Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Opisthobranchia Milne-Edwards, 1848 - opisthobranchs see Order Opisthobranchia Milne-Edwards, 1848
       Order Cephalaspidea Fischer, 1883
         Superfamily Acteonoidea d'Orbigny, 1843
           01 Family Acteonidae d'Orbigny, 1843, nom. protect. - bubble shells
           02 Family Ringiculidae Philippi, 1853
           03 Family Hydatinidae Pilsbry, 1895, nom. illeg. see Family Aplustridae Gray, 1847
           04 Family Bullinidae Gray, 1850 [monotypic]
           05 Family Cylichnidae Adams & Adams, 1854
           06 Family Philinidae Gray, 1850 (1815)
           07 Family Aglajidae Pilsbry, 1895 (1847)
           08 Family Gastropteridae Swainson, 1840
           09 Family Diaphanidae Odhner, 1914 (1857)
           10 Family Notodiaphanidae Thiele, 1931 [monotypic]
           11 Family Bullocardia see Genus Bullocardia Nordsieck, 1972
           12 Family Haminoeidae Pilsbry, 1895
           13 Family Smaragdinellidae Thiele, 1925