Hydra (genus) - Wikipedia
Hydra (/ ˈ h aɪ d r ə / HY-drə) is a genus of small freshwater hydrozoans of the phylum Cnidaria. They are native to the temperate and tropical regions. [ 2 ] [ 3 ] The genus was named by Linnaeus in 1758 after the Hydra , which was the many-headed beast of myth defeated by Heracles , as when the animal has a part severed, it will ...
Hydra | Freshwater, Cnidaria, Polyp | Britannica
2024年10月18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.
水螅屬 - 维基百科，自由的百科全书
水螅 （螅 音同 西， 学名： Hydra），屬於 刺絲胞動物門 中的 水螅綱，多細胞無脊椎動物，包含有芽體（Bud）、 精巢 （Testes）；最常見的有褐水螅（H. fusca），綠水螅（H. viridis）。 水螅和“ 水螅体 ”並無關係，兩者只是名字和長相相似。 管狀且放射對稱的身体延展後可達10毫米，肉眼可看见，上端有口，周围生5～12条小触手，满布刺细胞，用于探寻、捕获猎物、进行防御、辅助移动；身体和触手可以收缩，伸长时可达数倍；基底可以在附着物上滑走，或者以尺蠖状方 …
水螅纲 - 百度百科
水螅纲（Class Hydrozoa），又名水螅水母纲（学名Hydroidomedusa），是 刺胞动物门 水螅虫总纲的一个纲，包括了所有的水母、水螅及珊瑚类动物。 列入《濒危野生动植物种国际贸易公约附录Ⅰ、附录Ⅱ和附录Ⅲ》。 [2] 薮枝螅水母体（期）仅短暂几天到几周浮游于水中，而水螅体则习见于80米以内的浅海，固着在海藻、岩石或其他物体上，靠 出芽生殖，芽体不脱离母体，从而形成5-50㎝大小的树枝状的水螅型群体。 严格说，薮枝螅应名薮枝螅水母，因其 有性生殖 世代为水 …
Hydra Biology Classification, Characteristics and Reproduction
Class: Hydrozoa - Class Hydrozoa is composed of tiny predatory organisms that may live in colonies or as solitary animals. A majority are found in marine environments while a few live in freshwater. Hydrozoa is characterized by an internal digestion space, presence of an exoskeleton, two body forms as well as the presence of cnidocytes
Hydra – Biology, Classification, Characteristics, and Reproduction
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.
Hydroid | Characteristics & Life Cycle | Britannica
Hydroid, any member of the invertebrate class Hydrozoa (phylum Cnidaria). Most hydroids inhabit marine environments, but some hydroids have invaded freshwater habitats. Hydroids may be either solitary or colonial, and there are about 3,700 known species.
Hydrozoa - The World Hydrozoa Database - World Register of …
The Class Hydrozoa is the most diverse group of cnidarians. Although marine species vastly outnumber freshwater ones, the genus Hydra may nevertheless be the best known hydrozoan. It appears in almost all textbooks on invertebrate zoology, but this simple animal is not at all representative of the Hydrozoa as a whole, and may actually give a ...
Hydrozoa - Wikipedia
Hydrozoa (hydrozoans; from Ancient Greek ὕδωρ (húdōr) 'water' and ζῷον (zôion) 'animal') is a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water.
Cnidaria - Hydrozoa - MESA
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), …