Kingdom Animalia Linnaeus, 1758 - animals Phylum Mollusca Linnaeus, 1758 - molluscs Subphylum Cyrtosoma Runnegar & Pojeta Jr., 1974 see Phylum Mollusca Linnaeus, 1758 Class Gastropoda Cuvier, 1795 - snails and slugs Subclass Opisthobranchia Milne-Edwards, 1848 - opisthobranchs see Order Opisthobranchia Milne-Edwards, 1848 Genus †Bactroptyxis Cossmann, 1896