210 



H. SAXTON BURR 



medialis. At tliis time the new telen('0])halon is similar in or- 

 ganization to its follow but it is considerably smaller in size. 

 From tliis tiiiu^ on •growth and differentiation continue in both 

 hemispheres hi an entirely normal fashion, though apparently 

 there is to some extent a compensating increase in the rate of 

 growth of the ncnv t(4encephal(m foi- in tlu^ oldest larva of the 



Fig. 4 Transverse section of an embryo one and one-half months after the 

 operation showing the regenerating telencephalon as a result of the presence of 

 the nasal placode. X 44. 



series, a larva some three and a half months old, the new hemi- 

 sphere had completely regenerated and could not be in any way 

 differentiated from its fellow. 



SUMMARY 



It is evident from the above experiments that the forebrain 

 of Amblystoma will not regenerate when it and its functional 

 end organ are completely extirpated. The healing of the wound 



