Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Heterobranchia Burmeister, 1837 [monotypic] see Superorder Heterobranchia Burmeister, 1837
       Order Heterostropha Fischer, 1885
         Superfamily Rissoelloidea Gray, 1850
           Family Omalogyridae Sars, 1878
             1 Genus Omalogyra Jeffreys, 1860
             2 Genus Ammonicera Vayssière, 1893
             3 Genus Retrotortina Chaster, 1896