THE BIOLOGY OF THE CELL SURFACE 













Fig. 37. — Egg of Nereis with first maturation spindle held near the centre of the 

 cell as an effect of ultra-violet irradiation. 





0# 





♦»• 



^ -4$ ^• 



^•'^# 



^ 1 



■■■■■ ♦./•/ 



Hi..''; 



*?^ ti^ 



Fig. 38. — Irradiated egg of Nereis showing nuclear division without extrusion of 



polar bodies. 



342 



