An Unusual Lamellariid Gastropod from Bathyal Depths in the Sea of Japan

Abstract

A large-sized lamellariid, Onchidiopsis nihonkaiensis n. sp. collected from deep waters in Ryotsu Cove, Sado Island, the Sea of Japan is described. This species is characterized in having an oval gelatinous body spotted by white on black dorsal mantle in which a large, shallow, transparent, oblong oval shell with rudimentary spire. This is the second species of this genus hitherto known from Japanese fauna.