Phylum Porifera Grant, 1836 - sponges Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885 Subclass Ceractinomorpha Lévi, 1953 see Class Demospongiae Sollas, 1885 Order Halichondrida Vosmaer, 1887 1 Family Halichondriidae Gray, 1867 2 ?Family †Hymeniacidonidae de Laubenfels, 1936 see Family Halichondriidae Gray, 1867