[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Mollusca Linnaeus, 1758 - molluscs
         Branch Eucephala
           Grade Echinoglossa
             Class Gastropoda Cuvier, 1795 - snails and slugs
               Grade Cochlides
                 Order Natantia Lankester, 1877
                   1 Genus Atlanta Lesueur, 1817
                   2 Genus Pterotrachea Forskål, 1775