NATURAL SCIENCES OF PHILADELPHIA. 87 



Body moderately elongated, compressed, quite high and convex at the com- 

 mencement of the dorsal, and thence declining in a slightly arched line to the 

 snout, and under the second dorsal in a straight descending line. Abdominal 

 outline nearly straight. 



Head oblong, rapidly declining downwards, and below nearly straight. 

 Snout subtruncated or convex ; little protuberant. Eyes moderate, entirely 

 anterior. Suborbital region quite high. Preoperculum dentated behind, 

 more coarsely towards the angle, where there are two larger distant radiating 

 teeth. Each ramus of the lower jaw with a small row of minute filaments, and 

 the two lateral pores. A very small median symphyseal pore present. 



Mouth inferior, nearly horizontal. Supramaxillary bones extending to the 

 posterior border of the pupil, and chiefly received under the suborbitars. 



Teeth villiform in both jaws, and with an exterior row of larger ones in the 

 upper. 



Anterior dorsal fin with ten spines. Anal fin with the second spine mode- 

 rate and about half as long as the succeeding ray. 



The variable teeth of the lower and median upper pharyngeal bones elon- 

 gated cylindro-conic. The dentiferous lamina? of the branchial arches com- 

 pressed, and with a row of larger and much curved teeth on their ridges, decreas- 

 ing in size to their free ends. 



Type. Micropogon costatus Dehay. 

 Syn. Boilianus costatus Mit chill. 



Micropogon lineatus Cuv. et Val. 



Genus Pachypops Gill. 



Micropogon sp. Miill. and Troschel, in Schomburgh's Reisen in British Guiana, 

 (pt. iii.) p. 622. 1848. 



Body moderately elongated, highest under the first dorsal, declining towards 

 the snout, and under the second dorsal descending in nearly straight direc- 

 tion. Abdominal outline nearly straight. 



Head oblong, with the snout convex and projecting. Eyes large, longitudi- 

 nally elliptical and with a vertical pupil, partly in the posterior half of the 

 head. Suborbital region of moderate height, much swollen and translucent. 

 Preoperculum finely dentated behind and at its angle. Chin with three bar- 

 bels. Pores small. 



Mouth small, inferior and horizontal. Supramaxillary bones entirely con- 

 cealed iinder the suborbitars. 



Teeth all villiform in a band on each jaw. 



Anterior dorsal fin with ten spines. Anal with its second spine robust, and 

 nearly as long as the succeeding branched ray. 



The variable teeth of the lower and those of the median upper pharyngeal 

 bones are cylindro-conic. The seta? of the first ceratohyals are normal. The 

 dentiferous lamina? of the arches are thick and ridge-like. 



Type. Pachypops trifilis Gill. 



Syn. Micropogon trifilis Miill. and Troschel. 



This species appears to have some affinity to the fish called by Cuvier and 

 Valenciennes Corvina Furcrcea, but that species has apparently no barbels ; 

 they could scarcely have been overlooked if they had been present, for the 

 minute pores of the chin are described. 



Genus Gentonemus Gill. 



Leiostomus sp. Ayres, Proceedings California Academy of Natural Sciences, 

 vol. i p. 25. 1855. 



Body elongated, nearly equally convex above and below, with the dorso- 

 nasal profile nearly straight. 

 Head oblong-conical, with the snout abruptly truncated. Eyes moderate, 



1861.] 



