276 MARGARET MORRIS HOSKINS. 



EXPLANATION OF PLATE II. 



FIGS. 6, 7, 8, 9. Equatorial plates of first cleavage of eggs, heated immediately 

 after insemination (triploid). 



FIGS. 10, ii. Chromosomes from first cleavage of normal eggs. 



FIG. 12. Chromosomes from first cleavage of dispermic egg. 



FIG. 13, 14. Equatorial plates of first cleavage of parthenogenetic eggs (diploid). 



FIGS. 15, 1 6, 17. Equatorial plates of first cleavage of eggs heated after matura- 

 tion was completed (diploid). 



FIG. 18. Chromosomes from an egg heated immediately after insemination. 

 Egg preserved three hours after fertilization. 



FIG. 19. Chromosomes from a normal egg, preserved three hours after fertiliza- 

 tion. 



FIG. 20. Chromosomes from an egg heated after maturation was completed. 

 Egg preserved three hours after fertilization. 



FIG. 21. First cleavage (anaphase) of an egg heated after maturation was 

 completed. 



