Hydroid (Campanularia flexuosa). Light micrograph (LM) of a colonial hydroid, showing gonozooid (reproducing) and gastrozooid (feeding) polyps, attach


Hydroid (Campanularia flexuosa). Light micrograph (LM) of a colonial hydroid, showing gonozooid (reproducing) and gastrozooid (feeding) polyps, attached to a central stolon (stalk). This hydroid is commonly found growing on seaweed in the inter-tidal zone of the seashore. Hydroid is a collective name for a colony of individuals (polyps). A division of labour exists within the colony: the feeding polyps are cup-shaped and are surrounded by retractable tentacles with stinging cells that catch small prey, and the club-shaped reproductive polyps produce medusae, comparable to little jellyfish. The medusae produce eggs and sperm into the seawater where fertilisation takes place.


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Photo credit: © DR KEITH WHEELER/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: animal, biological, biology, buds, campanularia, cnidarian, coelenterate, colonial, colony, fauna, feeding, flexuosa, gamete-producing, gastrozooid, gonozooid, hydroid, hydrozoa, hydrozoan, invertebrate, invertebrates, light, lm, marine, medusa, medusae, micrograph, microscope, nature, part, parts, polyps, producing, reproducing, reproductive, retractable, sexually-reproductive, spawning, stage, stages, stalk, stolon, structure, tentacles, wildlife, zooids, zoological, zoology