• Cadulus Philippi, 1844
• Camulus Distant, 1918 (uncertain)
• Capulus Montfort, 1810
• Catulus D.W. Malloch & C.T. Rogerson, 1978 [Family: Dothideomycetes incertae sedis]
• Catulus Garman (ex Valmont), 1913 accepted as Scyliorhinus Blainville, 1816 [Family: Scyliorhinidae]
• Catulus Smith, 1838 accepted as Scyliorhinus Blainville, 1816 [Family: Scyliorhinidae]
• Catulus Valmont de Bomare, 1764 accepted as Scyliorhinus Blainville, 1816 [Family: Scyliorhinidae]
• Cepolus Duméril, 1805 accepted as Cepola Linnaeus, 1764
• Cirulus von Bredow, 1837 (uncertain)
• Citulus Griffith in Cuvier, 1835 accepted as Pseudocaranx Bleeker, 1863
• Conulus Fitzinger, 1833 † (unaccepted) [Family: Mollusca (awaiting allocation)]
• Conulus Gistl, 1848 † accepted as Galerites Lamarck, 1801 † [Family: Galeritidae]
• Conulus Küster in Martini & Chemnitz, 1844 (uncertain) [Family: Mollusca (awaiting allocation)]
• Conulus Leske, 1778 † [Family: Conulidae]
• Conulus Nardo, 1841 accepted as Calliostoma Swainson, 1840 [Family: Calliostomatidae]
• Conulus Rafinesque, 1815 accepted as Conus Linnaeus, 1758 [Family: Conidae]
• Copelus Provancher, 1881 (uncertain)
• Coprulus Mayer, 1952
• Cucullus Quoy & Gaimard in de Blainville, 1830 (uncertain) [Family: Cnidaria (awaiting allocation), Phylum: Cnidaria]
• Cucullus Röding, 1798 accepted as Conus Linnaeus, 1758 [Family: Conidae, Phylum: Mollusca]
• Cucullus Steiner, 1994 † [Family: , Phylum: Animalia incertae sedis]
• Cucullus Zeder, 1803 accepted as Cucullanus Müller, 1777 [Family: Cucullanidae, Phylum: Nematoda]
• Cuculus (unaccepted > nomen nudum) [Family: Triglidae]
• Cuculus Lesson, 1843 (uncertain) [Family: Cnidaria (awaiting allocation)]
• Cuculus Linnaeus, 1758 [Family: Cuculidae]
• Cullus Shimanskii, 1968 † (uncertain)
• Culmulus Uvarov, 1953
• Cuphus Agassiz, 1846 accepted as Kuphus Guettard, 1770
• Lupulus de Blainville, 1843 (uncertain) [Family: Mammalia (awaiting allocation)]
• Lupulus Gervais, 1855 accepted as Canis Linnaeus, 1758 [Family: Canidae]
• Lupulus O. Kuntze, 1891 (unaccepted) [Family: Rhamnaceae]
• Lupulus P. Miller, 1754 accepted as Humulus Linnaeus, 1753 [Family: Cannabaceae]
• Lupulus Trouessart, 1897 accepted as Lycalopex Burmeister, 1854 [Family: Canidae]