Shell up to 35.0 mm in length,fusiform - elongate, teleoconch of 9-10 slightly subangulate whorls, protoconch unknown. Post-embryonic whorls with 4 granulose spiral cords, interspaces pitted, penultimate whorl with 8-11 spiral rows of beads and body whorl with 24-30 rows, siphonal fasciole with 6-7 oblique cords; the beads are produced by moderately close-set longitudinal grooves and at the sutures 2-4 rows of beads are usually smaller, laterally elongated and compressed. The spiral rows of beads are irregular in size and some rows are considerably smaller. Aperture shorter than the spire, smooth within, columella almost without a callus and with 4-5 folds, siphonal canal straight. There is no definite ornamentation but orange-brown zones and streaks alternate with white ones and occasionally the body whorl has an irregular, broad, orange-brown central band, aperture flesh to pale orange-brown.

This is a moderately wide mitrid (W/L = 0.27 to 0.33 for illustrated specimens) with the spire slightly longer than the aperture (S/L = 0.52 to 0.57 for illustrated specimens). The spire sides are slightly convex with 7 to 10 convex teleoconch whorls in illustrated specimens. The suture and dorsal notches are promi¬nent. The fasciole bulges convexly. Sculpture on the type illustration has about 16 convex spiral cords on the penultimate whorl crossed by convex axial riblets or about equal diameter forming rounded nodes at the intersections. Sometimes the spiral cords are fewer on the penultimate whorl (about 12) and sometimes much more variable in diameter. The outer lip is slightly convex becoming more convex at the transition into the anterior canal. There are 3 significant spiral folds on the columella. The exterior shell color is brown with white spots forming wide axial streaks. The aperture is lighter brown.

The species appears to be endemic to the Marquesas Islands but is rarely found. N. arenacea closely resembles the W. African N. hebes (Reeve).

Range - Central Pacific. Marquesas Islands.