Nassarius (Niotha) delicatus (A.Adams, 1852) (Plate 14, figs.4-8) 1852. Nassa delicata A.Adams, Proc.Zool. Soc. Lond. Pt. 19:99; 1854 Reeve, Conch. Icon. 8:pl.27, figs. 180a,b; 1876 E.A.Smith, J.Linn.Soc. Lond. 12:546; 1877 Brazier, Proc. Linn.Soc.N.S. W. 1:178; 1887 v.Martens, J.Linn. Soc. Lond. 21:182; 1934 Mari, J.Conchyl. 78:13. 1852. Nassa nodicostata A.Adams, Proc. Zool. Soc. Lond. Pt.19:99; 1853 Reeve, Conch. Icon. 8:pl. 15, figs.97a,b; 1885 Cooke, Ann. Mag. Nat. Hist. (5), 15:327; 1934 Mari, J.Conchyl. 78:14. 1904. Nassa (Phrontis) tiarula (Kiener), Sturany, Denk.k.Akad. Wiss.math.-nat. Wien 74:243 (non Buccinum tlarula Kiener, 1841 Nassarius). 1911. Nassa (Phrontis) delicata A.Adams, Schepman, Siboga-Exped. 49d:322. 1918. Alectryon (Phrontis) alcimus Melvill, Ann. Mag.Nat. Hist. (9), 1:139, pl.4,fig.2. 1930. Nassarius delicatus (A.Adams), Bisacchi, Ann. Mus Civ.Stor.Nat.Genova 55:45. 1930. Phrontis nodicostata (A.Adams), Bisacchi, Ann. Mus.Civ.Stor. Nat.Genova 55:65. 1978. Nassarius (Niotha) delicatus (A.Adams), Cernohorsky, Trop. Pacific mar.shells p.83, pl.25, fig.7. Shell up to 15.0 mm in length but frequently smaller, teleoconch of 3½-4½ convex whorls, pro- toconch of 3%-3% finely carinate, milky embryonic whorls; sculptured with strong rounded axial ribs, ribs on last whorl either thick or slender, smooth or nodulose; spiral sculpture consists of fine spiral striae which often become obsolete, a presutural groove which separates sutural nodules from axial ribs, base of shell with 4-6 granulose, wavy spiral cords. In some individuals the sutural nodules on the body whorl can be moderately echinate and nodules on axial ribs quite distinct. Aperture nar- row, outer lip thick and variced, denticulate-lirate within, columellar callus partly expanding on to body whorl and usually broader above parietal wall, columella denticulate, siphonal and anal canals distinct. White in colour, some individuals marbled or faintly banded with brown, remnants of a band usually visible on the varix, many specimens stained purple-brown on the dorsal side of the siphonal canal, occasional specimens with an interrupted brown peripheral line on body whorl, columellar callus and aperture white. Operculum brown and serrate at margins. TYPE LOCALITY. Albay, Luzon, Philippines, 11 m (delicata); Corregidor I, Philippines, 11 m (nodicostata); Mekran coast, Persian Gulf (alcimus). DISTRIBUTION. From the Red Sea and the Persian Gulf to the Ryukyu and Fiji Is. In clean and weedy coral sand, rarely intertidal, usually from 2-403 m. Type specimens. The following types are in the British Museum (N.H.), London: four syntypes of N.delicatus (A.Adams), No. 197332, and the syntype measuring length 9.8 mm, width 6.0 mm, is here selected as the lectotype (pl.14,fig.4); the holotype of Nassa nodicostata A.Adams, No.1973127, length 13.6 mm, width 8.3 mm, and the holotype of Alectryon alcimus Melvill, No., 1921.1.28.2, length 15.0 mm, width 8.8 mm.

Material examined. RED SEA: Dahlak Archipelago, 15°17'N & 40°10'E, 18-36 m; El Hamira Bay, 2-4 m; off Gzeirat, 50 m; off Mersat Abu Samra, 51-53 m; off Nuweiba, 329-403 m; Masra el Et, Gulf of Aqaba; Sharm el Maya, Gulf of Aqaba (all TAU); Gulf of Suez (USNM); Eilat, Gulf of Aqaba (TAU; USNM); S.side of Dissel 1, 25 km off Massena, 4-5 m (AMS); 5-8 km S. of Aqaba (coll. Mastaller); PERSIAN GULF: Mekran coast (BMNH); MADAGASCAR: Tulear (SMOM); MAURITIUS: (AMS); INDONESIA: Bali Sea, 7°15'S & 115°15.6'E, 289 m; reef near Batjulmati, Java, 15 m; Lumu Lumu shoal, Borneo Bank, 34 m; Banda, 9-45 m; Bay of Pidjot, Lombok, 22 m; Sulu Harbour, Sulu 1, 14 m; Tual Kai Is, 22 m; Kwandang Bay entrance, 75 m (all ZMA); N.of du Rowa, N. of Nuhu Rowa, Kai Is, 33-37 m; off Tg Tutuhuhur, Piru Bay, Ceram, 26-48 m (both WAM); Tamandjaijai, Bantam, Java (USNM); PHILIPPINES: off Tinakta I, Tawi Tawi group, 18. m; off Bakun, Tawi Tawi (both USNM); RYUKYU IS: Bolo Pt., Okinawa (coll.Deynzer); PAPUA NEW GUINEA: Luai 1, Trobriand group (AMS); Escape Bay, Rabaul, New Britain (coll. Parkinson); NEW HEBRIDES: Malapoa Pt., Efate I (coll. Bratcher); LOYALTY IS: Ouvea I (coll.Coles); Lifu I (coll.Boust); FIJI IS: Main reef, Suva, S.Viti Levu (coll.Northgrove); Lakeba I, Lau group (AIM). Melvill (1918) suspected that his Nassarius alcimus may be only a local variant of Nassa nodicostata Adams, but the form alcimus is closer to the typical form of delicatus and is the prevalent form in the Red Sea and the Persian Gulf region. The more nodulose form nodicostata occurs more frequent- ly towards the Eastern Indian Ocean and Western Pacific. The species does not appear to be separable from N.delicatus (A.Adams). Nassarius persicus Cox, 1936, in addition to being a probable synonym, is also a secondary homonym of Nassa persica v.Martens, 1874, which is a valid species known in the combination Nassarius (Plicarcularia) persicus (v.Martens).