Shell globosely conic, turbinate, spirally ribbed and obliquely longitudinally striated ; aperture nearly circular, umbilicated ; outer lip thickened internally and ribbed. Colour light green, spotted with darker, spots arranged longitudinally and obliquely.

Remarks. The main characteristics of this species are:
♦ height about 3.8 mm, width about 3.7 mm (lectotype);
♦ moderately elevated spire, conical to slightly cyrtoconoidal; sculpture cancellate;
♦ protoconch smooth;
♦ teleoconch of about 4 slightly convex whorls with 5 granular spiral cords on penultimate whorl; subangular periphery; P1, P2 and P3 clearly visible at 2nd whorl, P3 the strongest; axial threads between cords, connecting rounded beads of cords; distance between cords similar to cords; on 3rd whorl, S1 resolving with S2 possibly later; P4 peripheral on last whorl, possible S3, thinner;
♦ columella with a weak basal tooth;
♦ moderately convex base with 3 rather thick, granular, spiral cords; distance between cords larger than cords; axial threads between cords;
♦ labral folds all around the outer lip of the aperture;
♦ narrow deep umbilicus;
♦ whitish with dark spots.

Euchelus corrugatus Pease, 1861. Length, 4 mm; diameter, 4 mm. Shell: trochiform; with granular spirals; cream with flashes of dark red. Spire: five whorls; suture grooved. Sculpture: granular keels separated by interspaces equal in diameter to the keels, and axially joined by obliquely set lamellae of lesser diameter. Aperture: subcircular; iridescent and lirate within; outer lip thick; columella straight, toothed at the base; base convex, umbilicus of variable depth; base with obsolete spiral granules; operculum circular, horny, multispiral with a central nucleus. Color: white or cream with flamelike markings of ashy rose. Animal: exposed parts yellow except for the cephalic tentacles, which are outlined in black. E. corrugatus is a commonly occurring trochid in the leeward islands and on Kauai, but is rare along the shorelines of Oahu, Maui, and Hawaii. On Kauai it is found on rocks and rubble in tide pools and on benches.
This species was described from the Hawaiian Islands and also occurs along the coastline of southern India, and at Bikini in the Marshall Islands.

Differences with H. fimbriatum (Pease, 1861) (type locality: Sandwich Island, nowadays Hawaii) seem not obvious. Kay (1965) mentions the lack of umbilicus and, apparently ("four cords on last whorl" ?) the presence of the single S1. Severns (2011)
figures the NHMUK holotype, unfortunately without a basal view; only SI is visible as secondary cord. Herbert (2012) also figures the holotype and mentions a more angular periphery and three spiral cords on the penultimate whorl (instead of how many for H. corrugatum ?). Moreover, Kay (1979) points out that there are no recent records of this species in Hawaii area. Further studies are clearly needed to establish the specific features of this poorly known species. All the samples from French Polynesia here examined have an umbilicus and are considered as H. corrugatum, although some of them have an earlier S1 and a more elevated spire .

Distribution. Hawaii, Marshall Islands, subtidal (Kay, 1979; Severn, 2011); French Polynesia, Marquesas Islands, l-60m, lv at 60-61 m.