174 



ANARTHROPODA 



bearing nematocysts. The stinging sensation one experi- 

 ences upon picking up a jellyfish is caused by the discharge 



FIG. 203. Development of young jellyfish. The top one is ready to break away 

 After Haeckel. 



of these coiled stinging processes. Each egg deposited by 

 the jellyfish produces a free- 

 swimming young, which soon 

 fixes itself to an object and 

 assumes a form similar to the 

 hydra and grows to the height 

 of half an inch. It then be- 

 comes transversely divided into 

 several parts, giving the animal 

 the appearance of a pile of 

 saucers. The top one soon 

 swims free, and one by one the 



others are also separated and turning upside down lead 

 the free life of the adult forms. 

 The sea anemones may be seen at low tide attached firmly 



