Helminth parasites of fishes from the Arabian Gulf. 6. On three species of digenetic trematodes: Prosorhynchus epinepheli Yamaguti, 1939; Paraproctotrema qatarensis n. sp. and Prosorchis breviformis Srivastava, 1936. Rivista di Parassitologia, 49(1) 1989: 79-85. i [Zoological Record Volume 126]