24 ART. 3. S. IKEDA : CONTRIBUTIONS 



about 10°. When seen at 7:30 next morning (the 4th day), the 

 general outline of the embryonic body with the well defined 

 neural groove and folds was already established. The posterior 

 end of the neural groove at the time was about 25° below the 

 equator showing that the spot which was the dorsal blastoporic 

 lip must have returned, as in the first egg (Egg C), nearly to its 

 starting point, after the blastopore was completely closed. 



Egg H was therefore like Egg C in the mode of the 

 blastopore closure, and in the location of the embryo. But the 

 spot at which the dorsal blastoporic lip first appeared was much 

 lower down than in the egg first observed, and was closed much 

 earlier, while the arc travelled bv the whole egs; m its rotation 



' J Ou 



was less, being about 60°. 



Egg J was taken out from a mass obtained on the morning 

 of May 20th. The eggs were all in the first cleavage, but I 

 again failed in my attempt to observe the relation of that plane 

 to the future embryo, as an egg of that stage on being fixed on 

 the mirror showed signs of abnormalities. So, Egg J was fixed 

 on the mirror the next morning. At 9:50 a.m., of the same day 

 (May 21th.), the dorsal blastopore lip made its first appearance 

 at a spot about 12° below the equator. The left, and right side 

 views of the egg were to be seen respectively at 160° and 340° 

 (=100+180) of the rotating dish, while the posterior view was 

 at 250° ( = 160 + 90). When seen about ten minutes later (10 

 a.m.), the dorsal lip had grown about 6° downwards, and at 

 2 p.m., about 9° further down. Thirty minutes later (2:30 p.m.), 

 in the left side view the dorsal lip had grown down another 9°, so 

 that the lip had moved downwards over the yolk altogether about 

 24° in 4 hours and 40 minutes. The rate of growth was not con- 



