• Ambiphrya miri Raabe, 1952
• Ancistrospira veneris Chatton & Lwoff, 1926
• Ancistrum abrarum Fenchel, 1965
• Ancistrum arcopagiae Fenchel, 1965
• Ancistrum caudatum Fenchel, 1964
• Ancistrum crassum Fenchel, 1965
• Ancistrum cyclidioides (Issel, 1918)
• Ancistrum dosiniae Chatton & Lwoff, 1926
• Ancistrum hydrobiae Raabe, 1936
• Ancistrum isseli Kahl, 1931
• Ancistrum japonicum (Uyemura, 1937)
• Ancistrum macomae Chatton & Lwoff, 1949
• Ancistrum mytili (Quennerstedt, 1867)
• Ancistrum nuculae Fenchel, 1965
• Ancistrum venerupis Fenchel, 1965
• Ancistrumina kofoidi (Busch, 1937)
• Anophrys arenicola Fernandez-Leborans, 1986
• Anophrys sarcophaga Cohn, 1866
• Anoplophrya macronucleata Wichterman, 1942
• Anoplophrya mytili Delphy, 1938
• Anoplophryopsis ovata de Puytorac, 1954
• Apisoma piscola
• Askoella janssoni Fenchel, 1965
• Biggaria bermudensis (Biggar & Wenrich, 1932) Aescht, 2001
• Biggaria echinometris (Biggar & Wenrich, 1932) Aescht, 2001
• Boveria labialis Ikeda & Ozaki, 1918
• Boveria subcylindrica Steven, 1901
• Boveria teredinidi Nelson, 1923
• Calyptotricha lanuginosa (Penard, 1922) Wilbert & Foissner, 1980
• Campanella cantieeri
• Campanella umbellaria (L.)
• Carchesium duplicatum Precht, 1935
• Carchesium gammari Precht, 1935
• Carchesium granulatum
• Carchesium jaerae Precht, 1935
• Carchesium pectinatum (Zacharias, 1897) Kahl, 1935
• Carchesium polypinum Linnaeus, 1758
• Carchesium spectabile Ehrenberg-Claparède & Lachmann, 1858
• Carchesium steinii Wrzesniowski, 1877
• Cardiostomatella minuta Dragesco, 1965
• Cardiostomatella mononucleata Dragesco, 1960
• Cardiostomatella vermiforme (Kahl, 1928) accepted as Cardiostomatella vermiformis (Kahl, 1928) Aescht, 2001
• Cardiostomatella vermiformis (Kahl, 1928) Aescht, 2001
• Chromidina coronata (Foettinger, 1881)
• Chromidina elegans (Foettinger, 1881)
• Cinetochilum impatiens Penard, 1922
• Cinetochilum margaritaceum Perty, 1852
• Cinetochilum marinum Kahl, 1931
• Cinetochilum mirum Penard, 1922
• Cinetochilum ovale Gong & Song, 2009
• Coelosomides marina Anigstein, 1912
• Coelosomides tessieri Dragesco, 1954
• Coelosomides vermiformis Burkovsky, 1970
• Cohnilembus caeci Powers, 1935
• Cohnilembus punctatus (Kahl, 1928) Kahl, 1933
• Cohnilembus pusillus (Quennerstedt, 1869) Kahl, 1928
• Cohnilembus stichotricha Kahl, 1928
• Cohnilembus velifer Cohn, 1866
• Cohnilembus vermiformis Kahl, 1931
• Cohnilembus verminus (Müller, 1786) Kahl, 1933
• Colpidium campylum (Stokes, 1886) Bresslau, 1922
• Colpidium campylum Stokes
• Colpidium colpoda (Ehr.)
• Colpoda aspera Kahl, 1926
• Colpoda cucullus O.F. Müller, 1786
• Colpoda henneguyi Fabre-Dom.
• Colpoda inflata Stokes, 1885
• Colpoda maupasi Enriquez, 1908
• Colpoda spiralis Novotny, Lynn & Evans, 1977
• Colpoda steini Maupas, 1883
• Colpoda steinii Maupas, 1883
• Conchostoma longissimum Fauré-Fremiet, 1963
• Conidophrys pilisuctor Chatton & Lwoff, 1934
• Cothurina nodosa
• Cothurnia acuta Levander, 1915
• Cothurnia annulata Stokes
• Cothurnia antarctica (Daday) Warren & Paynter, 1991
• Cothurnia arcuata Mereschkowsky, 1879
• Cothurnia borealis (Hensen, 1890) Ostenfeld, 1916
• Cothurnia calix Kahl, 1933
• Cothurnia canthocampti
• Cothurnia ceramicola Kahl, 1933
• Cothurnia coarctata Kahl, 1933
• Cothurnia complanata Precht, 1935
• Cothurnia cordylophorea Kahl, 1933
• Cothurnia cypridicola Kahl, 1933
• Cothurnia fecunda Stokes, 1893
• Cothurnia gammari Precht, 1935
• Cothurnia grandis (Perty)
• Cothurnia guyanensis Fernandez-Leborans & Sorbe, 2003
• Cothurnia halacaricola Precht, 1935
• Cothurnia harpactici Kahl, 1933
• Cothurnia innata O.F. Müller, 1786
• Cothurnia limnoriae Dons, 1927
• Cothurnia maritima Ehrenberg, 1838
• Cothurnia nebaliae Dons, 1927
• Cothurnia nereicola Precht, 1935
• Cothurnia nitocrae Precht, 1935
• Cothurnia oblonga Kahl, 1935
• Cothurnia ovalis Kahl, 1933