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(invertebrate zoology)
A larval, free-swimming medusoid stage of scyphozoans; arises from the scyphistoma by transverse fission. Also known as ephyrula.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



the larva of most coelenterates of the class Scyphozoa. The larvae are formed asexually by means of transverse fission of the polyploid generation—the scyphistoma. The edge of the umbrella forms eight double lobes. Tentacles and oral lobes are absent. The digestive system is rudimentary: in addition to the stomach, there are only two rudiments of radial canals. The youngest ephyrae are transparent and reach several mm in diameter. Transformation into an adult jellyfish is accompanied by rapid growth. The edge of the umbrella becomes more regular, and a complex gastrovascular system, lateral tentacles, and the rudiments of sex glands develop.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Instead, within the first two days after the injury, the ephyra had reorganized its existing arms to be symmetrical and evenly spaced around the animal's disklike body.
In the few cases when the injured animals do not symmetrize--only about 15% of the injured animals they studied--the unsymmetrical ephyra also cannot develop into normal adult jellyfish, called medusa.
(5) Young jellyfish, called ephyras, eat and grow into adults.
The localization of FMRFamide and tubulin immunoreactivity was best followed through a developmental sequence starting with the just-budded ephyra of Aurelia since the two stained subumbrellar networks showed very different relationships with the locomotory musculature in the early medusoid forms.
A tubulin-IR network was associated with the swim musculature of ephyra, staying within the limits of the circular muscle disc and the two radial muscle bands that run on either side of each ephyral arm.
Growth of ephyra included a disappearance of the arms and an extension of the circular muscle disc toward the manubrium.
Miscellaneous organisms consisted of Platyhelminthes, brachiopods, two cyclopoid copepods, nematodes, and a single ephyra of Aurelia spp.
To examine the kinematic profile of a swimming ephyra and its lappets, we used video (250 fps) of a 0.32-cm ephyra swimming in 64-[micro]m-filtered seawater.
High-speed (250 fps) video recordings of fluorescein dye transport around a swimming ephyra demonstrated boundary layer occlusion of the inter-lappet clefts.
Table 1 Morphological characteristics of Cyanea capillata developmental stages Age Diameter Stage (days) (cm) Morphological traits Ephyra 1-3 0.2-0.44 Bell deeply cleft between lappets Manubrium small and simple Tentacles generally absent, some with one tentacle Early 3-7 0.45-0.64 Clefts between lappets pronounced tentaculate Manubrium simple Two tentacles present, rudiments of others evident Mid- 7-14 0.65-1.0 Clefts between lappets reduced due to tentaculate growth of central bell disk and lappet widening Manubrium growth and elaboration into oral arms.
Measurements were repeated at 48 h, and growth was recorded as the mean daily increase in ephyra diameter.
Ephyra size was positively related to food; diameters increased by 10.6% [+ or -] 13.8% [d.sup.-1] in those fed 5 rotifers [d.sup.-1] and by 29.2% [+ or -] 25.4% [d.sup.-1] in those fed 10 rotifers [d.sup.-1].