• Abietinaria abietina (Linnaeus, 1758)
• Abietinaria filicula (Ellis & Solander, 1786)
• Abietinaria fusca (Johnston, 1847)
• Abietinaria interversa (Pictet & Bedot, 1900)
• Abietinaria pulchra (Nutting, 1904)
• Abylopsis eschscholtzii (Huxley, 1859)
• Abylopsis tetragona (Otto, 1823)
• Acaulis primarius Stimpson, 1853
• Acauloides ammisatum Bouillon, 1965
• Acauloides ilonae (Brinckmann-Voss, 1966)
• Acryptolaria conferta (Allman, 1877)
• Acryptolaria crassicaulis (Allman, 1888)
• Acryptolaria longitheca (Allman, 1877)
• Actigia vanbenedeni (Hincks, 1869) accepted as Coryne vanbenedenii Hincks, 1868
• Aequorea aequorea (Forsskål, 1775) accepted as Aequorea forskalea Péron & Lesueur, 1810
• Aequorea conica Browne, 1905
• Aequorea forskalea Péron & Lesueur, 1810
• Aequorea macrodactyla (Brandt, 1835)
• Aequorea pensilis (Haeckel, 1879)
• Aequorea vitrina Gosse, 1853
• Agalma clausi Bedot, 1888
• Agalma elegans (M. Sars, 1846)
• Agalma okenii Eschscholtz, 1825
• Agalma rubra Vogt, 1852 accepted as Halistemma rubrum (Vogt, 1852)
• Agalmopsis utricularia Claus, 1879 accepted as Lychnagalma utricularia (Claus, 1879)
• Aglaophenia acacia Allman, 1883
• Aglaophenia elongata Meneghini, 1845
• Aglaophenia harpago Schenck, 1965
• Aglaophenia kirchenpaueri (Heller, 1868)
• Aglaophenia latecarinata Allman, 1877
• Aglaophenia lophocarpa Allman, 1877
• Aglaophenia octodonta (Heller, 1868)
• Aglaophenia parvula Bale, 1882
• Aglaophenia picardi Svoboda, 1979
• Aglaophenia pluma (Linnaeus, 1758)
• Aglaophenia tubiformis Marktanner-Turneretscher, 1890
• Aglaophenia tubulifera (Hincks, 1861)
• Aglaophenopsis bonnevieae (Jäderholm, 1909)
• Aglaophenopsis cartieri (Bedot, 1921)
• Aglaophenopsis cornuta (Fewkes, 1881)
• Amalthaea sarsii (Steenstup, 1854) accepted as Corymorpha sarsii Steenstrup, 1855
• Amphicaryon acaule Chun, 1888
• Amphicaryon ernesti Totton, 1954
• Amphicaryon peltifera (Haeckel, 1888)
• Amphinema biscayana (Browne, 1907)
• Amphinema dinema (Péron & Lesueur, 1810)
• Amphinema krampi Russell, 1956
• Amphinema rubrum (Kramp, 1957)
• Amphinema rugosum (Mayer, 1900)
• Amphinema turrida (Mayer, 1900)
• Amphisbetia distans (Lamouroux, 1816)
• Amphisbetia operculata (Linnaeus, 1758)
• Angelopsis euryale Pugh, 1983
• Annatiara affinis (Hartlaub, 1914)
• Antennella ansini Peña Cantero & García Carrascosa, 2002
• Antennella paucinoda Fraser, 1935 accepted as Antennella quadriaurita Ritchie, 1909
• Antennella quadriaurita Ritchie, 1909
• Antennella secundaria (Gmelin, 1791)
• Antennella siliquosa (Hincks, 1877)
• Antennularia indivisa Lamarck, 1816 accepted as Nemertesia antennina (Linnaeus, 1758)
• Anthohebella parasitica (Ciamician, 1880)
• Apolemia uvaria (Lesueur, 1815)
• Archisoma natans Bigelow, 1911 accepted as Nectopyramis natans (Bigelow, 1911)
• Aselomaris arenosa (Alder, 1862) accepted as Rhizorhagium arenosum (Alder, 1862)
• Aselomaris michaeli Berrill, 1948 accepted as Pachycordyle michaeli (Berrill, 1948)
• Athorybia rosacea (Forsskål, 1775)
• Barcino foixensis Gili, Bouillon, Pagès, Palanques & Puig, 1999
• Bargmannia amoena Pugh, 1999
• Bargmannia elongata Totton, 1954
• Bargmannia lata Mapstone, 1998
• Bassia bassensis (Quoy & Gaimard, 1833)
• Bathyphysa conifera (Studer, 1878)
• Bedotella armata (Pictet & Bedot, 1900)
• Bimeria vestita Wright, 1859
• Blackfordia virginica Mayer, 1910
• Bonneviella grandis (Allman, 1876)
• Boreohydra simplex Westblad, 1937 accepted as Plotocnide borealis Wagner, 1885
• Bougainvillia britannica (Forbes, 1841)
• Bougainvillia charcoti Le Danois, 1913 accepted as Nemopsis bachei L. Agassiz, 1849
• Bougainvillia flavida Hartlaub, 1897 accepted as Bougainvillia britannica (Forbes, 1841)
• Bougainvillia macloviana Lesson, 1830
• Bougainvillia multicilia (Haeckel, 1879) (uncertain > taxon inquirendum)
• Bougainvillia muscoides (Sars, 1846)
• Bougainvillia muscus (Allman, 1863)
• Bougainvillia principis (Steenstrup, 1850)
• Bougainvillia pyramidata (Forbes & Goodsir, 1853)
• Bougainvillia ramosa (Van Beneden, 1844) accepted as Bougainvillia muscus (Allman, 1863)
• Bougainvillia rugosa Clarke, 1882
• Bougainvillia superciliaris (L. Agassiz, 1849)
• Bouillonactinia hooperii (Sigerfoos, 1899)
• Bouillonia cornucopia (Bonnevie, 1898)
• Branchiocerianthus italicus Stechow, 1921
• Branchiocerianthus norvegicus Brattström, 1956
• Bythotiara murrayi Günther, 1903
• Calycella gracilis Hartlaub, 1897 (uncertain > taxon inquirendum)
• Calycella hispida (Nutting, 1896)
• Calycella syringa (Linnaeus, 1767)
• Calycopsis gara Petersen, 1957
• Calycopsis krampi Petersen, 1957
• Calycopsis simplex Kramp & Damas, 1925