A description of Zalophotrema hepaticum is presented. Study of this species and review of the literature show that the genera assigned to the two families, Fasciolopsidae and Campulidae, may be included in a single family. Furthermore, since Fasciola is the nomenclatorial type of the family to which it belongs, the rules of nomenclature do not permit the substitution of the name Fasciolopsidae for Fasciolidae. Consequently the family Fasciolidae is restored with three sub-families, Fasciolinae, Fasciolopsinae, and Campulinae. A new genus, Synthesium, is erected to contain Distomum tursionis Marchi.