12 



ART. 17. — N. YATSU. 



a-cut 



b-cut 

 c-cut 



r 2 perfect, 

 lidia { 



( 1 defective iu tlie lappets. 



. . . r 4 



G pi lidia < 



4 perfect, 

 defective. 



4 pilidia { all perfect. 



Fig. s. 



A, pilidium which arose 

 from the egg operated on 

 as in a. 



Though the number of operations 

 was not large enough to make it possible 

 to draw any definite conclusion, yet it 

 seems to show that the cuts do not 

 greatly affect the subsequent morphogenic 

 processes. It might be mentioned here 

 that as I have described elsewhere ('10 

 p. 4) cleavage always takes place ab- 

 normally in the eggs operated on as in 

 this series. 



One case which seems to be worth 

 mentioning is a perfect pilidium (Fig. 

 8. A) derived from an egg the animal 

 portion of which had been cut off as in 

 Fig. 8. a. 



Series F. Removal Experiment performed during the First Cleavage, 

 the Cytoplasm being cut off from both the Elastomeres. 



During the first cleavage the eggs were cut in three difïëreut 

 ways as in Fig. 9. 



From the fragments operated on I was able to rear nineteen 

 larvte, which may be classified as follows : 



