Further study of the embryonic development of Oreochromis niloticus (Cichlidae, Teleostei) using scanning electron microscopy

The chronology of development of Oreochromis niloticus embryos was examined by scanning electron microscopy (S.E.M.) and the external structures which evolved during the embryonic period were analysed. Twenty‐four stages of embryonic development of this fish at 25°C are described with emphasis on the cleavage phases and morphogenesis of external organs and tissues. Because the development of internal organs could not be observed under S.E.M., the necessary investigation was completed by light microscopy.