Shell elongate, fusiform of seven whorls excluding the protoconch of two smooth glassy, slightly pulliform whorls; spire whorls trapezoidal, with a sharp central keel, concave above, slightly convex below where they are embraced by the suture; the keel has plicate tubercles from which long, basal axial costae extend, gradually fading out at the sutures, eleven in the body and penultimate whorl; axials crossed by spiral lirae equidistant except over the base where they become more oblique and distant; aperture elongate oval, outer lip crenulate throughout, numerous close spiral striae within; columella smooth, three oblique plaits; periostracum thin, greyish; aperture and shell white.
Length 143 mm, width 55 mm.
Locality: West Aust., 60 miles west of Eucla, 72 fms. (type).
A half-grown specimen 80 mm. x 35 mm. is typical but has a comparatively larger almost bulbous protoconch, but it is undoubtedly the same species, A third specimen, a juvenile, is 33 mm. in length and shows the typical features. The species is readily separated from P. australasia coronata in being more elongate, keeled, white in colour and of more delicate structure, The holotype was mentioned as a variant of Fasciolaria australasia by Verco 1912.