Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Divasibranchia Minichev & Starobogatov, 1975
       Order Basommatophora Keferstein, 1865 see Suborder Basommatophora Keferstein, in Bronn, 1864
         Superfamily Planorbioidea Vaught, 1989, orth. inval. see Superfamily Planorboidea Rafinesque, 1815
           Family Ancylidae Rafinesque, 1815 - freshwater limpets see Tribe Ancylini Rafinesque, 1815
             Subfamily Ferrissiinae Walker, 1917 see Tribe Miratestini Sarasin & Sarasin, 1897
               Genus Ferrissia Walker, 1903
                 Subgenus Watsonula Mirolli, 1960