A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are roughly cylindrical in shape and elongated at the axis of the vase-shaped body. In solitary

Hydra is a genus of small freshwater hydrozoans in the phylum Cnidaria. They are solitary, carnivorous jellyfish-like animals, native to the temperate and tropical regions. The genus was named by Linn