Origin of Different Kinds of Adaptations 381 
dividual. The development of an antenna in place of an eye 
in the shrimp, when the eye stalk is cut off near its base, is 
another instance of the occurrence of a perfectly constant 
process, but one that is of no use to the organism. 
When we recall that in some organisms regeneration takes 
place in almost every part of the body, it does not seem 
possible that this power could have been acquired by selec- 
tion. And when we find that many internal organs regener- 
ate, that can rarely or never be injured without the animal 
perishing, it seems impossible that this can be ascribed to 
the principle of natural selection. 
It has also been found that if the first two cells of the 
egg of a number of animals, jellyfish, sea-urchins, salaman- 
ders, etc., be separated, each will produce an entire animal. 
In some of these cases it is inconceivable that the process 
could ever have been acquired through selection, because the 
cells themselves can be separated only by very special and 
artificial means. 
These, and other reasons, indicate with certainty that re- 
generation cannot be explained by the theory of natural 
selection. 
