6 



ART. 17. — N. YATSU. 



IDÜidiii developed from the three lots. Yet in the experiments 

 eggs kept unfertilized over three hours were not employed. 



II. Results of Experiments. 



Series A. Removal Experiments at the Metaphase of the 



First Maturation Mitosis, the Nucleated Fragment 



being fertilized at three Different Periods. 



Fig. 2. 



A large portion of cytoplasm was cut 

 off from the unfertilized egg at the meta- 

 phase of the first maturation mitosis. In 

 most cases the cut was made obliquely so 

 as to disturb as much as possible the organ 

 bases, if any (Fig. 2). Nucleated fragments 

 were fertilized at three different periods, 

 i. e., one, three and five hours after the 



Diagram showing the 

 0[)eration in Series A, operation. 



the part removed being Sixty-five pilidia w^ere produced and 



the results may be tabulated as follows : 



1 h. 

 Perfect , 68.2? 



70 



Defective.., 31.8?^ 



3 hs. 



65.3?/^ 



34.7^/. 



5 h<. 



75 9ö 

 25 fo 



If the localization of organ bases progresses during this 

 period one would naturally expect more defective larvœ in the 

 lot which was fertilized last than in the other two. But the 

 inconstant percentage of the above table may be taken as clearly 

 showing that during the first five hours at least there takes place 

 no 23erceptible progress of germinal localization in the nucleated 

 fragments. This conclusion is important not only in itself, but 



