Nassarius (Plicarcularia) fissilabris (A. Adams, 1852) 1852. Nassa fissilabris A. Adams, Proc. Zool. Soc. Lond. Pt. 19:99; 1853 Reeve, Conch. Icon. 8: pl.21, fig.138; 1891 E.A.Smith, Proc.Zool. Soc. Lond. p.408; 1934 Mari, J.Conchyl. 78:14. 1901. Nassa (Phrontis) fissilabris (A. Adams), Melvill & Standen, Proc.Zool. Soc. Lond. 2:413. 1930. Nassarius fissilabris (A. Adams), Bisacchi, Ann.Mus.Civ.Stor. Nat. Genova 55:46. Shell up to 18.0 mm in length but frequently smaller, elongate-ovate, some specimens broader than others, teleoconch of 5-5% weakly convex to almost flat-sided whorls, protoconch of 1½ smooth, golden embryonic whorls; sculptured with coarse axial riblets and bisecting spiral grooves which number from 4-7 on the penultimate and from 9-10 on the body whorl apart from 3-4 nodulose spiral cords at base; on the body whorl spiral grooves give rise to flattish cords and the sutural nodules are sometimes bisected by a revolving spiral groove which produces a doubled sutural girdle. Aperture narrow, outer lip thickened and denticulate-lirate, columellar callus expanding and frequently reaching body whorl suture and usually thinning above parietal wall, lower half of columella denticulate, anal canal prominent and continuing almost through to the suture and bordered on left side by a prominent callosity, siphonal notch deep, siphonal fasciole recurved towards aperture. White to straw-yellow in col- our, spire whorls with 2 brown bands which are either continuous or interrupted and forming spots in interspaces, body whorl with a continuous or interrupted central band and another similar band at sutures and base, band frequently visible only as brown spots in interspaces or on the wall of axial ribs, columellar callus porcellaneous white to yellowish with the brownish pattern of the body whorl appearing above parietal wall, aperture white, with 2-3 brown bands deep within, some individuals uniformly pale creamy-yellow. Operculum brown, and serrate at margins.

DISTRIBUTION. Apparently endemic to the Red Sea, Persian Gulf and Gulf of Oman. In coral sand, from the intertidal zone to a depth of 36 m. Type specimens. Three worn syntypes of N. fissilabris (A. Adams), are in the British Museum (N.H.), London, No. 197336, and the specimen measuring length 10.6 mm, width 5.1 mm, is here selected as the lectotype (pl.5, fig.7). Material examined. RED SEA: Dahlak Archipelago, 15°17'N & 40°10'E, 18-36 m (TAU); GULF OF OMAN: Mina Al Fahal, 16 km W. of Muscat (coll.Luther); Masirah I, Sohar, c. 240 km N.W. of Muscat (both coll. Bosch). The type-locality of N. fissilabris is most probably erroneous. E.A. Smith (1891a) reported the species from Aden, Melvill & Standen (1901) from the Persian Gulf and the Mekran coast, and Bisacchi (1930) cites Red Sea localities of Massawa, Dahlak Archipelago, Hawakil I and Assab, and no specimens have been recorded outside the Red Sea Gulf of Oman region. The species is very variable in sculpture, some individuals having a few shallow spiral grooves while others are distinctly spirally striate. The syntypes of N.fissilabris are very worn, but in one syn- type the spiral sculpture is more prominent than in the lectotype.