Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Mollusca Linnaeus, 1758 - molluscs
     Subphylum Diasoma Runnegar & Pojeta Jr., 1974 see Phylum Mollusca Linnaeus, 1758
       Class Scaphopoda Bronn, 1862 - tusk shells
         Order Siphonodentalioida see Order Gadilida Starobogatov, 1974
           Genus Cadulus Philippi, 1844
           Genus Dischides Jeffreys, 1867
           Genus Gadila Gray, 1847
           Genus Polyschides Pilsbry & Sharp, 1898
           Genus Sagamicadulus Sakurai & Shimazu, 1963
           Genus Striocadulus Emerson, 1962