Phylum Mollusca Linnaeus, 1758 - molluscs
   Conchifera Gegenbaur, 1878 see Subphylum Conchifera Gegenbauer, 1878
     Cyrtosoma
       Class Gastropoda Cuvier, 1795 - snails and slugs
         1 Subclass †Archaeobranchia Parkhaev, 2001
         2.1 Subclass †Divasibranchia Minichev & Starobogatov, 1975
         2.2 Subclass †Dextrobranchia Minichev & Starobogatov, 1979
         3 Eogastropoda Ponder & Lindberg, 1995 see Subclass Eogastropoda Ponder & Lindberg, 1995
         4 Orthogastropoda Ponder & Lindberg, 1995 see Subclass Orthogastropoda Ponder & Lindberg, 1995