Linné, 1758
Description (shell):
Shell conical with irregular radiating costae. Apex central or slightly anterior; apical angle variable, smaller (70-80°) in high shore specimens, larger (105-115°) in low shore and young animals (P. vulgata-drawing).
Size:
Up to 60 x 50 x 30 mm.
Colour:
White or grey externally. Inner surfaces grey-green.
Animal:
Distinct head with mouth, paired tentacles and eyes. Mantle skirt fringed with translucent pallial tentacles arranged in three series of different lengths, internal to which lies a complete circlet of pallial gills (P. vulgata-animal).
Habitat:
From between MHWST-MHWNT downward to ELWST on all suitable rocky shores; upper limit of distribution increased by shade and exposure (P. vulgata-photo). Tolerant of low salinity but generally confined to habitats with salinity >25 ä.
Distribution:
Distributed from Mediterranean to Lofoten Islands, Norway (Distr. P. vulgata). Also reported off Helgoland by K. Janke (Harms, 1993).