Phylum Porifera Grant, 1836 - sponges
   Class Hexactinellida Schmidt, 1870 - hexactinellids
     Subclass Hexasterophora Schulze, 1886
       Order Hexactinosa Schrammen, 1903 see Order Hexactinosida Schrammen, 1903
         Family Tretodictyidae Schulze, 1886
           Subfamily Tretodictyinae Schulze, 1886
             1 Genus †Psilocalyx Ijima, 1927
             2 ?Genus †Prohexactinella Moret, 1926
             3 Genus †Hexactinella Carter, 1885
             4 Genus †Tretodictyum Schulze, 1886
             5 Genus †Auloplax Schulze, 1904
             6 Genus †Ramalmerina Brimaud & Vachard, 1987
             7 Genus †Sclerothamnopsis Wilson, 1904