Hydra is a genus of simple fresh-water animal possessing radial symmetry. Hydras are predatory animals belonging to the phylum Cnidaria and the class Hydrozoa. They can be found in most unpolluted fresh-water ponds, lakes and streams in the temperate and tropical regions and can be found by gently sweeping a collecting net through weedy areas. They are usually a few millimetres long and are best studied with a microscope. Biologists are especially interested in hydras due to their regenerative ability; and that they appear not to age or die of old age. However, there is not scientific unanimity yet on whether Hydra undergo senescence, as discussed below.
Sunday, October 24, 2010
In Greek mythology, the Lernaean Hydra was an ancient nameless serpent-like chthonic water beast (as its name evinces) that possessed nine heads — and for each head cut off it grew two more — and poisonous breath so virulent even her tracks were deadly. The Hydra of Lerna was killed by Heracles as one of hisTwelve Labours. Its lair was the lake of Lerna in the Argolid, though archaeology has borne out the myth that the sacred site was older even than the Mycenaean city of Argos since Lerna was the site of the myth of the Danaids. Beneath the waters was an entrance to the Underworld, and the Hydra was its guardian.
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