62 U. S. p. R. R. EXP. AND SURVEYS ZOOLOGY — GENERAL REPORT. 



LEIOCOTTUS, Girard. 



Gerf. Ch<r — Head perfectly smooth ; spines upon the preopercle only. Mouth moderately cleft ; jaws equal. Teeth upon 

 the premitxillaiies, dentaries, and front of vomer ; none on the palatines. Barbules at the maxillaries. Gill openings con- 

 tinuous under the throat ; branchiostegal rays, five. Dorsals nearly contiguous upon their bases. Ventrals inserted backwards 

 of the base of the pectorals. Caudal posteriorly subtruncated. Skin perfectly smooth, bearing neither prickles nor scales. 

 Lateral line well marked, and continuous from head to tail. 



SYS.—Laocollus, Grd. Proc. Acad. Nat. Sci. Philad. VIII, 1856. 133. 



This genus is allied to Lepiocottus, of which it has the general physiognomy. It is, however, 

 distingui.slied from it by a smaller mouth and equal jaws ; by the absence of teeth upon the 

 palatine bones, the continuity of the gill openings, and the presence of five brancliiostegals, 

 instead of six. It diflers from Scorpaenichthys by a smooth head and the absence of teeth on 

 the palatine bones. 



LEIOCOTTUS HIRUNDO, Grd. 



Plate XVI, Figs. 2 & 3. 



Spec. Char. — Snout declivous and rather pointed; posterior extremity of maxillary provided with two or three barbules, and 

 reaching a vertical line drawn a little beyond the anterior rim of the orbit. Superior regions blackish brown ; whitish under 

 the abdomen, and yellow under the tail. 



Syn.— Z,e!oro«m hintndo, Grd. Proc. Acad. Nat. Sci. Philad. VIII, 1856, 133. 



The general aspect of this species is elongated ; sub-fusiform when viewed in profile. The 

 body is compressed, deeper than broad upon its whole length. The head enters about three 

 times in the length of the body and caudal fin ; its upper surface is depressed, nearly flat ; the 

 fronto-nasal region very declivous, and the snout prominent. The mouth is but moderately cleft J 

 the posterior extremity of the maxillary upon which two or three thread-like barbels may be 

 observed, reaches posteriorly a line which would be drawn a little inwardly of the anterior rim 

 of the orbit. Teeth exist upon the premaxillaries, dentaries, and front of the vomer, whilst 

 the palatine bones are smooth and toothless. The jaws are equal, and surrounded by conspicuous 

 lips. The nostrils are situated towards the upper surface of the snout, much nearer to the orbit 

 than the extremity of the snout, and preceded by a small, inconspicuous spine. The eyes are 

 large and sub-circular, approximating the upper surface of the scull. Their longitudinal diameter 

 enters about four times in the length of the side of the head. A bifurcated spine may be 

 observed upon the convexity of the preopercle, with the points turned upwards. Two smaller 

 and obtuse spines exist along the inferior margin of the same bone. 



A vertical line drawn from the origin of the first dorsal fin would strike the middle of the 

 base of the pectorals, and therefore a portion of the opercle also. It is composed of nine spiny 

 rays, the anterior one being the highest of all the dorsal rays. The second is next in size, and 

 somewhat shorter than the highest rays of the second dorsal. The remaining rays are all much 

 shorter than the second dorsal, and that portion of the fin which they constitute is convex upon 

 its upper margin. The membrane of the posterior ray of the first dorsal does not quite extend 

 to the anterior ray of the second dorsal. The second dorsal is composed of seventeen undivided 

 rays, diminishing slightly in height posteriorly. The caudal is subtruncated, composed of nine 

 bifurcated rays, and two undivided, together .with a few rudimentary ones above and below. 

 That fin forms about the fifth of the total length. The origin of the anal is situated opposite 



