[spo.ro.cyst] n [ISV] (1861) 1: a case or cyst secreted by some sporozoans preliminary to sporogony; also: a sporozoan encysted in such a case
2: a saccular body that is the first asexual reproductive form of a digenetic trematode, develops from a miracidium, and buds off cells from its inner surface which develop into rediae