Phylum Porifera Grant, 1836 - sponges Subphylum Hexactinellida Schmidt, 1870 see Class Hexactinellida Schmidt, 1870 Class Hexasterophora F.E. von Schulze see Subclass Hexasterophora Schulze, 1886 Order Hexactinosida Schrammen, 1903 Family Tretodictyidae Schulze, 1886 Genus Sclerothamnopsis Wilson, 1904