26o 



IVATASE. 



[Vol. IV. 



I. 



II. 



III. 



IV. 



Polyphemus oculus : 



Figures I and // show the holoblastic cleavage of the summer eggs. 

 Figures III zx\^ IV show the meroblastic cleavage of the winter eggs. All from 

 unpublished drawings of Dr. C. Ishikawa. 



From Dr. Ishikawa's private communication, as well as from 

 the published account by Grobben,^ Weismann and Ishikawa,^ 



1 Grobben: Die Embryonalentwicklungvon'^\ova& rectirostris. Wiener Arbeiten, 

 Bd. II, 1879. 



2 Weismann and Ishikawa : Ueber die Bildung der Richtungskorper bei thierischen, 

 Eiern. Ber. d. naturf. Gesellsch. zu Freiburg, Bd. Ill, 1887, Heft i, Taf. I, II, 

 and III. Ibid.: Ueber die Paracopulationim Daphnidettei. Zoologische Jahrbiicher, 

 Bd. IV, 1889, Heft I, Taf. X, XI, XII, XIII. 



