Semicassis pyrum

Semicassis pyrum, common name the "pear bonnet" or "common helmet", is a species of large sea snail, a marine gastropod mollusc in the family Cassidae, the helmet shells, bonnet shells and their allies.

A shell of Semicassis pyrum, ventral view showing the parietal callus

Semicassis pyrum
A shell of Semicassis pyrum, lateral view
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Family:	Cassidae
Genus:	Semicassis
Species:	S. pyrum
Binomial name
Semicassis pyrum (Lamarck,1822)