Hydrozoa

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Related to hydrozoans: anthozoans, scyphozoans

Hy·dro·zo·a

(hī-drō-zō'ă),
A class of coelenterates or jellyfish, including Hydra, a freshwater polyp, Physalia, the "Portuguese man-of-war," Millepora, a stinging coral, and the sea wasps, Chironex heckeri and Chiropsalmus quadrigatus, the stings of which can cause severe wheals, pain, skin necrosis, and occasionally, rapid death from respiratory and cardiac depression.
[hydro- + G. zōon, animal]
References in periodicals archive ?
Pattern in intertidal hydrozoan distribution along the coast of Sao Paulo State, Southeastern Brazil.
Muscle cells with reduced epithelial components, or "pure myocytes" (without an epithelial component), are best seen in the swim musculature of scyphozoan, cubozoan, and some hydrozoan meduase (Chapman, 1974; Satterlie and Spencer, 1983: Satterlie, 2011, 2015).
The filaments of Trichodesmium are visible to the naked eye, and support other organisms, such as hydrozoans and even fungi, which potentially make them a kind of pelagic lichen.
Their goal is not to catch fish but to haul in hard data documenting trawling's impact on tube worms, sponges, anemones, hydrozoans, urchins, and other denizens of the deep.
These sponges typically inhabit a depth from 2 to 20 meters and usually are epibionts of red algae Odonthalia dentata and Ptilota gunneri, as well as various hydrozoans and bryozoans.
Around 100 species (polyps and medusae) are reported from the state of Parana, of which 89 are hydrozoans (including hydromedusae, solitary and colonial hydroids), nine are scyphozoans (typical jellyfish) and two are cubozoans (box jellyfish) (Marques et al., 2003; Oliveira et al., in press).
Limpet stomachs contained 78 taxa, including filamentous cyanobacteria, diatoms, brown and red algae, marine seagrass, foraminifera, hydrozoans, bryozoans, nematodes, bivalves, gastropods, crustaceans, and tunicates.
Several groups of cnidarians (hydrozoans, alcyonarians, antipatharian (black) corals, corallimorpharians, zooantharians, madreporarians), and bryozoans fit into this category.
The fastest strike observed took 0.33 millisecond (ms), beating out other record movements such as the release of stingers by hydrozoans (jellyfish) at 0.5 ms or the escape jump of click beetles at 0.6 ms.
We believe that [PpCa.sub.v][beta] forms part of VGCC complexes that underlie synaptic transmission of sensory information and efferent events detected by cnidocytes to postsynaptic cells such as neurites and other cnidocytes, in a manner similar to that observed in other hydrozoans (Thurm et al., 1998b, 2004; Holtmann and Thurm, 2001; Oliver et al., 2008; Scappaticci et al., 2010).
Sessile epibiont organisms such as hydrozoans, sponges and particularly epiphytic algae influence the abundance and diversity of phytal fauna (Kangas, 1978; Leite & Turra, 2003), because they increase the complexity of the macrophytes on which they develop (Bell et al, 1984; Hall & Bell, 1988).