Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Scaphopoda Bronn, 1862 - tusk shells
     Order Gadilida Starobogatov, 1974
       1 Family Entalinidae Chistikov, 1979
       2 Family Pulsellidae Boss, 1982
       3 Family Siphonodentaliidae Tryon, 1884 see Subfamily Siphonodentaliinae Tryon, 1884
       4 Family Gadilidae Stoliczka, 1868
       5 Family Wemersoniellidae Scarabino, 1986 [monotypic]