Explore: Fossil Hydrozoa

Hydrozoa (hydrozoans; from Ancient Greek ὕδωρ (húdōr; "water") and ζώα (zóa; "animals")) is a taxonomic class of individually very small, predatory animals

sea pens); swimming Scyphozoa (jellyfish); Cubozoa (box jellies); and Hydrozoa (a diverse group that includes all the freshwater cnidarians as well as

the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not. Since jellyfish have no hard parts, fossils are

change colour; some are covered with other organisms, such as algae or hydrozoa. In keeping with this camouflage, frogfishes typically move slowly, lying

Reports. 27: 1–162. Brinckmann-Voss, A. (1970). "Anthomedusae/Athecatae (Hydrozoa, Cnidaria) of the Mediterranean. Part I. Capitata". Fauna e Flora del Golfo

produced asexually, as by budding or fission. Siphonophorae for colonial Hydrozoa which superficially resemble the other Cnidaria colloquially referred to

Accessed through: Schuchert, P. (2014) World Hydrozoa database at http://www.marinespecies.org/hydrozoa/aphia.php?p=taxdetails&id=13551 on 2014-10-31

worms, clams, mussels, predatory crustaceans, barnacles and small fish. Hydrozoa, also known as hydroids, inhabit SMEs and feed on surrounding algae and

association with any of these classes has been established. An affinity with the hydrozoa (as a flotation device) has been considered, although some authors oppose

sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species