Development of Paramphistomum sukari Dinnik, 1954 (Trematoda: Paramphistomidae) in a snail host

The development of Paramphistomum sukari Dinnik in a snail host is described with the emphasis laid on the succession of redial generation.The sporocyst gives birth to about twenty to thirty rediae. These rediae of the first generation commence with the production of daughter rediae then enter the second phase of their productivity during which they produce cercariae. The daughter rediae, or the rediae of the second generation, repeat these two phases during their lives, commencing with redial production and after that changing to the production to cercariae. Both the first- and second-generation rediae are able to produce a few daughter rediae at the end of their life. There is evidence that the subsequent generations of rediae are also able to give birth to daughter rediae and cercariae.As a result the successive generations of rediae maintain the infection in an intermediate host for a long time, probably as long as the infected snail can survive.