Curious Creatures 



21 I 



tible portions often work their way through the in- 

 testinal wall and out of the body; but this is in no wise 

 disconcerting to the nemertean, as the punctures heal 

 rapidly, leaving it no worse for the experience. 



All nemerteans have the power to regenerate lost 

 parts, which enables them to undergo astonishing in- 

 juries without fatal results. They can be cut completely 

 in two, and the fore body will ultimately grow into a 



meckelia; the ribbon worm, with proboscis partly extruded, 



new and perfect worm, while the hind body will retain 

 its vitality for days before dying. This division of the 

 body can be accomplished by the animal itself, and it 

 seems sometimes to occur as a natural process. Their 

 tendency toward self-mutilation is so great, in fact, that 

 they cannot easily be handled; they will often separate 

 under the slightest touch. The planarians, a lower 

 group of flat worms, possess the power of regeneration 

 in an even greater degree. When they are divided not 



