The family Ceramoporidae and the Ordovician genera Crepipora Ulrich, Ceramoporella Ulrich, and Ceramophylla Ulrich are redefined. The new Ordovician genus Acanthoceramoporella is included in the family. Cheiloporella Ulrich is placed in synonymy with Ceramoporella. Several Ordovician species formerly included in Coeloclema Ulrich are reassigned to Ceramophylla. The microstructure of the lunarial deposit in genera of Ceramoporidae closely resembles that of some Mesozoic and Cenozoic Lichenoporidae. The order Cystoporata probably should be expanded to include thelichenoporoid cyclostomes.