"Shell of moderate size for the genus, subcircular, convex, very thin, translucent white, having faint 'Camptonectes’ divaricating striations, and minute rather distant hollow granule-like scales, which occur on the concentric lines of growth. These scales are usually worn off in the middle of the valves, but remain intact at the sides, where they appear as several radial series. In the holotype, which is 20 mm. in height, the striations are about 8 per mm., and the concentric growth-lines 3 per 2 mm., at the middle of the shell. Hinge-line straight, ears unequal, produced a little longer anteriorly. Sculpture of anterior ear in right valve consists of six rows of imbricating radial ribs which are crossed by the concentric growth-lines. The posterior ear of the right valve and both ears of the left valve are without radial sculpture except for the growth-lines and 'Camptonectes’ striations. Byssal notch deep and wide, with a broad fasciole, and a ctenolium with four free teeth. Apart from the byssal notch the margins are entire, close fitting, thin, and not beveled. The beaks are small, sharply pointed, and approximate. Interior glassy, polished, muscle-scar indistinct. Ligamentary pit very small and shallow. Height 20 mm.; width of valves 19.75 mm.; width of hinge-plate 12 mm.; thickness (two valves) 6 mm." (fide Powell, 1933) Size: Normal adult size range is 15 to 20 mm.

From South Australia, New Zealand, the Tasman Sea, and from the Pacific-Antarctic Ridge.
Habitat: Sublittoral zone to deep water, on muddy bottoms.

Known from the Tasman Sea and off New Zealand in 46-1280 m and from the Pacific-Antarctic Ridge in 914-1152 m.