Phylum Porifera Grant, 1836 - sponges Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885 Subclass Clavaxinellida Lévi, 1956 Order Clavulina Vosmaer, 1887 Family Spirastrellidae Ridley & Dendy, 1886 1 Genus †Ditriaenella Hinde & Holmes, 1892 2 Genus †Spirastrella Schmidt, 1868