oral arm

oral arm

[′ȯr·əl ¦ärm]
(invertebrate zoology)
In a jellyfish, any of the prolongations of the distal end of the manubrium.
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These includes: larval length (LL), larval width (LW), body length (BL), post oral arm length (POA) and anterolateral arm length (ALA) (Figure3).
Among the salinity treatments, 4-arm pluteus larvae at 28 ppt had the lowest larval, body and post oral arm length of 197.
Medusae collected in the southeastern United States were each biopsied for a tissue sample of tentacle, oral arm, or both, that had been preserved in 75%-100% ethanol before the rest of the medusa was preserved in 10% buffered formalin in seawater.
421 bd Gonad color light brown or light light brown or light pink pink (2) Oral arm number 4 4 (4) Manubrium width at no data 0.
1): (1) bell margin tissue--a concentric ring about 1 cm in width, running around the perimeter of the bell; (2) oral arm tissue--the outpocketings of the gastrovascular cavity and overlying tissue layers that extend up into the water column; (3) the epithelial layer from the oral (subumbrellar) and aboral (exumbrellar) regions of the bell; (4) isolated mesogleal tissue; and (5) samples of intact bell tissue along a radial transect extending from the bell margin to the manubrium (the gastrovascular cavity located at the center of the bell).
Samples of intact oral arm tissue from field-condition and bleached animals were also excised from the animal and analyzed for CA activity and algal density.
In addition to the measurements described above, about 200 medusae from each population were cursorily examined for the following characters, then released: manubrium shape, number of marginal scallops, oral arm length, number of radial canals emanating from each gastro-genital sinus, bell shape and color, and if female, the location and pattern of larval brood.
Images obtained by this method show excellent detail of the oral arm surface and good contrast at the boundaries between external plates [ILLUSTRATION FOR FIGURE 5 OMITTED].
When making contact with a jellyfish, phyilosomas first cling onto its exumbrella, feed on its tentacles or oral arms, and then consume the exumbrella.
Capture locations were visible for all major surfaces (lappets, subumbrella, oral arms, and tentacles) during the course of medusan development.
Long, delicate tentacles and relatively thick oral arms extended perhaps 6 m below the bell in life.