Phylum [Mollusca] Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
       Order Archaegastropoda see Order Archaeogastropoda Thiele, 1925
         Superfamily Neritacea see Superfamily Neritoidea Rafinesque, 1815
           Family Neritidae Rafinesque, 1815 - nerites
             Subfamily Neritinae Rafinesque, 1815
               Genus Theodoxus Montfort, 1810
                 Subgenus Theodoxus (Clithon) Montfort, 1810