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 Sacoglossa Ihering, 1876 - sacoglossans Suborder Tamanovalvina Superfamily Julioidea see Superfamily Oxynooidea Stoliczka, 1868 (1847) Family Costasiellidae Clark, 1984 [monotypic] see Family Limapontiidae Gray, 1847 1 Genus Costasiella Pruvot-Fol, 1951