266 



MARGARET MORRIS HOSKINS. 



development. In the cleavage which occurs about three hours 

 after fertilization, one finds that the chromatin has returned to 

 the normal condition. The number of the chromosomes can no 

 longer be distinguished accurately, as they are small and crowded 



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FIG. i. Diagrams showing the nuclear .conditions and the chromosomes of 

 eggs heated at different periods. A, heated before fertilization (parthenogenetic); 

 B, heated after fertilization and maturation; C, heated after fertilization and 

 before maturation. 



