(1) A larval form of digenetic trematode (fluke) that develops in the body of its molluscan intermediate host, usually a snail; the sporocyst forms a simple saclike structure with germinal cells that bud off internally and develop into other larval types that continue this process of larval multiplication (considered to be a form of polyembryony).miracidium, redia, cercaria. (2) A secondary cyst that develops within the oocyst of Coccidia, a group of sporozoans that includes many of the most important disease agents of domestic animals and fowl; the sporocyst develops from a sporoblast and produces within itself one or several sporozoites, the infective agents for infection and multiplication in the next host. [sporo- + G. kystis, bladder]