344 WHITMAN AND EVCLESHVMER. [Vor tit: 
may have on the direction of cleavage, and for determining the 
relation of the early cleavage planes to the median plane of 
20 






Cw 
the embryo. Dean (no. 3, p. 422) found “in the early stages of 
segmentation that the cleavage planes occurred in the normal 
way when the position of the egg was reversed.” This is true 


