Phylum Mollusca Linnaeus, 1758 - molluscs Subphylum Conchifera Gegenbauer, 1878 Class Gastropoda Cuvier, 1795 - snails and slugs Subclass Orthogastropoda Ponder & Lindberg, 1995 Superorder Heterobranchia Burmeister, 1837 Order Opisthobranchia Milne-Edwards, 1848 Suborder Notaspidea Fischer, 1883 Superfamily Pleurobranchoidea Gray, 1827 Family Pleurobranchidae Gray, 1827