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 Muricidae Rafinesque, 1815 - drills
               Subfamily Rapaninae Gray, 1853
                 Genus Cronia Adams & Adams, 1853
                   1 Subgenus Cronia Adams & Adams, 1853
                   2 Subgenus Usilla Adams, 1860
                   3 Subgenus Ergalatax Iredale, 1931 see Genus Ergalatax Iredale, 1931