Phylum Porifera Grant, 1836 - sponges
   Subphylum Hexactinellida Schmidt, 1870 see Class Hexactinellida Schmidt, 1870
     Class Hexasterophora F.E. von Schulze see Subclass Hexasterophora Schulze, 1886
       Order Lyssacinosida Zittel, 1877
         Family Rossellidae Schulze, 1885
           Subfamily Acanthascinae Schulze, 1897
             Genus Rhabdocalyptus Schulze, 1886
               Rhabdocalyptus arcticus Brøndsted, 1916
               Rhabdocalyptus mollis F.E. von Schulze, 1886