Shell up to 12.0 mm in length but frequently smaller, elongate-ovate to ovate, teleoconch of 3½-4½ convex whorls, early spire whorls angulate at sutures, protoconch of 3%-3% glassy white, finely carinate embryonic whorls; sculptured with slender or moderately broad axial ribs, ribs close-set, usually becom- ing thinner and more numerous towards the outer lip; interspaces very narrow and sculptured with very fine spiral striae, lower third of body whorl with 6-7 rugose spiral cords and a deeper presutural groove forms a row of sutural nodules which are not in any way larger than the axial ribs themselves. 102 Aperture moderately narrow, outer lip variced, denticulate-lirate within, columellar callus partly spreading on to body whorl and frequently thinning above parietal wall, columella with few obsolete denticles. White to cream in colour, usually only sparsely spotted with brown at sutures, but some individuals brightly coloured and ornamented with rhomboidal orange-brown sutural spots, a central line of small spots and a broader, irregular, dilacerated basal band, columellar callus and aperture white. TYPE LOCALITY. Warrior I, Torres Strait, Australia (fretorum); Sorsogon, Albay, Luzon I, Philippines (pusio A.Adams); Balasore Bay, India (ariel).

DISTRIBUTION. From India to the Philippines and N.E. Australia. In sand, subtidal, to a depth of c. 200 m (the specimen from 522 m was devoid of animal). Type specimens. The holotype of N.fretorum (Melvill & Standen) is in the British Museum (N.H.), London, No.1899.2.36.26., length 11.5 mm, width 6.8 mm. Two syntypes of Nassa pusio A.Adams, are in the same Institution, No. 1973130, and the specimen measuring length 7.8 mm, width 4.8 mm, is here selected as the lectotype (pl.15, fig.3). The holotype of N.ariel Preston is in the Zoological Survey of India, No.M-4679/1, length 7.4 mm, width 4.7 mm. Material examined. INDIA: Balasore Bay (ZSI); INDONESIA: S. of Bali 8°46'S & 115°15'E, 19 m; S. of Doe Roa, Moluccas (both ZMC); Sulu Archipelago, 5°43.5'N & 119°40'E, 522 m; Sapeh Strait, 69 m; Madura Bay, 69-91 m (all ZMA); PHILIPPINES: Jolo Sea, 37-55 m; Tubajon Bay, 10°20'N & 125°32'E, 40 m (both ZMC); Punta Engano, Mactan I, Cebu, c. 200 m (coll.Marrow); Balabac I, 124 m (AMS); PAPUA NEW GUINEA: Madang (coll.Bratcher); AUSTRALIA: S. of Fraser I, Queensland (coll. Richter); Black I, Langford reef near Bowen, Queensland, 18 m (AMS).