• Abedinium dasypus (Cachon & Cachon-Enjumet) Loeblich Jr & Loeblich III, 1966
• Abratopdinium cardioforme S.Mao & B.A.R.Mohr †
• Abratopdinium kerguelense S.Mao & B.A.R.Mohr †
• Acanthaulax aceras (Eisenack) Stover & Evitt (uncertain)
• Acanthaulax aculeata (Klement) Stover & Evitt (uncertain)
• Acanthaulax angulosa (Gitmez) Stover & Evitt (uncertain)
• Acanthaulax spinosissima (Deflandre) Sarjeant (uncertain)
• Acanthaulax venusta (Klement) Sarjeant (uncertain)
• Acanthodinium caryophyllum Kofoid, 1907
• Acanthodinium spinosum Kofoid, 1907 accepted as Cladopyxis spinosa (Kofoid) Schiller
• Acanthogonyaulax spinifera (Murray & Whitting) H.W.Graham, 1942
• Acanthogonyaulax venusta (Klement) Sarjeant (uncertain)
• Acanthostomella conicoides Kofoid & Campbell, 1929
• Acanthostomella elongata Kofoid & Campbell, 1929 (uncertain > nomen dubium)
• Acanthostomella gracilis Brandt, 1896 (uncertain > nomen dubium)
• Acanthostomella lata Kofoid & Campbell, 1929
• Acanthostomella minutissima Kofoid & Campbell, 1929
• Acanthostomella norvegica (Daday, 1887)
• Acanthostomella obtusa Kofoid & Campbell, 1929
• Acaryophrya collaris Kahl, 1926
• Achomosphaera alcicornu (Eisenack) R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera antleriformis P.Schiøler †
• Achomosphaera argesensis E.Demetrescu †
• Achomosphaera gralliforme (Brosius) R.J.Davey & G.L.Williams, 1969 †
• Achomosphaera hirundo (Eisenack) R.J.Davey & G.L.Williams, 1969 †
• Achomosphaera hyperacantha (Deflandre & Cookson) R.J.Davey & G.L.Williams, 1969 † accepted as Gonyaulax spinifera (Claparède & Lachmann) Diesing, 1866
• Achomosphaera improcera M.A.Islam, 1983 †
• Achomosphaera linifera (Cookson & Eisenack) Stover & Evitt, 1978 †
• Achomosphaera neptuni (Eisenack) R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera ramulifera (Deflandre) Evitt (uncertain)
• Achomosphaera ramulifera var. perforata R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera recurvata K.P.Jain, S.C.D.Sah & R.Y.Singh †
• Achomosphaera regiensis Corradini (uncertain)
• Achomosphaera sagena R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera septata (Cookson & Eisenack) Stover & Evitt (uncertain)
• Achomosphaera triangulata (Gerlach) R.J.Davey & G.L.Williams, 1969 †
• Achradina angusta Lohmann, 1920 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra Lohmann, 1903 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. aciculata Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. angustata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. nervosa Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. reticulata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. spatulata Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. sulcata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. truncata Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina reticulata Lohmann, 1920 accepted as Achradina pulchra f. reticulata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina sulcata Lohmann, 1920 accepted as Monaster rete F.Schütt, 1895
• Acineria incurvata Dujardin, 1841
• Acineria nasuta Lepsi, 1962
• Acineta amphiasci Precht, 1935
• Acineta branchicola Precht, 1935
• Acineta compressa Claparède & Lachmann, 1859
• Acineta corophii Collin, 1912
• Acineta craterellus Collin, 1909 accepted as Anthacineta craterellus (Collin, 1909) Jankowski, 1978
• Acineta excirolensis Fernandez-Leborans, Yukio & Keizo, 2003
• Acineta foetida Maupas, 1881
• Acineta grahami Allgin, 1955
• Acineta harpacticicola Precht, 1935
• Acineta hokkaidensis Fernandez-Leborans, Yukio & Keizo, 2003
• Acineta laevis Dons, 1918
• Acineta laomedeae Precht, 1935
• Acineta papillifera Keppen, 1888
• Acineta pyriformis Stokes, 1891
• Acineta schulzi Kahl, 1934
• Acineta sulcata Dons, 1927
• Acineta tuberosa Ehrenberg, 1833
• Acinetides symbiotica (Daday, 1907) Curds, 1985
• Acinetoides greeffii Plate, 1888 accepted as Hypocoma parasitica Gruber, 1884
• Acinetoides zoothamni Plate, 1888 accepted as Hypocoma parasitica Gruber, 1884
• Actiniscus biseptenarius Ehrenberg (uncertain)
• Actiniscus canadensis Bursa ex Carty, 2014
• Actiniscus chaixi E.Paréjas (uncertain)
• Actiniscus colleti Paréjas, 1934 † accepted as Discoaster colletii (Paréjas) Bersier, 1939 †
• Actiniscus duodenarius simplex Ehrenberg (uncertain)
• Actiniscus elegans (Ehrenberg) Ehrenberg (uncertain)
• Actiniscus elongatus Dumitrică, 1968 †
• Actiniscus flosculus S.Locker & E.Martini, 1986 †
• Actiniscus heptagonus Ehrenberg (uncertain)
• Actiniscus laciniatus S.Locker & E.Martini, 1986 †
• Actiniscus lancearius Ehrenberg (uncertain)
• Actiniscus pennatus Grunow, 1882 accepted as Corethron pennatum (Grunow) Ostenfeld, 1909
• Actiniscus pentasterias (Ehrenberg) Ehrenberg, 1844
• Actiniscus pentasterias var. arcticus Bursa ex Moestrup & Calado, 2018
• Actiniscus quinarius Ehrenberg (uncertain)
• Actiniscus radicula Dumitrică (uncertain)
• Actiniscus rota Ehrenberg (uncertain)
• Actiniscus septenarius Ehrenberg (uncertain)
• Actiniscus sexfurcatus Ehrenberg (uncertain)
• Actiniscus squamosus S.Locker & E.Martini, 1986 †
• Actiniscus stella (Ehrenberg) Ehrenberg, 1844 † accepted as Discoaster aster Bramlette & W.R.Riedel, 1954 †
• Actiniscus talmadgei D.L.Parke (uncertain)
• Actiniscus tetras Ehrenberg (uncertain)
• Actiniscus varians (H.S.Lauder) Grunow, 1882 accepted as Bacteriastrum hyalinum Lauder, 1864
• Actinocyathula crenata (Fraipont, 1878) Curds, 1987
• Actinocyathula homari (Sand, 1899) Curds, 1987
• Actinodinium apsteinii Chatton & Hovasse
• Actinodinium paradoxum (M.Rose & J.Cachon) Hollande & Enjumet, 1953 accepted as Cachonella paradoxa (M.Rose & J.Cachon) M.Rose & J.Cachon, 1952
• Actinotheca aphroditae Cookson & Eisenack, 1960 †
• Actinotheca ornata Cookson & Eisenack (uncertain)
• Actinotheca rara Corradini (uncertain)