sporocyst /spôr″əsist/ [Gk, sporos + kystis, bag] , 1. any structure containing spores or reproductive cells. 2. a saclike structure, or oocyst, secreted by the zygote of certain protists before sporozoite formation. 3. the second larval stage in the life cycle of parasitic flukes. The saclike organism develops from the miracidium, or first larval stage, in the body of a freshwater snail host and contains germinal cells that give rise either to daughter sporocysts that develop into cercariae or to rediae. See also fluke.
