Phylum Porifera Grant, 1836 - sponges Class Hexactinellida Schmidt, 1870 - hexactinellids Subclass Hexasterophora Schulze, 1886 Order Hexactinosa Schrammen, 1903 see Order Hexactinosida Schrammen, 1903 Family Euryplegmatidae de Laubenfels, 1955 [monotypic] see Family Aulocalycidae Ijima, 1927 Genus †Euryplegma Schulze, 1886