I9O CORA JIPSON BECKWITH. 



EXPLANATION OF PLATE II. 



Pennaria. Figs. 9 and 10, X 1,300. 

 Clava leptostyla. Figs, n to 13, X 1,300; Fig. 14, X 350. 



FIG. 9. Third or fourth cleavage spindle with " nuclear nest " passing 

 on to it to form the equatorial plate, one vesicle broken up into chromosomes. 

 Pennaria. 



FIG. 10. Polar view of a cleavage spindle showing a "nuclear nest" 

 as it is breaking up to form the equatorial plate, slightly later than the 

 above, some of the chromosomes already free in the cytoplasm. Pennaria. 



FIG. ii. Metaphase of first polar spindle of egg of Clava leptostyla. 



FIG. 12. Anaphase of the second polar spindle of egg of Clava leptostyla. 



FIG. 13. Female germ nucleus and polar bodies of egg of Clava leptostyla. 



FIG. 14. Egg of Clava leptostyla showing the first cleavage spindle. 



