Eukaryota Chatton, 1925 - eukaryotes see Domain Eukaryota Chatton, 1925
   Opisthokonta Cavalier-Smith, 1987 - opisthokonts see Clade Opisthokonta Cavalier-Smith 1987, nom. cl. inval.
     Metazoa Haeckel 1874 - multicellular animals see Kingdom Animalia Linnaeus, 1758
       Eumetazoa Bütschli, 1910 - eumetazoans
         Triploblastica see [unranked] Bilateria Hatschek, 1888
           Bilateria Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
             Deuterostomia Grobben, 1908 - deuterostomes see Infrakingdom Deuterostomia Grobben, 1908
               Phylum Hemichordata Bateson, 1885 - hemichordates
                 Class Pterobranchia Lankester, 1877 - pterobranchs
                   Genus Cephalodiscus M'Intosh, 1882