The development of the prothallia in nine species of Callipteris Bory (Woodsiaceae), four species of Diplazium, the genus from which Callipteris has been segregated, and one species of Dryoathyrium are studied in this paper. The data obtained are compared with the development of the prothallia of several other genera of Woodsiaceae. The main difference between Callipteris and the other genera of Woodsiaceae was that the antheridia dehiscence of Callipteris, occurs by an opercular cell and whereas some of Diplazium and other Woodsiaceae antheridia dehiscence occurs by a lateral or apical pore. The presence of antheridiogens is suspected on the basis of small ameristic male gametophytes in the cultures. Spore germination in Callipteris is Vittaria-type, prothallial development corresponds to Adiantum-type.