Organisms from Eggs 



131 



Fig. 10 



tration and probably the more so the greater the dis- 

 tance from B; and the same may probably be said for 

 the substances determin- 

 ing mesenchyme and 

 ectoderm formation. 

 Hence the unfertilized 

 egg contains already a 

 rough preformation of 

 the embryo inasmuch as 

 the main axis of the em- 

 bryo and the arrange- 

 ment of its first organs 

 are determined. 



After the egg is fertilized the cell divisions begin. 

 The first division is as a rule at right angles to the 



stratification of the 

 egg, each of the two 

 cells contains one-half 

 of the pigment ring 

 (and of each of A and 

 C) (Fig. 10), and after 

 the next division each 

 contains one-fourth of 

 the pigmented part. 

 Each of the four cells 

 is a diminutive whole 

 egg since each contains 

 the three layers in the normal arrangement (Fig. 11). 



Fig. 11 



