Cut upon Regeneration in Gunda ulvafi. 



359 



C. Anterior Regeneration. 



Anterior regeneration in animals cut anteriorly to the cerebral ganglia is 

 quite complete (text-fig. Ill, 1-3). In cases, however, where the cut takes 

 away more than about one-third of the ganglia, it is only partial. Forms 

 with either two eyes or one are produced, the auricles in the latter case 

 being fused (figs. 4 and 5). In animals cut behind the cerebral ganglia 



Fig. III. 



1. Fragment BBP, 14 days ; 2. Ditto, 28 days ; 3. Ditto, 41 days. 4. Fragment CCP, 

 41 and 62 days. 5. Fragment CCP, 41 and 62 days. 6. Fragment DDP, 41 and 

 62 days. 



no head formation ever occurs. These posterior pieces showed some change 

 of form, as forward growth caused them to become helmet shaped (fig. 6). 

 After two months these pieces still remained without any attempt at regenera- 

 tion of the head. 



A number of headless pieces and defective heads were sectioned for 

 examination of the nervous system, and the sections are shown. 



