The specimens in hand are characterized by 1) ovate, moderately high-spired shell up to 30 mm in height, 2) protoconch low-conical, of 3 smooth whorls, the last 2 distinctly shouldered and with a sharp peripheral thread, 3) teleoconch whorls gently convex, with a definite narrow subsutural shelf, 4) strongly nodose subsutural band bounded abapically by a rather wide, shallow groove, 5) sculpture of collabral ribs and spiral grooves in the furrows between ribs; 27 ribs occur on body whorl; some shells exhibit 3 orange-brown bands on the body whorl, respectively adapical, peripheral and abapical. Nassa caelata Adams, 1852, and Nassa verbeeki Martin, 1895, are junior synonyms.
DISTRIBUTION AND HABITAT. Nassarius castus is distributed in the Indo-Pacific, from South Africa to Samoa and northward to Japan. It is a sublittoral element recorded down to 150 m depth, from a variety of coarse- and fine-grained substrates (CERNOHORSKY, 1984).
FOSSIL RECORDS. Late Miocene of Indonesia and Philippines; Pliocene of Indonesia, Philippines, Taiwan, Okinawa and Japan; Quaternary of In-donesia and Japan; Holocene of Thailand.

Shell up to 33.0 mm in length, elongate-ovate, solid, early whorls sub-angulate at sutures, last whorl occasionally inflated, width 46%-62% of length, teleoconch of 6-7% convex whorls, protoconch of 3-3½ glassy, carinate embryonic whorls, sutures very narrowly canaliculate; sculptured with thick or slender axial ribs, ribs numbering from 0-27 on the penultimate and from 0-30 on the body whorl, axial ribs either continue to the outer lip of the body whorl or become obsolete on last 1-3 whorls; spiral sculpture consists of fine spiral striae or grooves which are usually confined to the interspaces and number from 0-5 on the penultimate and from 0-7 on the body whorl, followed by 5-6 spiral cords and an additional 3-6 cords on the siphonal fasciole, spiral sculpture almost obsolete in some individuals, sutural nodules well defined. Aperture moderately wide, outer lip thickened but not strongly varicose, interior with 10-17 lirate denticles, edge of outer lip simple or with a few spinose denticles, columella narrowly calloused and with 5-18 small denticles, siphonal and anal canals distinct. Cream, yellowish-brown, fawn to brown in colour, ornamented with paler, ill-defined spiral bands, dorsal side sometimes with short dark brown bands, columellar callus white, aperture white but occasionally darkening towards interior. Operculum brown, margins simple or serrate or irregularly jagged. TYPE LOCALITY. Pacific Ocean (castus); none (rufum; lactea); Cagayan, Mindanao, Philippines, 46 m (caelata); Burias I, Philippines, 11 m (costata A. Adams); Viti Isles [Fiji Is] (vitiensis); China Seas (elongata Marrat; oriens; sinensis); Levuka, Fiji Is, 22 m (levukensis); Sonde, Java, Pliocene of Indonesia (lectotype of verbeeki); S.Male Atoll, 2-55 m, etc., Maldive Is (maldivensis); Mulaku Atoll, Maldive Is, 2-73 m (mulukuensis); Ras Abu Somer, Red Sea (thaumasia); ? Dar-es-Salaam, East Africa (incognita); Dainiti, Totomi province, Kakegawa series, L.Pliocene of japan (dainitien- sis); Toi Oesapi Soka, Timor, Pliocene of Indonesia (fekuensis); Niki Niki, Timor, Pliocene of Indonesia (fischeri Koperberg); Kii, Japan, 18-37 m (kilensis); Shukubora, Gifu Prefecture, Mizunami group, Miocene of Japan (minoensis); Nihoumatsu, Takanabe machi, Koyu-gun, Miyazaki Prefecture, L.Pliocene of Japan (miyazakiensis). DISTRIBUTION. From the Red Sea and the Persian Gulf to South Africa, Japan and the Samoa Is. In weedy sand, gravel, clay and mud, subtidal to a depth of 150 m. Type specimens. The holotype of N.castus (Gould), is in the National Museum of Natural History, Washington, No.USNM-5724, length 10.4 mm, width 5.3 mm, and the holotype of Buccinum rufum Dunker, is in the Zoological Museum, Humboldt University, Berlin, length 20.5 mm, width 13.0 mm. The following type-specimens are in the British Museum (N.H.), London: three syntypes of Nassa caelata A.Adams, No. 1973122, and the specimen measuring length 16.4 mm, width 9.0 mm, is here selected as the lectotype (pl.24, fig.14); three syntypes of N.costat Adams, No.197327, and the specimen measuring length 14.7 mm, width 8.0 mm, is here designated as the lectotype (pl.24, figs.8,9). Four syntypes of N.levukensis Watson, No.1887.2.9.6.45-8., and the specimen measuring length 17.8 mm, width 9.3 mm, is here designated as the lectotype (pl.24, fig.15); three syntypes of N.maldivensis E.A.Smith, No.1903.9.17.54-56, and the specimen measuring length 25.0 mm, width 14.5 mm, is here designated as the lectotype (pl.25, fig.5); and the holotype of N.mulukuensis E.A.Smith, (no number), length 24.0 mm, width 12.5 mm.