Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Divasibranchia Minichev & Starobogatov, 1975
       Order Stylommatophora Schmidt, 1855 see Infraorder Stylommatophora Schmidt, 1855
         (Helicid Sigmurethra)
           Superfamily Polygyroidea Pilsbry, 1895 see Superfamily Helicoidea Rafinesque, 1815
             Family Polygyridae Pilsbry, 1895
               Subfamily Polygyrinae Pilsbry, 1895
                 Genus Mesodon Férussac, 1821
                   1 Subgenus Aphalogona Webb, 1954
                   2 Subgenus Appalachina Pilsbry, 1940
                   3 Subgenus Inflectarius Pilsbry, 1940
                   4 Subgenus Patera Albers, 1850, nom. illeg.