H. V. BR0NDSTED 



b a 



Figure 14. Bdellocephala. The segment a was trans- 

 planted to b with reversed polarity ; after severe wound 

 closing two transverse cuts were made through the chimera; 

 a regenerated a head with rate and polarity characteristic 

 of the portion. 



I therefore asked some questions of this planarian, using a rather crude mode of inter- 

 rogation. I made a cut in the median line of the animals and — after removing the 

 protruding pharynxes — immediately reunited the two halves in such a way that 

 they were shifted along the longitudinal axis. After a few days the two halves had 

 healed together, and the animal was then decapitated by a transverse cut. The 





>:. 



Figure 15. Planaria lugnbris. 

 Two halves were reunited with 

 a slight shift. A transverse cut 

 was made through the fields as 

 indicated in the left figure. The 

 right figure shows the resulting 

 normal animal; only the right 

 eye is slightly bigger. 



128 



