Browsing by Author "Ratnayake, W.E."
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Item A genetical study of some mutants of drosophila ananassae doleschallJayasinghe, J.A.S.; Ratnayake, W.E.Item Four new morphological mutants of Culex pipiens fatigans, Wiedemann (Culex quinquefasciatus, Say) from Sri Lanka(National Science Council:Colombo, 1980) Ekanayake, S.; Ratnayake, W.E.Item Implications of technological advances for human resource development(Natural Resources Energy Science Authority of Sri Lanka:Colombo, 1991) Ratnayake, W.E.Item Mutations and environmental mutagens(NARESA:Colombo; 77p, 1983) Ratnayake, W.E.Item Observation on the structure and life-cycle of the digenetic fish-trematode Transversotrema patialense (Soparkar)(University of Peradeniya. Peradeniya, 1964) Crusz, H.; Ratnayake, W.E.; Sathananthan, A.H.Progenetic, egg-laden metacercariae of the trematode Transversotrema patialense (Soparkae, 1924) (Digenea: Transversotrematidae) have been recovered from under the scales of the freshwater fish Ophicephalus bloch and Macopodus cupanus (Cuv. et Val.) Caught in Batalagoda, Ceylon. The fish O. punctatus , M. cuponus and Tilapia mossambica (Peters) have been infected in the laboratory with the cercariae of this trematode, emitted by snails of the species Melanoids tuberculata (Muller). Many of the mrtacercariae that developed under the scales of these fish had ripe eggs. Uninfested, laboratory-bred snails of the same species became infested with radiae and cercariae of T. patialense, after exposure to fish carrying the matacercariae. At no stage were the metacercariae found to be eneysted. The mature metacercariae has been more precisely observed and described.Item Technology of genetics(NARESA:Colombo, 1984) Ratnayake, W.E.