[Sequence of reconversion of the sporocysts of Schistosoma mansoni producing cercariae, to the production of new generations of sporocysts (author's transl)].

During the life cycle of Schistosoma mansoni the production of sporocysts of a higher order than secondary is a normal mode of larval multiplication which intervenes in asexual reproduction of the parasite. The sequence of reconversion of sporocysts producing cercariae to those producing sporocysts III, IV, etc... can be divided into three principal steps: (1) cessation of cercariae production; (2) degeneration of cercariae contained in the sporocyst, and (3) production of the new generation of sporocysts. Degeneration of intrasporocystic larval material seems to be an indispensable step for the new orientation of production. The signifance of this method os multiplication in the ecology of transmission is discussed.