Class Gastropoda Cuvier, 1795 - snails and slugs Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795 Order Mesogastropoda Thiele, 1925 - mesogastropods see [unranked] mesogastropods Superfamily Valvatacea Blake, 1987 see Superfamily Valvatoidea Gray, 1840 1 Family Valvatidae Gray, 1840