Cassidae: Semicassis (Semicassis) thomsoni (Brazier, 1875) (‘Thomson’s helmet’)
Synonym(s): thomsoni Brazier, 1875 palinodia Iredale, 1931.
Typical shell-length 80 mm. Lives subtidally and offshore on sand. Native. Occurs in eastern Australia (QLD, NSW, TAS and VIC); also New Zealand.
Classification
Class: Gastropoda
Subclass: Caenogastropoda – Sorbeoconcha
Order: Hypsogastropoda – Littorinimorpha
Superfamily: Tonnoidea
Family: Cassidae
Subfamily: Cassinae
Genus: Semicassis
