Phyllobothrium delphini (Bosc, 1802) was recovered from 25 marine mammals representing 12 species in two orders from four geographical localities. Five new cyst morphotypes are described. Comparison of mean measurements of each morphotype with the others suggests that P. delphini may represent more than one species. New host records for P. delphini are reported for Tursiops gilli Dall, Pontoporia blainvillei Gervais, and Lagenodelphis hosei Fraser. An apical sucker is noted for the first time on Monorygma grimaldii.