PROC. BIOL. SOC. WASH. 92(3), 1979, pp. 580-588 STENOCOROPHIUM BOWMANI, A NEW GENUS AND SPECIES OF THE FAMILY COROPHIIDAE FROM THE PALAU ISLANDS (CRUSTACEA: AMPHIPODA) Gordan S. Karaman^ Abstract. — A new genus and species of the family Corophiidae, Steno-corophium bowmani is described from Babelthuap Island (Palau Islands in southern Pacific, E. of Philippines). This genus is closely related to the genus Paracorophium Stebbing 1899, but differs in the simple 6 gnathopod 2 and the uniramous uropod 3. Thanks to Dr. Thomas E. Bowman and Dr. J. Laurens Barnard from the Smithsonian Institution, Washington, D.C., I was able to study an amphipod from the bottom of the Ngermeskang River, above tidal influence, on Ba-belthuap Island (Palau Islands in the South Pacific). The specimen proved to represent a new genus and species of the family Corophiidae, described below. Stenocorophium, new genus Diagnosis. — Body smooth, Paracorophium-likc, urosomites 1-2 co-alesced, urosomite 3 free. Antennae normal; accessory flagellum absent. Labrum incised symmetrically; labium with long inner lobes. Maxilla 1: inner lobe short, outer lobe with ca. 7 spines, palp 2-articulate. Maxilla 2: both lobes moderately narrow, inner lobe without dorsal oblique row of setae. Maxilliped: outer lobe with a row of slender spines along inferior margin; palp 4-articulate, palp article 2 elongated, palp article 3 not lobed. Mandible: incisor toothed, molar triturative, palp 3-articulate. Coxa 1 produced at ventroanterior part, coxa 4 without distoposterior lobe, coxa 5 long. Gnath-opod 1 subchelate. Gnathopod 2 simple, but its article 4 elongated and article 5 attached proximally on article 4, like that in genus Paracorophium. Article 2 of pereopods 6-7 lobed, pereopod 7 extremely enlarged. Uropods 1-2 well developed; peduncle of uropod 1 with ventrodistal long tooth like that in genus Paracorophium. Uropod 3 short; inner ramus absent; outer ramus uniarticulate, as long as peduncle. Telson fleshy, short, entire, with distal corner tooth on each side in lateral view. Coxal gills ovoid, normal. Type-species. — Stenocorophium bowmani, n. sp. Contribution to the knowledge of the Amphipoda 99.