Hydra (/ ˈ h aɪ d r ə / HY-drə) is a genus of small freshwater hydrozoans of the phylum Cnidaria. They are solitary, carnivorous jellyfishlike animals [ 2 ] , native to the temperate and tropical regions.

2025年2月1日 · Hydra, genus of invertebrate freshwater animals of the class Hydrozoa (phylum Cnidaria). The body of such an organism consists of a thin, usually translucent tube that measures up to about 30 millimetres (1.2 inches) long but is capable of great contraction.

Hydra is a genus of tiny fresh-water organisms that are classified under the phylum of Cnidaria. Hydra has a cylindrical, radially symmetric body from 2 to 20 mm in length. It is visible to the naked eyes when fully extended. Typically, hydras remain attached to some underwater objects, waving their tentacles slowly with the current.

Hydra are a genus of small, fresh-water organisms that are classified under the phylum Cnidaria. In addition to being related to such organisms as jellyfish, they are characterized by their tiny, tube-shaped bodies that contain several tentacles on one end.

Hydra vulgaris, the fresh-water polyp, [3] is a small freshwater hydroid with length from 10 mm to 30 mm and width about 1 mm. [4] The hydra have four to twelve tentacles that protrude from just outside the mouth. They feed by extending their tentacles …

Hydra are inconspicuous freshwater relatives of corals, sea anemones and jellyfish. All are members of the phylum Cnidaria, characterized by radially symmetrical bodies, presence of stinging tentacles and a simple gut with only one opening (gastrovascular cavity).

2023年8月3日 · Hydra are inconspicuous freshwater relatives of corals, sea anemones, and jellyfish that are classified under the phylum Cnidaria, Class Hydrozoa, Order Anthomedusae/Anthoathecata, and Family Hydroidea. It is essentially a sedentary organism living attached to stones, pebbles, and water plants, but can get …

2010年11月23日 · What is Hydra? Hydra is a member of the animal phylum Cnidaria. This phylum includes corals, sea anemones and jellyfish. While most cnidarians are marine, Hydra is unusual in that it lives exclusively in fresh water. Hydra was first described by Antoni van Leeuwenhoek (1632–1723) in a letter he sent to the Royal Society on Christmas day, 1702.

2025年1月31日 · The four distinct groups: oligactis (stalked hydra), vulgaris (common hydra), viridissima (symbiotic green hydra), and braueri (gracile hydra); were identified primarily based on certain morphological features like sexual characteristics and the shape and size of their cnidocysts (Campbell, 1987).

Hydra, found in slow-moving waters, are the best known and most researched freshwater hydrozoan. Hydra has a base plate that helps it attach to substrates, and like all cnidarians uses nematocysts to catch its prey. They eat small crustaceans (e.g.brine shrimp), …