Shell large, broad-fusiform, with strongly convex whorls. Siphonal canal distinctly attenuated, narrow. Aperture broad oval. Spiral sculpture of inconspicuous narrow ribs, abraded on most part of shell surface. Axial sculpture of S-shaped low folds, up to 16 on last whorl. Periostracum pale-yellow. Measurements: no. 1. H 82.6 mm, h 53.5 mm, AL 38 mm.
Soft body. Mantle spans one whorl, kidney 0.3, digestive gland and gonad - rest of visceral mass. Head wide, with thick, contracted tentacles and small black eyes situated on tentacles lobes. Foot folded transversely, with narrow propodium, separated by deep propodial groove. Operculum oval, with terminal nucleus. Mantle length exceeds width. Siphon moderately long, siphonal valve (sv) well developed. Osphradium small, slightly asymmetrical, spans 0.3 mantle length and three times narrower than ctenidium. Ctenidium 0.8 mantle length. Rectum on inner side of strongly developed capsule gland and opens at middle of mantle. Hypobranchial gland forms numerous folds. Pallial oviduct of large two-lobed capsule gland and vagina. Vagina with thick walls, situated ventrally of capsule gland.

The species is very similar to P kroeyeri, differing in less pronounced axial ribs. It may be a junior synonym of P. kroeyeri. In the absence of additional material we prefer to consider it a separate species.

Sea of Okhotsk. Russia, Japan (Hokkaido). Type locality - off Monbetsu, northern Hokkaido.