Edmund B. JVilson. 



is the side of attachment in the ovary, is found to represent the 

 lower or vegetative hemisphere. 



Fig. I. 

 Cleavage, from living Eggs. 

 I, Outline of egg soon after release, in polar view, showing white polar area; 

 2, the same egg, 20 minutes later, after throwing off the membrane; 3, similar 

 egg, from the side ; 4, egg one hour after fertilization, with fertilization-mem- 

 branei and polar bodies; 5, beginning of the first cleavage, formation of the 

 polar lobe; 6, trefoil, i^ hours after fertilization; 7, resulting 2-cell stage; 

 8, beginning of second cleavage from the side, second polar lobe forming; 9, 

 second cleavage at its height. 



1 Accidentally omitted by engraver. 



