During the stay of the vessel "Ob" (Soviet Antarctic Expedition) at Colombo, May, 1957, the author received from Dr. C. H. Fernando some specimens of different species of fishes from Ceylon, preserved in formalin, as a present for the Zoological Institute (Academy of Sciences of the U.S.S.R.) New species of Monogenoidea have been found when examining the gills of the fishes received and the present paper deals with their description. The material was preserved in strong formalin which highly condensed the tissues of the parasites. Therefore the details of the anatomical structure in most of the specimens could not be recognized even by means of phase-contrasting equipment. So the description is confined almost exclusively to the chitinoid armature of the haptor and copulatory organ. The terms and the measurements used in this paper are the same as those used previously (Gussev, 1955).

Department of Fisheries, Fisheries Research Station, Ceylon now incorporated in: National Aquatic Resources Research and Development Agency, Sri Lanka