Bilateria Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
   Spiralia Schleip, 1929 - spiralians see Superphylum Spiralia Schleip, 1929
     Platyzoa Ax, 1987 see [unranked] Spiralia Schleip, 1929
       Gnathifera Ahlrichs, 1995
         Phylum Gnathostomulida Ax, 1956 - gnathostomulids
           1 Class Bursovaginoidea see Order Bursovaginoidea Sterrer, 1972
           2 Class Filispermoidea see Order Filospermoidea Sterrer, 1972