16 



ART. 17. — N. YATSU. 



Fig. 13. 



Diagram showing 

 section planes in 

 Series J. 



a-cut perfect 10 defective 4 

 b-cut ,, „ 1 



c-cut ,,8 ,,0 



From the above table it will be seen 

 that the larvœ are very slightly affected by 

 the section as in Series E, provided, of 

 course, the portion removed be not consider- 

 ably large. How much cytoplasm can be 

 taken off without causing noticeable effect 

 I did not determine. 



Series K. Kemoval Experiment at the 2-cell Stage. 



Both the blastomeres were cut horizontally at the 2-cell stage 

 along three different levels (Fig. 14, A a. b. c). Ten larvce were 

 derived from the operation. 



a-cut 3 perfect. 



b-cut 3 defective in gut or anenterion (Fig. 14. b, B; c, C). 



c-cut 4 perfect. 



b 



Fig. 14. 



A, diagram showing the cutting planes in Series K ; B, pilidiura arising 

 from the egg operated upon as in b ; C, anenterion from c. 



