PLATE 3 



EXPLANATION OF FIGURES 



14 Nucleus of an egg 30 minutes after fertilization; spermatozoon loosening 

 its substance within the segmentation nucleus; uniform cytoplasmic radiation 

 around the segmentation nucleus; many small chromatic granules in the cyto- 

 plasm. 



15 Nuclei of eggs 40 minutes after fertilization. Chromatic substance of 

 the spermatozoon loosened and connected with the nucleolus of the female pro- 

 nucleus. 



16 Achromatic oval segmentation nucleus with two nucleoli at its poles and 

 small chromatin granules at its periphery; radiations around each pole of the 

 nucleus; many small chromatic granules in the cytoplasm. 



17 Nucleus of an egg 40 minutes after fertilization. Copulation of the two 

 pronuclei, the male pronucleus containing fully developed chromosomes. 



18 Nucleus of an egg 40 minutes after fertilization. Accumulation of the 

 chromatic granules around the segmentation nucleus, rare in fertilized eggs. 



19 Nucleus of an egg 40 minutes after fertilization. Outgrowing of filaments 

 from the chromatin granules and development of a chromatin net (next stage in 

 figure 28). 



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