Abstract
In the egg of the eel, Anguilla japonica, the peripheral periblast may be recognized as early as the one cell stage, while the subgerminal periblast is discernible for the first time at the blastula stage.The periblast nucleus seems to be derived from the nuclei of both the marginal cell and bottom cell of the blastoderm.The nuclei of the periblast increase in number by mitotic division until the end of the blastula stage, thereafter they multiply by amitosis.Thus, the periblast becomes a syncytial layer enclosing the whole yolk sphere until the late stage of gastrula.The periblast does not take part in the formation of a permanent embryonic body, but it supposedly takes on some important role in the consumption of yolk.
