Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
       Superorder Archaeogastropoda Thiele, 1925
         Order Vetigastropoda Salvini-Plawen, 1980 - archaeogastropods s.l.
           Suborder Neritopsina Cox, 1960 see Order Neritopsina Cox & Knight, 1960
             Superfamily Neritoidea Rafinesque, 1815
               Family Neritidae Rafinesque, 1815 - nerites
                 Subfamily Neritinae Rafinesque, 1815
                   Genus Theodoxus Montfort, 1810
                     1 Subgenus Alinoclithon Baker, 1923
                     2 Subgenus Clithon Montfort, 1810
                     3 Subgenus Neritaea Roth, 1855
                     4 Subgenus Neritoclithon Baker, 1924
                     5 Subgenus Ninnia Westerlund, 1903
                     6 Subgenus Pictoneritina Iredale, 1936
                     7 Subgenus Vittoclithon Baker, 1923