PLATE 5 



EXPLAXATIOX OF FIGURES 



Figures 25-27 are explained on p. 394. 



28 Normal egg showing the usual distribution of cytoplasm and yolk and the 

 usual relative sizes of egg and sperm nuclei and spheres. 



29 (1088) Centrifuged 100 turns of hand machine; fixed 1 hour later. Cy- 

 toplasm lies at vegetal pole, and the sperm nucleus which lies in it is much 

 larger than the egg nucleus. 



30 (1125, 2) Centrifuged 10 minutes; fixed 1| hours later. The sperm 

 nucleus is immense owing to its position in the cytoplasm, the egg nucleus is 

 small owing to its position in the yolk. 



382 



