Shell small, bipyramidal, uniformly grey white. Protoconch comparatively large, a small depressed nuclear whorl followed by a larger one, the third whorl with coarse axial threads. Mature whorls four, angular, body whorl long, not restricted at the base. Sculpture of prominent axial ribs, seven to the whorl, persistent from the suture to the base, the summits of the ribs sharp with sloping sides, so that the intercostal spaces are broadly V-shaped, making the cross section of the spire septagonally stellate. The spiral sculpture is strong, of widely spaced cords, overriding the axial ribs and becoming closer on the base and columella. The whole surface between the main spiral cords packed with minute granular spiral threads, only visible under strong magnification. Aperture narrow, tapering anteriorly, the outer margin fortified with a heavy varix with a free thin edge, the sinus shallow, wide and subsutural, its inner margin raised, inner margin straight, angled with the columella and callused within the aperture, columella wedge-shaped, acuminate anteriorly, canal narrow and twisted. Length 4.4 mm., width 1.8 mm., aperture 1.7 mm.

This species is close to two Queensland species, P. bipyramidata Hedley and P. transitans Hedley, but differs from both in its general proportions and details of the sculpture.

Australia. New South Wales. Dredged in North Harbour, Port Jackson.