Trematodes of Indian fishes. Part - 4 four new genera, one new subfamily and one new species, with a review of the species of Ophiocorchis Srivastava, 1933 , (family - Hemiuridae Luhe, 1901). Proceedings of the National Academy of Sciences India Section B (Biological Sciences), 48(1) 1978: 39-52. 39 [Zoological Record Volume 117]