624 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io4 



Family Percophididae 



Characters common to the five species here treated: Notably- 

 elongate, slender. Head and anterior part of body depressed, the 

 width in relation to the depth gradually decreasing from head back- 

 ward, becoming somewhat compressed at caudal peduncle; ventral 

 aspect flat, especially anteriorly, forming a nearly horizontal plane. 

 Snout notably depressed, flat, broad, rounded anteriorl}'^, somewhat 

 ducklike. Hard part of upper jaw with a narrov/ emargination on 

 upper siu"face at symphysis, producing a bilobate effect on a dorsal 

 view, the small space between the lobes more or less bridged with a 

 yellowish, moderately soft tissue. Nostrils small or moderate; one 

 behind the other on a horizontal approximately through upper margin 

 of pupil, at some distance in front of eye; close to each other or rather 

 widely spaced, depending on the genus; anterior one with a slightly 

 raised rim; posterior one with a well raised, somewhat tubular rim, 

 hind part of tubule higher. A lengthwise mucous channel dorsad of 

 the nostrils, opening by two pores of variable size, one at its anterior 

 end not far from upper jaw, the other at some distance from its pos- 

 terior end, near posterior nostril. Mouth rather large, nearly hori- 

 zontal, superior, lower jaw extending beyond upper. Eyes large, inter- 

 orbital narrow. Mandibular rami notably expanded, placed in a 

 ventral position. Maxillary reaching to under posterior margin of 

 pupil or a little behind. Teeth in bands on jaws, vomer, and pala- 

 tines, the band in upper jaw broadening at symphysis; some inner 

 teeth of vomer, of palatines, and at symphysis of upper jaw moderately 

 enlarged in some species. Gill cover having its posterior and greater 

 part thin and flexible, somewhat tapering and prolonged posteriorly, 

 its upper margin horizontal and free for a considerable distance, its 

 lower margin sharply oblique, running upward and backward; with 

 three moderate spinous points, the upper spine close to upper margin, 

 the middle spine moderately spaced, the two forming apical points of 

 two moderate or slight ridges converging forward, the lower spine 

 widely separated, placed at lower margin of gill cover and constituting 

 part of subopercle. Preopercle with one to three spinous points at 

 angle present or absent (subject to individual variability). Gill open- 

 ing wide, branchiostegal membranes overlapping under anterior margin 

 of eye or a little more forward. Gill rakers in moderate numbers or 

 rather numerous. Pseudobranchiae well developed. Scaled nearly 

 all over, including head, chest, fleshy pectoral base, and mandibular 

 rami; snout scaled posteriorly, incompletely scaled to nearly scaleless 

 anteriorly; anterior space between mandibular rami scaleless except 

 in Chriomystax squamentum; pelvic and pectoral fins scaled on a small 



