Neotropical Monogenea. 10. Omothecium, new genus (Dactylogyridae: Ancyrocephalinae) and two new species from the piranambu, Pinirampus pirinampu (Spix), (Siluriformes) in Brazil. Proceedings of the Biological Society of Washington, 100(1) 1987: 8-12. 12 [Zoological Record Volume 123]