• Abietinaria abietina (Linnaeus, 1758)
• Abietinaria filicula (Ellis & Solander, 1786)
• Abietinaria kincaidi (Nutting, 1901)
• Abietinaria pulchra (Nutting, 1904)
• Abietinaria turgida (Clark, 1877)
• Acanella arbuscula (Johnson, 1862)
• Acanthogorgia armata Verrill, 1878
• Acaulis primarius Stimpson, 1853
• Actinauge cristata Riemann-Zürneck, 1986
• Actinauge longicornis (Verrill, 1882)
• Actinauge rugosa Verrill, 1922 accepted as Hormathia nodosa (Fabricius, 1780)
• Actinauge verrilli McMurrich, 1893 accepted as Actinauge verrillii McMurrich, 1893
• Actinauge verrillii McMurrich, 1893
• Actinernus nobilis Verrill, 1879
• Actinia nitida Dawson, 1858 accepted as Stomphia coccinea (Müller, 1776)
• Actinia obtruncata Stimpson, 1853
• Actinia sipunculoides Stimpson, 1853 accepted as Edwardsia sipunculoides (Stimpson, 1853)
• Actinostola callosa (Verrill, 1882)
• Actinostola groenlandica Carlgren, 1899
• Actinostola spetsbergensis Carlgren, 1893 accepted as Glandulactis spetsbergensis (Carlgren, 1893)
• Actinothoe modesta (Verrill, 1866)
• Adamsia sociabilis Verrill, 1882 accepted as Calliactis sociabilis (Verrill, 1882)
• Aegina citrea Eschscholtz, 1829
• Aeginopsis laurentii Brandt, 1838
• Aequorea aequorea (Forsskål, 1775) accepted as Aequorea forskalea Péron & Lesueur, 1810
• Aequorea albida A. Agassiz, 1862
• Aequorea ciliata Eschscholtz, 1829 (uncertain > taxon inquirendum)
• Aequorea coerulescens (Brandt, 1835)
• Aequorea forskalea Péron & Lesueur, 1810
• Aequorea victoria (Murbach & Shearer, 1902)
• Aequorea vitrina Gosse, 1853
• Agalma elegans (M. Sars, 1846)
• Aglantha digitale (O. F. Müller, 1776)
• Aglantha digitalis (O.F. Mueller, 1776) accepted as Aglantha digitale (O. F. Müller, 1776)
• Alcyonium digitatum Linnaeus, 1758
• Allantactis parasitica Danielssen, 1890
• Amphianthus mirabilis (Verrill, 1879)
• Amphicaryon acaule Chun, 1888
• Anthelia borealis (Koren & Danielssen, 1883) accepted as Clavularia borealis Koren & Danielssen, 1883
• Antholoba achates (Drayton in Dana, 1846)
• Antholoba perdix (Verrill, 1882)
• Anthomastus agassizii Verrill, 1922
• Anthomastus grandiflorus Verrill, 1878
• Anthoptilum grandiflorum (Verrill, 1879)
• Anthothela grandiflora (Sars, 1856)
• Apolemia contorta (Margulis, 1976)
• Arachnactis brachiolata A. Agassiz, 1863 accepted as Synarachnactis brachiolata (A. Agassiz, 1863)
• Aselomaris michaeli Berrill, 1948 accepted as Pachycordyle michaeli (Berrill, 1948)
• Astrangia poculata (Ellis & Solander, 1786)
• Atolla wyvillei Haeckel, 1880
• Aulactinia stella (Verrill, 1864)
• Aurelia aurita (Linnaeus, 1758)
• Aurelia labiata Chamisso & Eysenhardt, 1821
• Aurelia limbata Brandt, 1835
• Balticina finmarchica (Sars, 1851)
• Bargmannia elongata Totton, 1954
• Bargmannia lata Mapstone, 1998
• Bicidiopsis tubicola Verrill, 1922 accepted as Peachia parasitica (Agassiz, 1861)
• Bolocera tuediae (Johnston, 1832)
• Bougainvillia bougainvillei (Brandt, 1835) (uncertain > taxon inquirendum)
• Bougainvillia carolinensis (McCrady, 1859)
• Bougainvillia multitentaculata Foerster, 1923
• Bougainvillia muscoides (Sars, 1846)
• Bougainvillia muscus (Allman, 1863)
• Bougainvillia principis (Steenstrup, 1850)
• Bougainvillia ramosa (Van Beneden, 1844) accepted as Bougainvillia muscus (Allman, 1863)
• Bougainvillia rugosa Clarke, 1882
• Bougainvillia superciliaris (L. Agassiz, 1849)
• Bunodactis stella (Verrill, 1864) accepted as Aulactinia stella (Verrill, 1864)
• Bythotiara huntsmani (Fraser, 1911)
• Calliactis sociabilis (Verrill, 1882)
• Calycella syringa (Linnaeus, 1767)
• Calycopsis birulai (Linko, 1913) accepted as Eumedusa birulai (Linko, 1913)
• Calyptospadix cerulea Clarke, 1882
• Campanularia crenata (Hartlaub, 1901) accepted as Orthopyxis crenata (Hartlaub, 1901)
• Campanularia edwardsi Nutting, 1901 accepted as Clytia hemisphaerica (Linnaeus, 1767)
• Campanularia groenlandica Levinsen, 1893
• Campanularia hincksii Alder, 1856
• Campanularia neglecta (Alder, 1856) accepted as Laomedea neglecta Alder, 1856
• Campanularia volubilis (Linnaeus, 1758)
• Campanulina lacerata (Johnston, 1847) accepted as Opercularella lacerata (Johnston, 1847)
• Campanulina pumila (Clark, 1875)
• Candelabrum phrygium (Fabricius, 1780)
• Capnella florida (Rathke, 1806) accepted as Duva florida (Rathke, 1806)
• Capnella glomerata (Verrill, 1869) accepted as Drifa glomerata (Verrill, 1869)
• Capnella glomerata f. flavescens (Danielssen, 1887)
• Catablema vesicarium (A. Agassiz, 1862)
• Ceriantheopsis americana (Agassiz in Verrill, 1864)
• Cerianthus borealis Verrill, 1873 accepted as Pachycerianthus borealis (Verrill, 1873)
• Chelophyes appendiculata (Eschscholtz, 1829)
• Chiropsalmus quadrumanus (F. Muller, 1859)
• Chrysaora melanaster Brandt, 1835
• Chrysogorgia agassizii (Verrill, 1883)
• Chuniphyes moserae Totton, 1954
• Chuniphyes multidentata Lens & van Riemsdijk, 1908
• Cladonema californicum Hyman, 1947
• Clausophyes moserae Margulis, 1988
• Clava multicornis (Forsskål, 1775)
• Clavularia alba (Grieg, 1888) (uncertain > taxon inquirendum)
• Clavularia arctica (Sars, 1860)