518 



REGENERATION 



The Urodelea retain their powers of regeneration throughout life, hut to a iBsaer 

 degree after metamorphosis. The Anura, on the other hand, lose most of their regenerative 

 powers after metamorphosis. However, there is recent evidence (Butler, Eose, Schotte'', and 

 Singer) that even the Anuran appendage will exhibit some powers of regeneration providing 

 (Eose) the cut surface is continually irritated by hypertonlclty with NaCl, or (Butler, 

 Schotte', Harland and Singer) the connection of the appendage with the central nervous sys- 

 tem is not interrupted. Schotte and Butler (19^1) have demonstrated the regression of the 

 humerus in a denervated limb of Amblystoma. In fact, these investigators make the state- 

 ment that: "No blastema is ever established on a completely nerveless amputated limb." 



Auo.l6 



Regression of skeleton of fore- 

 limb (Amblystoma) following de- 

 nervation. (Total time 32 days) 



m c^ 



^~— i=a3!g:4^ 



( From Schotte' & Butler I9U1 : 

 Jour. Exp. Zool, 87:279) 



Oct. 7 



Regeneration of foot and digits of 

 Rana piplens pre-metaraorphlc tadpole 

 hlndllmb. Photo taken 24 days after 

 transverse cut made at shank level. 

 (P. Bernstein) 



