Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
       Order Neogastropoda Wenz, 1938 see Suborder Neogastropoda Wenz, 1938
         Suborder Stenoglossa Bouvier, 1887
           Superfamily Muricoidea Rafinesque, 1815
             Family Cystiscidae Stimpson, 1865
               Subfamily Cystiscinae Stimpson, 1865
                 1 Genus Topaginella Laseron, 1957
                 2 Genus Cystiscus Stimpson, 1865
                 3 Genus Crithe Gould, 1860
                 4 Genus Extra Jousseaume, 1894