[Class] Polycystinea Ehrenberg, 1838 - polycystines see Superclass Polycystinia Ehrenberg, 1838
   Order Spumellaria Ehrenberg, 1875 see Class Spumellaria Ehrenberg, 1875
     Family Actinommidae Haeckel, 1862
       Genus Hexacromyum Haeckel, 1881
         1 Hexacromyum elegans Haeckel, 1887
         2 †Hexacromyum rara (Carnevale, 1908)