84 POND LIFE 



seems that a colony once started continues until not a single 

 individual is left. Mucedo when carefully examined bears a 

 similarity to a mass of greenish jelly. On the appearance of 

 the Polipedes, it is now no longer so uninteresting an object, 

 but somewhat resembles a woolly caterpillar, a creature so 

 original and beautiful that, if once seen, it will not readily be 

 forgotten, for the effect of these minute graceful plumes, 

 waving in all directions, is certainly most astonishing. 



CHAPTER VIII 



HYDRA 



THIS little animal, containing chlorophyll, a substance usually 

 only found in plants, has the honour to have an order practi- 

 cally produced for its particular benefit. It is a member of 

 the " Eleutheroblastea," a tongue-twisting name with an 

 ending that is a nasty word to some minds. 



The Hydra is one of the few Coelenterates to occur in fresh 

 water, but it is by no means exclusively British, nor even 

 European, occurring as it does in so many parts of the 

 world. 



At certain seasons, particularly towards the end of summer, 

 hydras increase enormously ; on every stick, plant, stone, &c., 

 hundreds of these beautiful little creatures will be discovered, 

 some fat and short, others thin and long, some with " little 

 hydras " projecting from their sides (buds), others with swell- 

 ings which on examination prove to be egg-bags, but in one 

 respect they are all alike each one ends in a number of 

 tentacles. Perhaps while we are watching we may have the 

 fortune to see a small "cyclops" brush against a tentacle, 

 and then it will be noticed that the accident, which hardly 

 seemed severe, was certainly so, for the cyclops is gradually 

 drawn towards the hydra's mouth. One wonders why the 

 victim does not at least make an attempt to escape. A 

 microscope would have revealed that when the unfortunate 

 crustacean touched the hydra numbers of long threads were 

 instantly shot out, and these threads in some way or other 

 paralysed the victim. 



The mouth, which would better be named the stomach for 

 in the case of the hydra it is one and the same thing, and 

 resembles the latter more than the former can expand to 



