back, with its upper outline 

 variously depressed ; soft portion much shorter than the spinous. Anal fin very long, provided anteriorly with but few spinous 

 rays, and extending posleiiorly near the base of the caudal. Caudal fin slender. Scales very small. Lateral line arched above 

 the pectorals. 



Sx^.—Heleroslichus, Grd. Proc. Acad. Nat. Sc. Philad. VII, 1854, 143. 



The most prominent feature of this genus, which is allied to Percis, Pinguipes, and Per- 

 copliis, consists in its very compressed body ; also in the development and structure of its dorsal 

 fin. The latter originates near the occipital region, and extends to near the base of the caudal. 

 The line described by its upper edge is undulating, owing to the diversity of the rays composing 

 it. The extent of the anal fin, as also the reduced size of the scales, may likewise rank amongst 

 characters of no minor importance. 



So far we are acquainted with but one species of this genus, a description of which is here 

 offered, accompanied by a very accurate figure. 



HETEROSTICHUS ROSTRATUS, Grd. 



Plate XIII. 



FrEC. C'nAB. — Head conical, tapering towards the snout ; lower jaw longest. Canine teeth small and slender, disposed 

 upon one single row. Caudal fin small, posteriorly emarginated. Anal fin very long, deepest posteriorly. Articulated rays 

 of dorsal highest. Scales minute. Yellowish brown, with irregular transverse blackish blotches. A postocular, triangu- 

 lar, blackish brown blotch. 



^xs.—IIeUTOslichus rostralus, Gkd. Proc. Acad. Nat. Sc. Philad VII, 1854, 143. 



The head is rather small and sub-conical, continuous with a compressed body, anteriorly dee]), 

 tapering posteriorly to a caudal peduncle, the least depth of which is about the fourth of the 

 greatest depth. The latter, measured across the pectorals, is contained five times in the entire 

 length. The greatest width, anteriorly, is alwut the half of the greatest depth: fig. 2 will give 

 an idea of its gradual decline posteriorly. Tlie head constitutes about the fourth of the total 

 length, or a little less ; its upper outline is very much depressed and slighly concave. The 

 snout being elongated, and the mouth cleft almost to the anterior rim of the orbit. The mouth 

 is rather above the medium size, and might almost be called large. The lower jaw is the 

 longest, and protrudes beyond the upper one. The posterior extremity of the maxillarics reach 

 a vertical line passing in advance of the pupil, and are toothless. The premaxillaries are broadly 

 developed, bearing exteriorly one row of conical and slender teeth, and inwardly an oblong 

 patch (one on each, and closely approximating) of velvet-like teeth ; a patch of similar teeth 



