Slatkovodni polip iz kola dupljara, vrlo proste građe i sa 6-8 pipaka oko usnot otvora; fig. zlo koje biva time veće pto se više trudimo da ga otklonimo.
ETYM Latin hydra, Greek jydra; akin to hydro water. Related to Otter the animal, Water.
Small tubular solitary freshwater hydrozoan polyp.
In zoology, any member of the family Hydridae, or freshwater polyps, of the phylum Cnidaria (coelenterates). The body is a double-layered tube (with six to ten hollow tentacles around the mouth), 1.25 cm/0.5 in long when extended, but capable of contracting to a small knob. Usually fixed to waterweed, hydras feed on minute animals that are caught and paralyzed by stinging cells on the tentacles.
Hydras reproduce asexually in the summer and sexually in the winter. They have no specialized organs except those of reproduction.