236 W. M. SMALLWOOD. 



EXPLANATION OF PLATE II. 



FIG. 8. Is taken from one of the cells shown in Fig. 9. The vacuolated condi- 

 tion of the cytoplasm is shown in the clear spaces. The spindle is in the anaphase 

 and so directed as to set a cell free in the segmentation cavity. There is a large cen- 

 trosphere at each pole. 



FIG. 9. Outline drawings of embryo. Numerous vacuoles are present in the cells. 

 Seg. cav, segmentation cavity. 



FIGS. 10 to 29 are from Pennaria. 



FIG. lo. Telophase second maturation. Egg in medusa. Cl. pol. i, first polar 

 body ; cl. pol. 2, second polar body. 



FIG. n. Female pronucleus drawn from an egg before deposition. Pronl. 9> 

 female pronucleus. 



FIGS. 12 to 1 8 show the migration of the chromatin from the pronuclei into the 

 cytoplasm. Pronl. 9 > female pronucleus ; < , male pronucleus. 



