helmet shell
helmet shell, any marine snail of the family Cassidae (subclass Prosobranchia, class Gastropoda), characterized by a large, thick shell with a shieldlike inner lip. An example is the 18-centimetre (7-inch) king helmet (Cassis tuberosa) of the Caribbean.
Cameos are carved from helmet shells. Smaller, more rounded cassids (Phalium) are called bonnet shells.
Citation Information
Article Title:
helmet shell
Website Name:
Encyclopaedia Britannica
Publisher:
Encyclopaedia Britannica, Inc.
Date Published:
27 June 2017
Access Date:
February 23, 2025