THE OETENTATION OF THE FROG'S EGG. 



379 



pole of different eggs. The line m n represents the first furrow, 

 and a, b, c, d, the four cells formed by the first and second 

 segmentation furrows. In Fig. a the dotted line 3e y passes 

 through the centre of the crescent-shaped pigmented area^ and 

 divides the egg symmetrically. The first furrow lies to the 

 right of it. 



ElG. B. 



In 30 cases out of 119 the second furrow seemed to divide 

 the pigment more equally (see Fig. b), and the second furrow 

 is a little to the left of the imaginary line of symmetry x y. 



In the remaining 13 cases the pigment seemed to extend 

 as much on one side as on the other, and the line x y 



