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 Heterostropha Fischer, 1885 Superfamily Omalogyroidea Sars, 1878 Family Omalogyridae Sars, 1878