In small samples of the siganid fishes Siganus rivulatus Forsskål et Niebuhr and S. luridus Rüppel (Teleostei) from off the Saudi coast of the Red Sea, some individuals of each fish were found infected with a new intestinal trematode. Those of S. rivulatus were infected with Hexangium saudii sp. n. (Trematoda: Microscaphidiidae), whereas those of S. luridus with Progyliauchen magnacetabulum sp....
