• Conaperta Antonius, 1968
• Conferva Linnaeus, 1753 (uncertain > nomen dubium)
• Confervea O.F. Muller, 1783 (uncertain > nomen dubium)
• Conflata Schmidt, 1912 (uncertain)
• Congeria Dollfus, 1942 [Family: Tentaculariidae]
• Congeria Guiart, 1935 accepted as Nybelinia Poche, 1926 [Family: Tentaculariidae]
• Congeria Partsch, 1835 [Family: Dreissenidae]
• Coniesta Hampson, 1919
• Conifera Reynolds, 1978 † accepted as Coniferina Reynolds, 1978 †
• Contexta Jordan, 1902 accepted as Mauia Blackburn in Blackburn & Sharp, 1885 [Family: Anthribidae]
• Contexta M.B. Gnilovskaja, 1972 † [Family: Moniliporellaceae]
• Contorta Megerle in Villa, 1841 (uncertain)