74 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



has, therefore, nothing to do with the activation of the egg. 

 The question arises : What is its function ? 



We receive an answer to this question when we observe 

 what becomes of the eggs at room temperature after the 



Fig. 19 Fig. 20 



FIGS. 19 and 20. Beginning of the process of disintegration after the arti- 

 ficial membrane formation in the egg of S. purpuratus. Small droplets appear at 

 the equator of the elongated egg. 



membran3 formation. In this case the centrosomes and two 

 astrospheres are formed and the nucleus may divide, but then a 

 process of disintegration begins in the egg. Small droplets 

 appear usually on one side of the egg (Figs. 19, 20). One gains 

 the impression that these droplets begin to be extruded at the 



Fig. 21 Fig. 22 



FIGS. 21 and 22. Eggs of the same lot, showing more plainly that the droplet 

 formation and disintegration begin in the plane of cell-division. 



time of the first cell division. This is obvious from Figs. 

 21 and 22, where the droplets appear in the plane of segmenta- 

 tion. In Figs. 19 and 20 they appear in the equatorial plane 

 of eggs which are not segmented, but which show the elonga- 

 tion in the direction of the two poles. 



