Calagrassor delicatus n. sp. Holotype NMNZ M.297838 (h 15.8 mm) and 23 paratypes NMNZ M.297837, 1 MNHN, 1 KF-5916, 1 PS-150142. (as listed below). TYPE LOCALITY - New Zealand, South Island, off Jackson Bay, NZS2000 stn 83927, 43°26.80'S, 168°54.20'E, in bored wood, 833-891 m. MATERIAL EXAMINED - New Zealand. South Island, Jackson Bay, NZS2000 stn 83927, 43°26.80'S, 168°54.20'E, in bored wood, 833-891 m.

DESCRIPTION - Shell small, up to 15.8 mm, thin, fragile, semi-transparent, white. Shape oval with short spire and inflated last whorl. Apex eroded, protoconch present but eroded, outer layer of upper spire whorl eroded, transition to teleoconch whorl not visible. Total number of whorls, including protoconch, 5.5, of which first two whorls (protoconch and teleoconch) eroded. First whorl 1.0 mm in diameter; second whorl 1.6 mm in diameter. Third whorl with traces of nine wide, flat spiral cords separated by eight fine grooves. Number of fine spiral grooves gradually increasing; fourth whorl with nine, penultimate whorl with 11 or 12. Last whorl with 33 fine to narrow grooves; ca. 16 on whorl sides, roughly eight slightly wider grooves on base, roughly six on siphonal canal. Axial sculpture absent. Spiral grooves with fine growth lines, giving appearance of minute holes. Aperture semi-ovate. Columella smooth; callus glossy, formed by dissolution of outer shell layer of preceding whorl. Outer lip thin, edge sharp; interior smooth, without lirae or knobs. Aperture plus siphonal canal slightly more than half of total shell height. Periostracum thin, yellowish-brown, smooth, rather glossy, adherent. Operculum thin, corneus, pale brown, semi-transparent, shape oval, nucleus terminal. REMARKS - Calagrassor delicatus n. sp. is characterized by a rather smooth surface with the spiral interspaces reduced to fine grooves. Calagrassor zephyrus shares with C. delicatus n. sp. the thin, semi-transparent shell, rather smooth surface with fine grooves and small adult size, but differs in the presence of fine axial ribs, the slightly shorter spire, the often more irregularly spaced spiral interspaces, the wider aperture, and the shorter siphonal canal. Calagrassor aldermenensis differs from C. delicatus n. sp. in the presence of axial sculpture, the wider spiral interspaces and the rough periostracum. Calagrassor pidginoides n. sp. differs from C. delicatus in the presence of axial sculpture on the upper spire whorls, and the wider spiral interspaces and larger adult size. ETYMOLOGY-Latin delicatus (adjective), refined or delicate, in reference to the fragile, but elegantly shaped shell.