This paper presents the results of observation on oogenesis of Tilapia mossambica by SEM with DMSO freeze-cracking method

The yolk globules first appear around the nucleus of oocyte and progressively occupy the most of the cytoplasm of mature oocyte. The chorion(or zona radiata) is be lieved to be formed by the oocyte. Therefore

the egg membrane is classified as a primary envelope. It is confirmed that there are two layers of ceils at the periphery of the primary oocyte

that is

granulosa cell layer and theca cell layer.