66 J. T. PATTERSON. 



PLATE II. 



FIG. 7. Early prophase of first maturation. The black body close to germinal 

 vesicle is the nucleolus. X 1,240. 



FIG. 8. Late anaphase of first maturation. The sperm was drawn in from the 

 next section to the left in the series. X 1,240. 



FIG. 9. First maturation spindle. Xi,827. 



FIG. 10. First polar body chromosomes above, and chromosomes of the second 

 oocyte below. X 1,827. 



FIG. ii. Anaphase stage of first polar body above, and chromosomes of second 

 o5cyte below. X 1,827. 



FIG. 12. Anaphase stages of the first polar body above, and second- maturation 

 below. Xi,240. 



FIG. 13. Very early stage of the pronuclei, female above, male below. Note 

 tiny aster lying between them. X 1,240. 



FIG. 14. Fusion of male and female pronuclei. X 1,240. 



FIG. 15. Pronuclei, male above, female below. X 1,240. 



FIG. 16. Conjugated nucleus. X 1,240. 



FIG. 17. Polar view of first cleavage spindle, showing sixteen chromosomes. 

 Xi,827. 



FIG. 1 8. Side view of cleavage spindle of one of the first four cells. There are 

 fifteen chromosomes in each daughter group. The sixteenth chromosome, which 

 has just divided, lies on right side of spindle. X 1,827. 



