subumbrella


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Related to subumbrella: radial canal

subumbrella

[¦səb·əm′brel·ə]
(invertebrate zoology)
The concave undersurface of the body of a jellyfish.
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We found a high incidence of flowers attacked by the larvae of Olycella subumbrella Dyar, which reduced individual fruit set from 20% to 100% (Fig.
Predation of flowers by the larva Olycella subumbrella reduced individual fruit set by 20% to 100%, a role that has been largely ignored in the past but seems to be getting more attention recently (McCall, 2008; Pina et al., 2007).
For subumbrellar recordings, the electrodes were attached directly to the nerve ring, on the subumbrella or velarium about 1 mm from the nerve ring (= near the nerve ring), or in the center of a muscle sheet quadrant.
Connections were tested between single-tentacle responses and swimming activity with dual recordings in which one electrode was placed on a tentacle and the other on the subumbrella immediately adjacent to (above) the nerve ring.
Tissue pieces were dissected from small and large adult Aurelia, including pieces from the margin (including tentacles), from the more peripheral subumbrella and more central subumbrella, the exumbrella, and the manubrium.
It passed through the region of circular muscle with a more radial orientation (perpendicular to that of the tubulin-IR network), and continued across the subumbrella, extending into the manubrium, maintaining a radial primary orientation (Fig.
The motor nerve net of the perradial frenula is also notable in that neuronal density appears greater than that of the velarium or subumbrella (based on qualitative assessments; Satterlie et al., 2005).
Here we provide a quantitative confirmation of network density differences in the subumbrella, velarium, and frenula within and between cubomedusan species, as part of a thorough examination of their ectodermal nervous system.
For instance, fine hairlike tentacles arise from concentric horseshoe-shaped rows at the base of the adradial marginal lappets in species of Cyanea, whereas thick ribbonlike tentacles arise in a straight line at the base of the adradial marginal lappets in Desmonema; in contrast, tentacles arise from a broad annular band toward the center of the subumbrella in Drymonema (e.g., see Fig.
Semaeostome with eight rhopalia in deep niches of the subumbrella away from the bell margin; tentacles within an annular zone of the subumbrella delimited proximally by the manubrium and distally by the radius to the rhopalia; gastrovascular cavity consists of radial pockets, separated by gastric mesenteries, which bifurcate numerous times toward the bell margin; ring canal absent.
This suggests that asymmetric contractions of the subumbrella and velarium (including frenula) must involve regionally enhanced contractions of the swim musculature.
In our investigation of the neural and muscular organization of the swim system of the cubomedusa Tripedalia cystophora Conant, 1897, our attention was drawn to the four velarial frenula--buttress-like muscular brackets that brace the right-angle connection between the velarium and subumbrella in the perradii.