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 Genus †Hexactinella Carter, 1885 Subgenus †H. (Hexactinella) Carter, 1885