Abstract: In this article,we present the observations of the ova of Taenidae which retain,as seen under scanning electron microscope,the premature ova of the Taeniarhynchus saginatus.An ovum comprises seven layers,which actually interpenetrate and interplay as a complete system.When the ovum becomes mature the capsule breaks,the yolk cells and the vitelline membrane udergo degenerative changes,but the embryophore and the hexocanth embryo grow into completion.Many detail descriptions have been made at home and abroad of the ultrastructure of the mature ova of Taeniidae (Inatomi,S.1962;Ishii,Y.1972;Wang Song-Shan and others 1980).These reports lay particular emphasis on the research of the embryophore s ultrastructure,as the embryophore s tubular system has specieal importance to our understanding of the physiology of the ova.Our researches,we study the ova of Taeniidae at an earlier stage,investigate its basic structure and ultrastructural changes in its development.It may help us further understand this new problem.