Comparison of shell and appendage morphology between the South African Megalocypris Sars, 1898 and the North American Cypriconcha Sars, 1926 indicates that the genera are congeneric, with Megalocypris having priority. The genera Herpetocypris Brady and Norman, 1889 and Stenocypris Sars, 1889 are morphologically closely related to Megalocypris. There are five South African and six North American species belonging to the genus, including a new Canadian form, Megalocypris pseudoingens n. sp.