Phylum Mollusca Linnaeus, 1758 - molluscs
   Subphylum Conchifera Gegenbauer, 1878
     Class Gastropoda Cuvier, 1795 - snails and slugs
       Subclass Orthogastropoda Ponder & Lindberg, 1995
         Superorder Caenogastropoda Cox, 1960
           Order Sorbeoconcha Ponder & Lindberg, 1997
             Suborder Hypsogastropoda Ponder & Lindberg, 1997
               Infraorder Littorinimorpha Pchelintsev, 1963
                 Superfamily Tonnoidea Suter, 1913 (1825)
                   Family Cassidae P.A. Latreille, 1825 - helmet snails see Subfamily Cassinae Latreille, 1825
                     1 Subfamily Cassinae Latreille, 1825
                     2 Subfamily Oocorythinae Fischer, 1885
                     3 Subfamily Phaliinae Beu, 1981