The cleanage-canly begins with the tenth section and ends with the sixtieth. 



The periblast is thicker under the apex than at the opposite point. 



Section sixty is much thinner than section five (both are at the boundary of the cleavage- 

 cavity or at a point where the lower layer begins to be distinct from the upper layer). 



The periblast plainly does not contribute elements to the ring; it is more difficult to decide 

 about the axial portion. In some sections, notably in the axial portion, I find cells sometimes 

 more or less delimited in the periblast (3rd, 5th, 6th, 8th). This delimitation does not, how- 

 ever, show that periblast cells pass into the cap, as such are visible at certain stages of the 

 nuclear transformations. I am inclined to think — not certain — that the periblast does not 

 enter into the ring at any point. 



