ALLEN. 



EXPLANATION OF PLATE III. 



FIGS. 2, 6 x 115 ; FIGS, i, 3-5, 7 x 152. 



FIG. i. Young ovum showing three nuclei (ti). /i l in the process of division. 

 No segmentation planes visible ; a, nuclei of absorbed cells. 



FIGS. 2, 3. Slightly later stages ; segmentation planes well marked. , nuclei ; 

 a, nuclei of absorbed cells. 



FIG. 4. Still later stage of segmentation. 



FIG. 5. Section through an egg containing fifteen or sixteen nuclei, but no 

 well-defined cell walls. , nuclei ; a, nuclei of absorbed cells. 



FIG. 6. Later stage ; cell boundaries indefinite. 



FIG. 7. Advanced stage of segmentation ; cells irregular in outline, cytoplasm 

 very reticular ; , nucleus ; n l , nuclei in process of division ; a, nuclei of absorbed 

 cells. 



