Phylum Mollusca Linnaeus, 1758 - molluscs Class Gastropoda Cuvier, 1795 - snails and slugs Subclass Opisthobranchia Milne-Edwards, 1848 - opisthobranchs see Order Opisthobranchia Milne-Edwards, 1848 Order Acochlidioidea Küthe, 1935 [monotypic] see Order Acochlidia Odhner, 1937 1 Superfamily Euacochlidioidea nom. inval.