TENTACLES 



Li 



TENTACLES 



AMPUTATION 



J O-BASE 



BLASTEMA FORMS 



BLASTEMA DIFFERENTIATES 



/^S— BASE 

 HfOROID 



SALAMANOER 



FROG 



Fig. 156. Variations in the regenerative capacities of three different organ- 

 isms. Left: Total regeneration in hydroids. Every part will regenerate into a 

 whole individual. Center: Limited regeneration in salamanders. A limb is ampu- 

 tated and, after healing, a blastema forms which differentiates into the missing 

 part. Right: The frog limb stump heals but no blastema forms and no regenera- 

 tion occurs. What is the difference between the frog limb and the salamander 

 limb that the former does not regenerate while the latter does ? 



232 



