Localization of the Nemertine Egg. 



301 



Diagram of the egg just after removal from the animal, showing germinal 

 vesicle and basal protuberance. HH, VV, and OO indicate, respectively, the 

 directions of the horizontal, vertical and oblique cuts. 



Fig. 4 (x 216). 



Cleavage of Fragments of the Unfertilized Egg. 



A, eight-cell stage, from nucleated fragment (r=4/5 of egg), obtained by a 

 horizontal cut; viewed from lower pole. B, sixteen-cell stage, from non- 

 nucleated fragment (^3/5 of egg), obtained by a horizontal cut; side view. 

 C, seven-cell embryo, from non-nucleated fragment (=2/5 of egg), obtained 

 by a vertical cut; viewed from convex side. 



