1903.] NATURAL SCIENCES OF PHILADELPHIA. 731 



{l(ry-^-., slender; Me,a,3pa-, Membras, an old name congeneric with 

 Atherina.) 

 Isclmomeinbras gabunensis sp. nov. Plate XLII (upper figure). 



Head 3|; depth 6; D. VI-I, 9; A. I, 16; P. I, 13?; V. I, 5; scales 

 about 40 (squamation injured), to base of caudal; about 14 before 

 spinous dorsal ; 7 between second dorsal and origin of anal ; width of 

 head 21 in its length; depth of head If ; snout 3f; eye3i; maxillary 3; 

 width of mouth 4|; interorbital space 3^; pectoral U; ventral 2; 

 length of caudal peduncle a little less than head; least depth of caudal 

 peduncle 3^. 



Body rather elongate, compressed, and slender. Sides slightly con- 

 vex. Caudal peduncle elongate, compressed, and its least depth about 

 f its length. 



Head large, elongate, conic, depressed above, compressed laterally 

 and broadly constricted below. Greatest width, also greatest width 

 of body, at postocular region. Side of head more or less flat. Top 

 of head smooth, without conspicuous ridges, and shghtly convex till 

 behind eyes. Snout rather long, pointed, and broadly depressed. 

 Eye rather large, anterior, and close to upper profile. Mouth large, 

 oblique, and mandible slightly protruding. Premaxillaries protractile. 

 Front of upper jaw depressed. Mouth curved in profile. Maxillaries 

 narrow, small, and not reaching opposite front rim of orbit. Mandi- 

 ble expanded anteriorly till as wide as upper jaw, and each ramus 

 elevated rather high inside of mouth. Teeth minute, in narrow bands 

 along edges of each jaw, and none on vomer and palatines. Tongue 

 moderately long, flattened, free in front, and placed rather far back. 

 Nostrils well separated, lateral, anterior circular about half-way in 

 length of snout, and posterior a small slit above eye in front. Inter- 

 orbital space scarcely wider than snout. Postocular ridge distinct. 



Gill-opening large, carried forward below middle of orbit. Rakers 

 short, small, not much more than half of length of filaments and mod- 

 erate. Filaments long. No pseudobranchise. Isthmus narrow and 

 trenchant below, and anteriorly gill-membranes united across for short 

 distance. 



Scales small, thin, cycloid, and somewhat imbricated. Top of head 

 scaled, but scales not extending forward to eye. Opercles scaled, and 

 row of broad scales on cheek. Snout and interorbital space naked, 

 not especially cavernous, and without any ridges. 



Origin of spinous dorsal nearer tip of snout than base of caudal. 

 Dorsal spines weak, somewhat pungent, and when depressed fin reaches 

 f of distance to soft dorsal. Second and third spines longest. Soft 



