Shell large and deep, with dense, fine, flattened ribs, which project only slightly at the margin; surface almost always eroded and encrusted. Dark brown or blackish, often with concentric zones; interior white with a brownish centre. Maximum length 104 mm.

Inhabits exposed rocks in a belt at about low-water spring-tide level, especially where these are encrusted with calcareous algae (Lithothamnion). Juveniles often cling to the shells of the adults. This limpet forms a deep home-scar which it vacates, when washed by the incoming tide, to graze on Lithothamnion and diatoms, although seldom straying further than 60 cm. When wetted by moving water, P. argenvillei raises its shell slightly away from the surface, and is thus relatively easy to dislodge. It spawns in winter.

Namibia to western Transkei (South-Africa).