Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
   Order Mesogastropoda Thiele, 1925 - mesogastropods see [unranked] mesogastropods
     1 Family Cyclophoridae Gray, 1847
     2 Family Pomatiasidae Gray, 1852 see Family Pomatiidae Newton, 1891 (1828)
     3 Family Aciculidae Gray, 1850