Phylum Porifera Grant, 1836 - sponges Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885 Subclass †Lithistida Schmidt, 1870 Order Tetralithistida Lagneau-Hérenger, 1962 1 Suborder Tetracladina Zittel, 1878 2 Suborder Dicranocladina Schrammen, 1924 3 Suborder Pseudorhizomorina Schrammen, 1901 4 Suborder †Didymmorina Rauff, 1893 [monotypic]