Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
       Order Caenogastropoda Cox, 1960 see Superorder Caenogastropoda Cox, 1960
         Superfamily Rissooidea Gray, 1847
           Family Megalomastomidae Blanford, 1864 see Family Megalomastomatidae Blanford, 1864
             Genus Tomocyclus Crosse & Fischer, 1872