About Semicassis pyrum (Lamarck, 1822)
Semicassis pyrum, with the common names "pear bonnet" or "common helmet", is a species of large sea snail. It is a marine gastropod mollusc that belongs to the family Cassidae, a group that includes helmet shells, bonnet shells, and their close relatives. Its accepted scientific name is Semicassis pyrum (Lamarck, 1822).