296 WATASE. 



EXPLANATION OF PLATE IX. 



Loligo Pealei. . 



All the figures in this plate have been magnified 45 diameters. 



Fig. I. Unsegmented ovum, with three polar globules, one of which has not been 

 made distinct by the engraver. The whitish cap at the pointed pole of the egg is the 

 germ-disc. 



Figs. 2-8. Different stages of cleavage. The eggs have been slightly tipped over 

 so as to show the cleavage field better. 



Figs. 9, 10, ix. Side views of more advanced stages of cleavage, showing the 

 relation of the marginal elongated cells to the yolk-mass and to the central smaller 

 cells. 



Figs. 12, 13, 14. Views from the cleavage-poles. 



Fig. 15. An abnormal specimen, with the germ-protoplasm at the side of the 

 ovum, and not at the top as is usual. Cleavage is, however, normal. 



