18 AßT. o. — S. 1KEDA I CONTRIBUTIONS 



to errors. One or more accessory apparatuses specially designed 

 for the purpose may be necessary to accomplish this object. 



I should like to add here that my observations thus far 

 have determined the feet that all the eggs within the vitelline 

 membrane of Rhacophorus as well as of other Amphibians studied 

 by me are in their earliest stages incapable of executing any 

 horizontal movements around the vertical axis, if they are care- 

 fully placed in their natural position : 



Having premised these remarks, I may now proceed to 

 describe the eggs observed. I begin with Rhacophorus. 



An egg-mass of that animal was obtaineel at 10 a.m., April 

 27th. It had probably been deposited during the preceding night. 

 From it an egg (Egg C, Figs. 20-38) was taken out and fixed 

 on the mirror by the gelatine method at 2:2ö p.m., on the same 

 day. It had already gone through the earlier phases of segment- 

 ation : cell-outlines were visible on its upper hemisphere, while 

 obscure on its lower half (Fig. 20). At 2 p.m., on the next day 

 (April 28th), the first trace of the dorsal blastopore lip had ap- 

 peared at about 6° below the equator (Fig. 21). The posterior 

 view of the egg (Fig. 21) was seen at 217° of the rotating mirror- 

 dish. At 130° and 310° (217-90 = 127; 217 + 90=307), were 

 respectively the right, and left side views. Fig. 23 gives the 

 left side view sketched at 3:20 p.m., on the same day : the middle 

 point of the dorsal lip has moved slightly downward and its limbs 

 have grown longer. Fig. 22 gives a view of the upper hemisphere, 

 of the egg seen from above at 2:30 p.m. The large translucent 

 area of the segmentation-cavity is found occupying the centre of 

 the egg-outline. On that day, the blastopore lips did not quite 

 encircle the lower hemisphere but on the next morning (April 



