The Cellular Basis 



143 



IPS. 



Fig. 46. Sections of the Egg of Stycla, showing maturation, fertiliza- 

 tion and early cleavage. / PS., First polar spindle, p.b., Polar bodies ; 

 $N, sperm nucleus, $>iV, egg nucleus. />./., peripheral layer of yellow pro- 

 toplasm. Cr., Crescent of yellow protoplasm. A.-, ./, Anterior cells, 

 B 3 , B 3 Posterior cells of the 4-cell stage. In 1 the sperm nucleus and cen- 



