It has been reported that the follicular wall of the growing oocyte in bony fish ovariescontain a zona pellucida.This zona material is formed between the oocyte surface andthe follicular epithelium during the development of the follicle and consists of carbohy-drates and proteins.The present investigation has been carried out with zona materials froma fresh-water fish,Anistichthys nobilis(Richardson),to determine their immunologicalproperties and antifertility effect on mammals.Female rabbits were immunized...