Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Porifera Grant, 1836 - sponges
     Class Demospongiae Sollas, 1885 - demosponges
       Subclass Lithistida Schmidt, 1870
         1 Order †Orchocladina Rauff, 1895
         2 Order Tetralithistida Lagneau-Hérenger, 1962
         3 Order Megalithistida Reid, 2004
         4 Order Axinellida Lévi, 1953 see Order Halichondrida Vosmaer, 1887
         5 Order Monalithistida Lagneau-Hérenger, 1955
         6 Order Spirosclerophorida Reid, 1963 [monotypic]