Galeodea triganceae is a species of large sea snail, a marine gastropod mollusc in the family Cassidae, the helmet snails. Shell description The maximum shell height is 48 mm, and maximum width 31 mm. Distribution This species is endemic to New Zealand including the Chatham Islands. Habitat This helmet shell is found at depths of between 90 and 600 m. References triganceae Gastropods described in 1953