Seven adult schistosome species were recovered in Manitoba from 431 birds and 34 mammals examined. Seven species of schistosome cercariae were also found. One new adult species, one new larval species and two new larval varieties were described. A number of new host and locality records were reported. The seasonal incidence of two cercarial species and the growth pattern of their host were determined. A monograph on the known schistosomes of the world was prepared. This includes the complete systematics of the Family together with the descriptions of all known species and taxonomic keys.