Abstract: Electronic microscopy showed that the egg-shell of E. ver micularis is composed of 6 layers, namely, surface membrane, external uterine layer, internal uterine layer, vitelline layer, chitinous layer and lipid laycr. The surface membrane, external uterine layer, vitelline layer and lipid layer are thin membranes(Fig. 1). The internal uterine layer is thick within which numerous regularly arranged long fibrous substances run radially and, many long or short slits scattered between them. These slits communicated with the micropores on the shell surface, and lined both by the surface membrane and the external uterine layer (Figs. 2-4). The constructional features of the internal uterine layer of E. vermicularis cggshell is considered to be species specific.