Length, 15 mm ; diameter, 6 mm.

Shell small, heavy, up to 15 mm long with high spire. Protoconch high, globose, two whorls, 0.44 mm high, 0.62 mm wide. Teleoconch of 7 whorls, each with up to 11 strong, low axial ribs which tend to line up from one whorl to the next. Suture distinct, slightly undulating. Area below suture flat, ribs begin above midpoint of whorl. Form sharp cusps pointing upwards, extend to lower suture. Penultimate rib of body whorl expanded into a varix, final rib low, outer lip extends beyond rib. Outer lip thickened. Shell surface smooth, glossy with faint axial lirae on surface. Ribs do not extend to tip of body whorl. Instead there are three strong spiral grooves. Aperture elongate, deep, subrectangular. Columella broad, slightly convex. Sinus deep, curved, deeply constricted at opening by callus. Anterior canal short, broad, deep, not notched. Stromboid notch shallow, but distinct. Colour elossv brown tinged with orange in some places; tips of ribs and rostrum white. L= 12.8 , W= 4.8.

Description (based on New Caledonian examples): Narrowly claviform (breadth/length 0.36-0.39), spire occasionally slightly bent; base relatively broad; aperture/total length 0.32-0.34. Anal sinus linguiform to almost lacrimiform, strongly constricted by an angular peripheral nodule, which merges with outer lip; stromboid notch distinct. Axial ribs forming angles (sometimes hooked) at shoulder, somewhat continuous across whorls, opisthocline, in t/s angular, equal to intervals, 8-11 on penultimate whorl, obsolete above shoulder and at parietal level, where there is a row of secondary rib-like nodules; a hump-like terminal varix ca 0.25 whorl behind lip; faint sinuous collabral threads. No spiral sculpture except for 3-5 angular ridges on rostrum, but microscopic collabral striae are present.
Protoconch nearly cylindrical, flat-topped, of two smooth whorls, posteriormost half whorl with fine incremental slightly sinuouse lines. Diameter about 740 µm, height about 600 µm. Protoconch-teleoconch transition distinct, marked by thin but distinct axial riblet in the shape of anal sinus and appearance of strong axial definitive rib.
Glossy, greyish-white with blotches of yellowish or orange, often with an interrupted row of orange-brown spots around middle of last whorl, angles of ribs and base of last whorl white. Measurements (New Caledonian adults): 10.2 x 4.0 mm, 13.9 x 5.0 mm. Radula. Not available.

Shell: high-spired, truncate anteriorly; with broad, blunt axial ribs; white spirally banded with a brown thread. Spire: protoconch not known; teleoconch of fine barely convex whorls; shoulder slope descending broadly, Slightly concave; suture shallow, wide. Sculpture: surface smooth and glossy; axial sculpture of strong, blunt axial ribs, about eight on the last whorl. Aperture: broadly ovate, about one-quarter the length of the spire; outer lip thin at the edge, thickened behind by an axial rib; siphonal canal short, straight. Color: white, broadly banded with brown and with a narrow brown spirai on the periphery of the last whorl.

Only a few, mostly juvenile or damaged shells are available from New Caledonia. These may prove to have a slightly larger protoconch than the types (diameter 0.74-0.87 mm against 0.62-0.67 mm).

Distribution. New Caledonia, Loyalty Islands, Tahiti and Hawaii to southern Japan, Indonesia and Western Australia, littoral to 36 m, under dead coral.

Indopacific and central Pacific. Hawaii.
Type locality
13-18 m depth, Straits of Macassar, New Guinea.
Distribution
Indo-West Pacific; Ashmore Reef, Western Australia to Broadhurst Reef, east of Townsville, Queensland. C. laetus has not previously been recorded from Australia. It is common under dead coral slabs in shallow water. The high spire, brown colour with white tips to the ribs, and white rostrum easily separate C. laetus from other Australian drilliines.