- Caecum Fleming 1813
- Caelostomus W.S. MacLeay 1825
- Caenocephus Konow 1896
- Caesio Lacepède 1801
- Calameuta Konow 1896
- Calamiana Herre 1945
- Calathus Bonelli 1810
- Calcinus Dana 1852
- Caligus O.F. Müller 1785
- Callanthias Lowe 1839
- Callaspidia Dahlbom 1842
- Calleida Latreille & Dejean 1824
- Calliactis Verrill 1869
- Callianassa Learch 1814
- Calliarthron Manza 1937
- Callionymus Linnaeus 1758
- Callirhytis Forster 1869
- Callista Poli 1791
- Calliurichthys Jordan & Fowler 1903
- Callochiton Gray 1847
- Callogobius Bleeker 1874
- Callojoppa Cameron 1903
- Callorhinchus Lacépède 1798
- Calloria Cooper & Lee 1993
- Callosciurus Gray 1867
- Callyodon Gronow 1763
- Callyspongia Duchassaing & Michelotti 1864
- Calodium Dujardin 1845
- Calonectris Mathews & Iredale 1915
- Calosega Terayama 1999
- Calosoma Weber 1801
- Calotomus Gilbert 1890
- Calveriosoma Mortensen 1934
- Camallanus Railliet & Henry 1915
- Camellia Linné
- Campalita Motschulsky 1865
- Campages Heydley 1905
- Campanula Linné
- Camponotus Mayr 1861
- Campylaspis G.O. Sars 1865
- Canavalia Adanson
- Candidia D.S. Jordan & R.E. Richardson 1909
- Canis Linnaeus 1758
- Cantellius Ross & Newman 1973
- Cantharidus Montfort 1810
- Cantharus Röding 1798
- Canthidermis Swainson 1839
- Canthigaster Swainson 1839
- Canthocamptus Westwood 1836
- Capillaria Zeder 1800
- Capitella Blainville 1828
- Capitulum Gray 1825
- Capra Linnaeus 1758
- Caprella Lamarck 1801
- Caprodon Temminck & Schlegel 1843
- Carabus Linnaeus 1758
- C. (Aulonocarabus)
- C. (Limnocarabus)
- C. (Ohomopterus)
- Carangichthys Bleeker 1852
- Carangoides Bleeker 1851
- Caranx Lacépède 1801
- Carassius Nilsson 1832
- Carbula Stål 1864
- Carcharhinus de Blainville 1816
- Carcharias Rafinesque 1810
- Carcinobdella Oka 1910
- Carcinoplax H. Milne Edwards 1852
- Carcinoscorpius Pocock 1902
- Carcinus Leach 1814
- Cardiocondyla Emery 1869
- Cardiocranius Satunin 1903
- Cardiostrongylus Sakamoto & Malgor 1995
- Carebara Westwood 1840
- Careproctus Krøyer 1861
- Caretta Rafinesque 1814
- Carex Linné
- Caridina H. Milne Edwards 1837
- Carineogammarus Bousfield 1979
- Caristius T.N. Gill & H.M. Smith 1905
- Carolinensis Travassos 1937
- Carpinus Linné
- Carybdea Péron & Lesueur 1810
- Caryophyllia Lamarck 1801
- Cassatiovolvox
- Castanopsis Spach 1842
- Castor Linnaeus 1758
- Catapagurus A. Milne Edwards 1880
- Catops Paykull 1798
- Caudoeuraphia Poltarukha 1997
- Caulastraea Dana 1846
- Caulerpa J.V. Lamouroux 1809
- Caulleriella Chamberlin 1919
- Cayratia (Baker) Suess.
- Cecidomyzon Stock 1981
- Cellana H. Adams 1869
- Centrocestus Looss 1899
- Centrorhynchus Lühe 1911
- Cephalodella Bory de St. Vincent 1826
- Cephalopholis Bloch & Schneider 1801
- Cephaloscyllium Gill 1861
- Cephalothrix Örsted 1843
- Cephaluris Akhtar 1947
- Cephus Latreille 1802
- Cepola Linnaeus 1766
- Ceramium Roth 1797
- Cerapachys Smith 1857
- Cerasus Linné
- Ceratonereis Kinberg 1866
- Ceratochlamys Habe 1946
- Ceratopteris Brongniart
- Ceratostoma Herrmannsen 1846
- Ceratothoa Dana 1852
- Cercaria Müller 1773
- Cercion Navás 1907
- Cercopithifilaria Eberhard 1980
- Cercops Krøyer 1843
- Cerebratulus Renier 1804
- Cerithidea Swainson 1840
- Cerithideopsilla Thiele 1929
- Cerithium Bruguière 1789
- Cervus Linnaeus 1758
- Cestum Lesueur 1813
- Cettia Bonaparte 1834
- Chabertia Railliet & Henry 1909
- Chaenogobius Gill 1859
- Chaetoceros Ehrenberg 1844
- Chaetodon Linnaeus 1758
- Chaetodontoplus Bleeker 1876
- Chaetolepas Studer 1889
- Chaetospania Karsch 1886
- Chaeturichthys Richardson 1844
- Chalcosyrphus Curran 1925
- Chalybion Dahlbom 1843
- Chamaecyparis Spach 1842
- Chamaepericlymenum
- Chamaesyce S.F. Gray
- Chamalycaeus Kobelt & Moellendroff 1897
- Champsodon Günther 1867
- Channa Scopoli 1777
- Chara Linné 1753
- Charonia Gistel 1847
- Charybdis de Haan 1833
- Chasmagnathus de Haan 1833
- Chasmias Ashmead 1900
- Cheilio Lacépède 1802
- Cheilodactylus Lacépède 1803
- Cheilopogon Lowe 1841
- Cheilospirura Diesing 1861
- Chelidonichthys Kaup 1873
- Chelidoperca Boulenger 1895
- Chelomalpheus Kim 1998
- Chelon Artedi in Röse 1793
- Chelonia Brongniart 1800
- Chelydra Schweigger 1812
- Cheumatopsyche Wallengren 1891
- Chicoreus Montfort 1810
- Chilodonella Strand 1928
- Chilomycterus Brisout de Barneville 1846
- Chilorhinus Lütken 1852
- Chiloscyllium Müller & Henle 1837
- Chimarrogale Anderson 1877
- Chinemys Smith 1931
- Chionoecetes Krøyer 1838
- Chiromantes Gistel 1848
- Chlaenius Bonelli 1810
- Chlamys Röding 1798
- Chlidonophora Dall 1903
- Chloeia Savigny 1818
- Chlorostoma Swainson 1840
- Chlorurus Swainson 1839
- Choanotaenia Railliet 1896
- Choerades Walker 1851
- Choerodon Bleeker 1847
- Chondracanthus Delaroche 1811
- Chondria C. Agardh 1817
- Chondrocladia Thomson 1873
- Chondrophycus (Tokida & Saito) Garbary & Harper 1998
- Chondrus Stackhouse 1797
- Chordodes Creplin 1847
- Choriaster Lütken 1896
- Chorthippus Fieber 1852
- Chromis Cuvier 1814
- Chromogaster Lauterborn 1893
- Chrysanthemum Linné
- Chrysaora Péron & Lesueur 1810
- Chrysiptera Swainson 1839
- Chrysolophus J.E. Gray 1834
- Chrysopetalum Ehlers 1864
- Chthamalus Ranzani 1817
- Chymomyza Czerny 1903
- Cichlasoma Swainson 1839
- Cichlidogyrus Paperna 1960
- Cicindela Linnaeus 1758
- Ciliopagurus Forest 1995
- Cingulina A. Adams 1860
- Cinnamomum Schäffer
- Cionophorus Ross & Newman 2001
- Circeis Saint-Joseph 1894
- Circus Lacépède 1799
- Cirratulus Lamarck 1801
- Cirrhilabrus Temminck & Schlegel 1845
- Cirriformia Hartman 1936
- Cirripectes Swainson 1839
- Cirrisalarias Springer 1976
- Citellina Prendel 1928
- Citellinema Hall 1916
- Citellus Oken 1816
- Citharoides Hubbs 1915
- Citrus Linné
- Cladius Illiger 1807
- Cladopsammia Lacaze-Duthiers 1897
- Clariger D.S. Jordan & Snyder 1901
- Clarkcomanthus Rowe, Hoggett, Birtles & Vail 1986
- Clathrofenella Kuroda & Habe 1954
- Clavinema Yamaguti 1935
- Cleantioides Kensley & Kaufman 1978
- Cleisthenes Jordan & Starks 1904
- Clematis Linné
- Cleptes Latreille 1802
- Clerodendrum Linné
- Clethrionomys Tilesius 1850
- Clibanarius Dana 1852
- Clidoderma Bleeker 1862
- Clinostomum Leidy 1856
- Clinus Cuvier 1816
- Clithon Montfort 1810
- Clivina Latreille 1802
- Closterotomus Fieber 1858
- Clunio Haliday 1855
- Clupea Linnaeus 1758
- Clymene Savigny in Lamarck 1818
- Clypeaster Lamarck 1801
- Clypeomorus Jousseaume 1888
- Clytia Lamouroux 1812
- Cnemidaster Sladen 1889
- Cnemidocarpa Huntsman 1913
- Cnismatocentrum Dall 1920
- Cobitis Linnaeus 1758
- Cociella Whitley 1940
- Coecella Gray 1853
- Coelastrea Verrill 1866
- Coelodischela Vacelet, Vasseur & Lévi 1976
- Coeloplana Kowalevsky 1880
- Coelopleurus L. Agassiz 1840
- Coelorinchus Giorna 1809
- Coeloseris Vaughan 1918
- Coelostoma Brullé 1835
- Coenobita Latreille 1829
- Coffea Linné
- Colacium Ehrenberg 1834
- Collessia Bock 1982
- Colobopsis Mayr 1861
- Cololabis Gill 1869
- Colophospermum Kirk ex J.Léonard
- Colpocephalum Nitzsch 1818
- Colpodes W.S. Macleay 1825
- Colpomenia (Endlicher) Derbès & Solier 1851
- Columba Linnaeus 1758
- Colurella Bory De St. Vincent 1824
- Comanthus A.H. Clark 1908
- Commelina Linné
- Compsothyris Jackson 1918
- Conchyliurus Bocquet & Stock 1957
- Concinnum Bhalerao 1936
- Conger Bosc (ex Cuvier) 1817
- Coniglobus Pilsbry & Hirase 1906
- Conochiloides Hlava 1904
- Conochilus Ehrenberg 1834
- Conomurex Bayle in P. Fischer 1884
- Conspicuum Bhalerao 1936
- Contracaecum Railliet & Henry 1912
- Conus Linnaeus 1758
- Convoluta Ørsted 1843
- Conyza C.F. Lessing 1832
- Cookeolus Fowler 1929
- Cooperia Ransom 1907
- Copera Kirby 1890
- Copidaster A.H. Clark 1948
- Coptodera Dejean 1825
- Coptothyris Jackson 1918
- Copula Bentlage et al. 2010
- Corallina Linné 1758
- Coralliogalathea Baba & Javed 1974
- Corbicula Mergele von Mühlfeld 1811
- Coreoperca Herzenstein 1896
- Coridromius Signoret 1862
- Cornus Linné
- Coronaster Perrier 1885
- Corophium Latreille 1806
- Corvus Linnaeus 1758
- Corydoras Lacépède 1803
- Corymorpha M. Sars 1835
- Coryne Gaertner 1774
- Coryphaena Linnaeus 1758
- Coscinasterias Verrill 1870
- Cosmocephalus Molin 1858
- Cosmocerca Diesing 1861
- Cosmocercoides Wilkie 1930
- Cottus Linnaeus 1758
- Craesus Leach 1817
- Crangon Fabricius 1798
- Crangonobdella Selensky 1914
- Craspedacusta Lankester 1880
- Craspedochiton Shuttleworth 1853
- Craspedonotus Schaum 1863
- Craspedorrhynchus Kéler 1938
- Crassicauda Leiper & Atkinson 1914
- Crassinarke Takagi 1951
- Crassostrea Sacco 1897
- Crassotrema Park 1938
- Craterostomum Boulenger 1920
- Crematogaster Lund 1831
- Crenimugil L.P. Schultz 1946
- Crenosoma Molin 1861
- Crepidostomum Braun 1900
- Creusia Leach 1817
- Cricetulus Milne-Edwards 1867
- Cricetus Leske 1779
- Crinum Linné
- Crispatotrochus Tenison-Woods 1878
- Cristaria Schumacher 1817
- Cristatogobius Herre 1927
- Crocidula Wagler 1832
- Crocothemis Brauer 1868
- Cromileptes Swainson 1839
- Cronia H. Adams & A. Adams 1853
- Crossaster Müller & Troschel 1840
- Crossocerus Lepeletier & Brulle 1835
- Crossorhombus Regan 1920
- Cryptoblepharus Wiegmann 1834
- Cryptobranchus Leuckart 1821
- Cryptocentrus Ehrenberg 1837
- Cryptochiton Middendorff 1847
- Cryptocyclops G.O. Sars 1927
- Cryptomeria Linné
- Cryptoplax Blainville 1818
- Cryptopone Emery 1893
- Cryptopora Jeffreys 1869
- Ctenodiscus Müller & Troschel 1842
- Ctenogobiops Smith 1959
- Ctenopharyngodon Steindachner 1866
- Ctenophoraster Fisher 1906
- Ctenoplana Korotneff 1886
- Ctenopleura Fisher 1913
- Ctenotrypauchen Steindachner 1867
- Cuapetes Clark 1919
- Cuenotaster Thiéry in Koehler 1920
- Culicia Dana 1846
- Culcita Agassiz 1836
- Cumella G.O. Sars 1865
- Cumellopsis Calman 1905
- Cuora Gray 1856
- Cuspidella Hincks 1868
- Cyathelia Milne-Edwards & Haime 1849
- Cyathospirura Baylis 1934
- Cyathostomum Molin 1861
- Cyathura Norman & Stebbing 1886
- Cybister Curtis 1827
- Cyclina Deshayes 1850
- Cyclobalanopsis
- Cyclochaeta Jackson 1875
- Cyclophorus Monfort 1810
- Cyclopina Claus 1863
- Cyclops O.F. Müller 1785
- Cyclotus Swainson 1840
- Cylicocyclus Ihle 1922
- Cylicodontophorus Ihle 1922
- Cylicospirura Vevers 1922
- Cylicostephanus Ihle 1922
- Cylindera Westwood 1831
- Cymatium Röding 1798
- Cymindis Latreille 1806
- Cymolutes Günther 1861
- Cymothoa Fabricius 1787
- Cynoglossus Hamilton 1822
- Cynops Tschudi 1838
- Cyperus Linné
- Cyphastrea Milne-Edwards & Haime 1848
- Cyprinus Linnaeus 1758
- Cypselurus Swainson 1838
- Cyrnea Seurat 1914
- Cyrtopeltis Fieber 1860
- Cystobranchus Diesing 1859
- Cystomyzon Stock 1981