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
           Family Cylichnidae Adams & Adams, 1854
             Genus Cylichna Lovén, 1846
               1 Subgenus Cylichna Lovén, 1846
               2 Subgenus Acrostemma Cossmann, 1889
               3 Subgenus Clistaxis Cossmann, 1895
               4 Subgenus Cylichnoides Minichev, 1977
               5 Subgenus †Cylichnopsis Cossmann, 1904
               6 Subgenus Eocylichna Kuroda & Habe, 1952
               7 Subgenus Mnestia Adams & Adams, 1854
               8 Subgenus Sphaerocylichna Thiele, 1925