Phylum Porifera Grant, 1836 - sponges Class Hexactinellida Schmidt, 1870 - hexactinellids Subclass Hexasterophora Schulze, 1886 Order Hexactinosa Schrammen, 1903 see Order Hexactinosida Schrammen, 1903 Family Euretidae Zittel, 1877 Subfamily Chonelasmatinae Schrammen, 1912 Genus †Ptychorete Reid, 1964