Phylum Porifera Grant, 1836 - sponges
   Class Demospongea Sollas, 1875 see Class Demospongiae Sollas, 1885
     Subclass †Lithistida Schmidt, 1870
       Order Megalithistida Reid, 2004
         Suborder †Helomorina Schrammen, 1924 [monotypic]
           Family †Carterellidae Schrammen, 1901
             1 Subfamily †Carterellinae Schrammen, 1901
             2 Subfamily †Isoraphiniinae Schrammen, 1924 see Family Isoraphiniidae Schrammen, 1924