What Do You Know About Hydra And Medusa?

Hydra and Medusa (Jelly fish) both belong to the phylum named as phylum coelenterate. Hydra is a fresh water animal and it is found attached to rocks or other aquatic plants but they also have some abilities to move. It is six to ten millimeter long in a squeezed condition but can elongate its body from 20 to 30 cm. Its mouth is surrounded by many tentacles. Tentacles are provided with many stinging cells which act as organs of defence and offence. Tentacles capture prey by paralysing it with stinging cells and push food into the mouth while undigested food is also digested through the mouth.  

Jelly fish is exclusively marine and found near the surface of water. It ranges in size from two to forty centimeter while some jelly fish are larger in size. Their tentacles may reaches to fifteen meters in length and it has a cup shaped body. It has a convex upper side due to which it is called a cup animal. Body is transparent and is thus not easily visible in water. Its shape is like an open umbrella. The mouth is present on the lower side of the body at the end of the triangular structure expanded on four arms with tentacles at their margin.