Gastropoda Cuvier, 1795 see Class Gastropoda Cuvier, 1795 Cephalaspidea Fischer, 1883 see Order Cephalaspidea Fischer, 1883 Retusoidea Thiele, 1926 see Superfamily Philinoidea Gray, 1850 (1815) Family Retusidae Thiele, 1925 Genus Retusa Brown, 1827 1 Retusa truncatula (Bruguière, 1792)