Acaulis primarius Stimpson, 1853 (redescription)
Acauloides ammisatum Bouillon, 1965 (redescription)
Boreohydra simplex Westblad, 1937 accepted as Plotocnide borealis Wagner, 1885 (redescription)
Candelabrum cocksii (Cocks, 1854) (redescription)
Corymorpha nana Alder, 1857 (redescription)
Corymorpha nutans M. Sars, 1835 (redescription)
Coryne eximia Allman, 1859 (additional source)
Coryne muscoides (Linnaeus, 1761) (additional source)
Coryne pusilla Gaertner, 1774 (additional source)
Ectopleura L. Agassiz, 1862 (redescription)
Ectopleura crocea (Agassiz, 1862) (redescription)
Ectopleura dumortierii (Van Beneden, 1844) (redescription)
Ectopleura larynx (Ellis & Solander, 1786) (additional source)
Ectopleura wrighti Petersen, 1979 (redescription)
Eucodonium brownei Hartlaub, 1907 (redescription)
Eudendrium album Nutting, 1898 (redescription)
Eudendrium annulatum Norman, 1864 (redescription)
Eudendrium arbuscula Wright, 1859 (redescription)
Eudendrium capillare Alder, 1856 (redescription)
Eudendrium capillaroides Schuchert, 2008 (redescription)
Eudendrium glomeratum Picard, 1952 (redescription)
Eudendrium racemosum (Cavolini, 1785) (redescription)
Eudendrium rameum (Pallas, 1766) (additional source)
Eudendrium ramosum (Linnaeus, 1758) (additional source)
Eudendrium vaginatum Allman, 1863 (redescription)
Eudendrium vervoorti Marques & Migotto, 1998 (additional source)
Euphysa aurata Forbes, 1848 (redescription)
Euphysa tentaculata Linko, 1905 (redescription)
Hybocodon prolifer Agassiz, 1860 (redescription)
Hydra circumcincta Schulze, 1914 (redescription)
Hydra vulgaris Pallas, 1766 (redescription)
Hydractinia proboscidea (Hincks, 1868) (redescription)
Lizzia blondina Forbes, 1848 (redescription)
Margelopsis haeckelii Hartlaub, 1897 (redescription)
Paratiara digitalis Kramp & Damas, 1925 (redescription)
Pliobothrus symmetricus Pourtalès, 1868 (redescription)
Plotocnide borealis Wagner, 1885 (redescription)
Protohydra leuckarti Greeff, 1870 (redescription)
Psammohydra nanna Schulz, 1950 (redescription)
Stylaster gemmascens (Esper, 1790) (redescription)
Stylaster norvegicus (Gunnerus, 1768) (redescription)
Trichydra pudica Wright, 1857 (redescription)
Tubularia indivisa Linnaeus, 1758 (redescription)