Hemichordata Bateson, 1885
Acoelothecia John, 1931
Atubaridae
Atubariidae
Calyxhydra Kozlowski, 1959
Cephalodiscidae Harmer, 1905
Cylindrotheca Eisenack, 1934
Diplohydra Kozlowski, 1949
Eocephalodiscidae Kozlowski, 1949
Graptovermis Kozlowski, 1949
Halilophus M. Sars, 1869
Lagenohydra Kozlowski, 1959
Melanostrophus Öpik, 1931
Palaeotuba Eisenack, 1934
Rhabdopleuridae Harmer, 1905
Rhapdopleura
Stolonodendridae Bulman, 1955
Stolonodendrum Kozlowski, 1948
Trimerohydra Kozlowski, 1959
