HYDRAS. 165 



CHAPTER VI. 



Hydras. 



When Hercules was going about doing those wonder- 

 ful things of which we have all heard, it was suggested 

 that he should turn his attention in the direction of 

 Lake Lerna, near Argos, where a monster with a hun- 

 dred heads was making itself unpleasantly active. He 

 visited the place and interviewed the creature, but 

 when he had cut off one of the heads, he must have 

 been surprised to see two new ones sprout out of the 

 bleeding surface. It was discouraging, but the hero 

 began to have the best of the contest when he began 

 to burn the fresh cuts with a hot iron. The monster 

 was the Hydra of mythology. Science has preserved 

 its memory by giving the name to a common and pe- 

 culiar creature inhabiting all our ponds and ditches. 

 The fresh-water Hydra (there are no salt-water Hydras) 

 has a soft and elastic body, elongate cylindrical in 

 form, attached by the tip of one end to an aquatic 

 plant or other submerged object, arid from eight to 

 ten long fine arms arranged around a mouth at the op- 

 posite end. 



There are two species, the green {H. viridis) and 

 the brown {H. vulgaris), both being very common. 

 The whole animal is elastic, and when extended may 



