Northern Norway to Sénégal, Madeira to Mediterranean, at least in its western part. There is also a spot in the Virgin Islands (fossil), which may indicate an ancient amphiatlantic distribution. Predator on sessile preys in the circalittoral, the continental shelf and the upper slope. Synonyms: anassa, crassalta (for high-domed specimens), decussata, gigantea for some fossils, and magnifica. This is the largest Emarginula of the european waters. Above, the species in J. Sowerby: The mineral conchology of Great Britain, vol. I, London 1813, plate XXXIII. The shell of fully adult specimens is remarkably thick, hence its name. It is also decussate and very large.