Cut upon Regeneration in Gunda ulvse. 



363 



eoc.c. 



Fig. VIII. — Section through Headless Form, 62 days (text-fig. Ill, 6). ex.c, excretory 

 canals ; g., gut ; n.c, nerve cords ; pa.c, parenchyma cells ; p.c, pigment cells. 



Fig. IX. — Section through Heteromorphic Head, 20 days (text-fig. IV, 8). e., eye ; g., gut ; 

 ga., ganglion : Ojp.n., optic nerve ; pa.c, parenchyma cells. 



IV. Discussion. 



As was mentioned earlier in the paper, Child (1) has already shown 

 that the presence of at least half the cerebral ganglia is necessary for 

 complete regeneration in Zeptoplana. The removal of more than half 



VOL. LXXXVII. — B. 2 E 



