Phylum Porifera Grant, 1836 - sponges Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885 Subclass †Lithistida Schmidt, 1870 Order Monalithistida Lagneau-Hérenger, 1955 1 Suborder †Megarhizomorina Schrammen, 1924 [monotypic] 2 Suborder Sphaerocladina Schrammen, 1910