• Acorania enmediensis López-Fé, 2006
• Adeonella calveti Canu & Bassler, 1930
• Adeonella pallasii (Heller, 1867)
• Adeonella polystomella (Reuss, 1848)
• Adeonellopsis coscinophora (Reuss, 1848)
• Adeonellopsis distoma (Busk, 1858)
• Adeonellopsis multiporosa Aristegui, 1985
• Aetea anguina (Linnaeus, 1758)
• Aetea azorensis Calvet, 1903 accepted as Aetea sica (Couch, 1844)
• Aetea lepadiformis Waters, 1906
• Aetea ligulata Busk, 1852
• Aetea longicollis (Jullien, 1903)
• Aetea sica (Couch, 1844)
• Aetea truncata (Landsborough, 1852)
• Aethozoon pellucidum Hayward, 1978
• Alcyonidioides mytili (Dalyell, 1848)
• Alcyonidium albidum Alder, 1857
• Alcyonidium candidum Ryland, 1963
• Alcyonidium cellarioides Calvet, 1900
• Alcyonidium condylocinereum Porter, 2004
• Alcyonidium diaphanum (Hudson, 1778)
• Alcyonidium disciforme Smitt, 1872
• Alcyonidium duplex Prouho, 1892
• Alcyonidium gelatinosum (Linnaeus, 1761)
• Alcyonidium hirsutum (Fleming, 1828)
• Alcyonidium hydrocoalitum Porter, 2004
• Alcyonidium mamillatum Alder, 1857
• Alcyonidium mytili Dalyell, 1848 accepted as Alcyonidioides mytili (Dalyell, 1848)
• Alcyonidium parasiticum (Fleming, 1828)
• Alcyonidium polyoum (Hassall, 1841)
• Alcyonidium reticulum Ryland & Porter, 2000 accepted as Alcyonidium gelatinosum (Linnaeus, 1761)
• Alcyonidium variegatum Prouho, 1892
• Alcyonidium vicarians d'Hondt & Chimenz Gusso, 2006
• Alderina canariensis López-Fé, 2006 accepted as Kenoaplousina canariensis (López-Fé, 2006)
• Alderina imbellis (Hincks, 1860)
• Alderina solidula (Hincks, 1860) accepted as Crassimarginatella solidula (Hincks, 1860)
• Allantopora minuta (Harmelin, 1973)
• Amathia arctica (Busk, 1880)
• Amathia citrina (Hincks, 1877)
• Amathia distans Busk, 1886
• Amathia gracilis (Leidy, 1855)
• Amathia gracillima (Hincks, 1877)
• Amathia guernseii Chimonides, 1987
• Amathia imbricata (Adams, 1800)
• Amathia intermedis Chimonides, 1987
• Amathia lendigera (Linnaeus, 1758)
• Amathia pruvoti Calvet, 1911
• Amathia pusilla (Jullien, 1903)
• Amathia pustulosa (Ellis & Solander, 1786)
• Amathia semiconvoluta Lamouroux, 1824
• Amathia tortuosa Tenison-Woods, 1880
• Amathia verticillata (delle Chiaje, 1822)
• Amathia vidovici (Heller, 1867)
• Ammatophora nodulosa (Hincks, 1877)
• Amphiblestrum (Aviculamphiblestrum) ruggeroi Rosso, 1999
• Amphiblestrum auritum (Hincks, 1877)
• Amphiblestrum flemingii (Busk, 1854)
• Amphiblestrum lyrulatum (Calvet, 1907)
• Amphiblestrum minax accepted as Ramphonotus minax (Busk, 1860)
• Amphiblestrum ruggeroi Rosso, 1999 represented as Amphiblestrum (Aviculamphiblestrum) ruggeroi Rosso, 1999
• Amphiblestrum septentrionalis (Kluge, 1906) accepted as Ramphonotus septentrionalis (Kluge, 1906)
• Amphiblestrum solidum (Packard, 1863)
• Anarthropora monodon (Busk, 1860)
• Anguinella palmata Van Beneden, 1845
• Annectocyma arcuata (Harmelin, 1976)
• Annectocyma indistincta (Canu & Bassler, 1929) accepted as Harmelinopora indistincta (Canu & Bassler, 1929)
• Annectocyma major (Johnston, 1847)
• Annectocyma tubulosa (Busk, 1875)
• Antarctothoa galaica (Cesar-Aldariz, Fernández-Pulpeiro & Reverter-Gil, 1999)
• Aplousina capriensis (Waters, 1898)
• Aplousina filum (Jullien & Calvet, 1903)
• Aquiloniella scabra (van Beneden, 1848)
• Arachnidium clavatum Hincks, 1877
• Arachnidium fibrosum Hincks, 1880
• Arachnidium hippothooides Hincks, 1859
• Arachnidium lacourti d'Hondt & Faasse, 2006
• Arachnoidea annosciae d'Hondt & Geraci, 1976 accepted as Arachnoidella annosciae (d'Hondt & Geraci, 1976)
• Arachnoidea dubia d'Hondt, 1976 accepted as Arachnoidella dubia (d'Hondt, 1976)
• Arachnoidea prenanti d'Hondt, 1976 accepted as Arachnoidella prenanti (d'Hondt, 1976)
• Arachnoidea protecta Harmer, 1915 accepted as Arachnoidella protecta Harmer, 1915
• Arachnoidea thalassae (d'Hondt, 1978) accepted as Arachnoidella thalassae (d'Hondt, 1979)
• Arachnoidella annosciae (d'Hondt & Geraci, 1976)
• Arachnoidella dubia (d'Hondt, 1976)
• Arachnoidella prenanti (d'Hondt, 1976)
• Arachnoidella protecta Harmer, 1915
• Arachnoidella thalassae (d'Hondt, 1979)
• Arctonula arctica (M. Sars, 1851)
• Arthropoma cecilii (Audouin, 1826)
• Ascorhiza mawatarii d'Hondt, 1983
• Ascosia pandora Jullien, 1882
• Aspidelectra melolontha (Landsborough, 1852)
• Bantariella verticillata (Heller, 1867)
• Bathysoecia polygonalis (Kluge, 1952) accepted as Oncousoecia polygonalis (Kluge, 1915)
• Beania cylindrica (Hincks, 1886)
• Beania hirtissima (Heller, 1867)
• Beania hirtissima cylindrica (Hincks, 1886) accepted as Beania cylindrica (Hincks, 1886)
• Beania magellanica (Busk, 1852)
• Beania mirabilis Johnston, 1840
• Beania robusta (Hincks, 1881) accepted as Beania mirabilis Johnston, 1840
• Beania thula Hayward, 1994