INDUCTION OF A FURROW-LIKE DENT ON THE SURFACE OF THE NEWT EGG BEFORE THE ONSET OF CLEAVAGE.

Sawai (2) found in the amphibian egg that furrow-inducing cytoplasmic component (FIC) was localized along the cleavage furrow, which could induce a furrow on the polar surface of cleaving egg under which FIC was injected. But this procedure failed on the surface of uncleaved fertilized egg. In the present experiments, an attempt was made to induce a cleavage furrow on the surface of uncleaved egg of the newt, Cynops pyrrhogaster. A piece of the cortex was cut from the uncleaved egg, which was transplanted to the egg just before or just after the onset of the cleavage, using a fine glass needle. After the transplantation FIC was injected beneath the graft with a capillary. The graft reacted to FIC and a furrow-like dent was induced at the position. Besides, stiffness of the graft increased during the cleavage of the host egg. In contrast to the cortical grafting, a large amount of the cytoplasm excluding FIC was injected under the cortex of an uncleaved egg. After several minutes FIC was deposited at the site. A furrow-like dent was formed there in many cases.