THE FRESH-WATER HYDRA. 



85 



other ways in which the baby-hydr^: are born, but you 

 can study more about them when you become scientific 

 men and women. If you find out all about the hydra, 

 you will have done a harder and more useful work than 

 that which Hercules did, when he killed the hydra with 

 fifty heads that lived in Lake Lerna. 



