Paramphistomum daubneyi sp.nov., recovered from Bos taurus in Kenya, East Africa, is described and differentiated from the other species of the genus possessing a Microbothrium type of genital atrium.Lymnaea truncatula Müller was infected experimentally with miracidia of P. daubneyi and the development in the snail host is briefly described.
Experiments on the larval development of Fasciola gigantica carried out under natural conditions have shown that at temperatures of 16° C. or less the rediae did not produce cercariae. The first-generation rediae, developed from the sporocyst, and all the rediae of subsequent generations produced only daughter rediae and did not change over to the production of cercariae as long as the low temperatures of the cold season lasted.As soon as the cold season ended and the temperature of the water in the aquaria containing the infected snails rose to a mean maximum of 20° C. all the rediae switched from redial to cercarial production.
A study of several samples of young conical flukes reared from metacercariae obtained by the late Dr. P. L. LeRoux from certain fresh water snails has resulted in the following findings.It appears that the species which caused the severe intestinal paramphistomiasis amongst sheep described by LeRoux (1930) in South Africa was Paramphistomum microbothrium Fischoeder, not Cotylophoron cotyhphorum (Fischoeder) as was thought at the time and subsequently repeated in all the text books and reviews on paramphistomiasis published afterwards.
The morphology of Paramphistomum sukumum sp.nov. from Bos indicus in the Lake Region of Tanganyika, East Africa, is described and illustrated.A list is given showing the incidence of nine species of the family Paramphistomatidae and three species of the family Gastrothylacidae found in cattle in the Sukumaland area of the Lake Region of Tanganyika.
(1)Paramphistomum phillerouxi sp.nov. from rumina of cattle in Northern Rhodesia is described and its morphology compared with that of Paramphistomum microbothrium Fischoeder from Egypt, Kenya, Northern Rhodesia, and South Africa.(2)Bulinus forskalii (Ehrenberg) is a natural intermediate host of P. phillerouxi in Northern Rhodesia and Tanganyika. Of other snails, Bulinus senegalensis (Muller) from Gambia was successfully infected experimentally, and Bulinus cernicus (Morelet) in Mauritius was found naturally infected with P. phillerouxi.(3) The development of P. phillerouxi in Bitlinus forskalii is described. The sporocyst gives birth to 18 to 28 rediae. These firstgeneration rediae are able to produce daughter rediae as well as cercariae. It seemed that not all of the first-generation rediae started to produce daughter rediae first. Some of the rediae began by producing cercariae and produced a few daughter rediae later alongside numerous cercariae. There is some evidence that the subsequent generations of rediae are also capable of developing daughter rediae and cercariae simultaneously.(4) The first young cercariae to leave the parent rediae were observed 21 days after exposure of the snails to a single miracidium each, and the first shedding of mature cercariae was noted 42 days after the exposure, the snails being kept at 20°C.
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