Phylum Porifera Grant, 1836 - sponges Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885 Subclass †Lithistida Schmidt, 1870 Order Megalithistida Reid, 2004 Suborder Megamorina Zittel, 1878 Family Pleromatidae Sollas, 1888 Subfamily †Heterostiniinae Schrammen, 1924