Nassarius foveolatus is characterized by 1) elongate-ovate shell up to 22 mm in height, 2) proto-conch low-conical and small, of 3 smooth whorls, the last finely carinate, 3) teleoconch whorls gently convex, meeting at fine, adpressed sutures, 4) body whorl about 75% of the total height, gradually tapering at the base, 5) siphonal fasciole wide, with 5-7 flat spirals, 6) outer lip swollen, with a denticulate edge and with 12 short ribs on its inner side, 7) inner lip thinly callused, with a parietal ridge and a row of 7-10 bluntly rounded tubercles, 8) sculpture weak, consisting of collabral folds and spiral ribbons in the furrows between folds; 29-35 folds and 23-28 spirals, the most abapical somewhat stronger, occur on body whorl. Nassarius foveolatus differs from Nassarius concinnus (Powys, 1835), the most closely related species, in that it has a slenderer shell, subsutural denticles on earliest teleoconch whorls only and otherwise missing, and more numerous spirals. The present specimens exhibit a concinnus-like color pattern, i.e., 3 brown spiral bands on body whorl.
DISTRIBUTION AND HABITAT. The species ranges from Pakistan to Malaysia, occurring intertidally on mud flats and among mangroves (CERNOHORSKY, 1984). Previous records in western Thai waters were from mud flats seaward of mangrove forest (TANTANASIRIWONGANA, 1978).
FOSSIL RECORDS. Holocene of Thailand.

Nassarius (Zeuxis) foveolatus (Dunker, 1847) Shell up to 22.0 mm in length, slender, elongate-ovate, teleoconch of 5%-6½ convex whorls, protoconch missing in specimens examined, sutures tight; sculptured with numerous, fine axial ribs. which frequently become irregular and weak on the body whorl and number from 26-42 on the penultimate and from 25-33 on the body whorl; spiral sculpture consists of numerous fine spiral striae which are confined to the interspaces of axial ribs and number from 7-13 on the penultimate and from 18-21 on the body whorl apart from 5-7 stronger, granulose cords at base, spiral striae continue on to the back of the outer lip, siphonal fasciole with 6-7 cords, spire whorls with sutural nodules. Aperture narrow, elongate, outer lip thickened and with a prominent varix, interior with 8-12 den- ticles, columella narrowly calloused and with 7-11 almost geometrically placed rounded denticles, siphonal notch distinct, anal canal prominent. Leaden-grey to purplish-grey in colour, sutures and varix paler creamy-white, columella grey to violet, edge of aperture white, interior dark grey. TYPE LOCALITY.Oriental India (foveolatus); Payta, Peru error! (planocostata); none (labida). DISTRIBUTION. From Pakistan to Malaysia. On mudflats and among mangroves, within the inter- tidal zone. Type specimens. Syntypes of N.foveolatus (Dunker), are in the Zoological Museum, Humboldt University, Berlin, and the specimen measuring length 17.2 mm, is here selected as the lectotype (pl. 29, fig. 12). Three syntypes of Nassa planocostata A.Adams, are in the British Museum (N.H.), London, No. 1973153, and the syntype measuring length 17.0 mm, width 8.1 mm, is here selected as the lec- totype (pl.29, fig.13). The type of Nassa labida Reeve, is lost. Material examined. PAKISTAN: Karachi (USNM); INDIA: Madras (ZSI); THAILAND: Ko Maphrao, Phuket (PMBC); MALAYSIA: Batu Ferringhi, Penang (coll.McCausland); Singapore (coll.Johnson). The taxon N.planocostata (A.Adams), has erroneously been reported from the west coast of South America, and this writer (Cernohorsky 1975a) has shown that the Peruvian locality is erroneous and that the species lives in the Indian Ocean.

Synonymy with N. planocostata. Three syntypes in B.M.N.H.; illustrated syntype 17.0x8.1 x 9.0 mm. Lead-grey in colour, spire whorls with a brownish sutural band, penultimate whorl with 32 axial ribs and body whorl with 31, very closely spirally striate, interstices of ribs appearing pitted, base of body whorl with 12 spiral cords, columella finely denticulate along its entire length, outer lip with 12 denticles. Payta, Peru |= Paita, Peru, = error).

The species has been erroneously reported from Peru and has been accepted as of Peruvian origin by all subsequent American authors. Tomlin (1932) cast some doubt on the species South American origin when he correctly synonymiscd Nassa foveolata Reeve with Buccinum fovealatum Dunker, commented on the dose similarity of Nassa planocostata A. Adams to Buccinum foveolatum and considered the type-figure of Nassa labida to possibly represent N. planocostata. The syntypes of N. planocostata which are accompanied by a MS label "Karachi -Townsend", are undoubtedly conspecific with Nassarius foveolatus (Dunker) from the Indian Ocean. Recent examination of specimens of N. foveolatus from Madras, India (Zool. Survey India) enabled the writer to select a specimen which closely corresponds to Adams' syntype of N. planocostatus.