Shell small, conical, thin, semitransparent, yellowish, with a peripheral series of brown spots. Whorls 4,5, slightly convex; protoconch 1,5 whorls, dome-shaped, very slightly tilted, apex brown, rest white, very finely spirally striate; body whorl moderately globose, periphery and base rounded. Aperture ovate, angled, channelled anteriorly and posteriorly; columella vertical, thin, separated from base in lower portion, a chink but no umbilicus behind; inner lip thin; outer lip slightly thickened, no obvious varix. Sculpture of fine axial riblets, weak to moderately strong on body whorl, very weak on spire whorls; fine spiral lines over the whole surface, two to five moderately strong spiral cords on periphery (three in holotype), suture margined by a weak spiral cord. Colour yellowish-white, a colourless band in middle of whorls, lower part of base and aperture white, except for a brown blotch on lower part of columella. A row of irregular brown spots below periphery on last half of penultimate and body whorl, a row of pure white spots on a colourless band on body whorl, and a yellowish-brown band on periphery may break up into large irregular blotches on last half of body whorl.
Though similar to R. (H.) infecta (Suter), the new species is readily distinguished by its colour pattern, somewhat smaller size and weak axial sculpture.
Animal and operculum very similar to R. (H.) hamiltoni (Suter) but foot and snout have less black coloration
MATERIAL EXAMINED
Holotype: Bream Tail, Corallina, 21/8/63, W.F.P. (Auckland Museum). Height 1.59mm, width 0.92mm.
Paratypes: Auckland, Dominion and Canterbury Museums and the New Zealand Geological Survey, Lower Hutt.