Phylum Porifera Grant, 1836 - sponges Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885 Subclass Ceractinomorpha Lévi, 1953 see Class Demospongiae Sollas, 1885 Order †Sigmatosclerophorida Burton, 1956 [monotypic] Family †Dystactospongiidae Miller, 1889 Genus †Heterospongia Ulrich, 1889