The swim system includes a cluster of pacemaker cells in each rhopalium; a conducting system in the nerve ring, which links the rhopalial pacemakers but also distributes excitatory impulses to the subumbrella; and a subumbrellar
motor nerve net, which synaptically activates the circular muscle that lines the bell cavity (Satterlie, 1979; Eichinger and Satterlie, 2014).
swim musculature of scyphozoan jellyfish presents an interesting problem for neuronal control due to several unique features.
Immunohistochemical staining of scyphomedusae with monoclonal antibodies against [alpha]- or [beta]-tubulin shows a subumbrellar
nerve net that has the distribution and neuronal characteristics of the motor nerve net that controls the swim musculature (Giant Fiber Nerve Net, also called the Motor Nerve Net; Horridge, 1956a, b; Schwab and Anderson, 1980; Anderson and Schwab, 1981).
5 (defined as bell length/bell width)) and constricted orifices leading to the subumbrellar
cavity (Daniel, 1983, 1985; Colin and Costello, 2002; Dabin i et al.
high aspect or fineness ratio) with constricted orifices leading to their subumbrellar
cavities (Colin and Costello, 2002; Dabiri et al.
Family Cyaneidae is distinguished from other semaeostome families on the basis of three characters: in cyaneids, tentacles arise from the subumbrella away from the bell margin, pendulous gonads hang below the subumbrella in complexly folded eversions of the subumbrellar
wall, and the stomach forms radiate pouches that terminate in rudimentary (i.
1) and presents a restricted surface area in comparison to the lappets or subumbrellar
For each individual, replicate nematocyst densities were determined by examining two locations for each of the main prey capture surfaces (lappets, subumbrellar
surface, manubrium, and tentacles).
The rhopalium is connected to the subumbrellar
tissue by a rhopalial stalk that runs through to the subumbrella.
Pieces of tissue from tentacles, subumbrellar
vesicles, and gastric filaments were smeared on a slide; nematocysts in these smears were examined using differential interference contrast microscopy at 100X magnification.
Higher densities of zooxanthellae have been observed associated with the subumbrellar
(oral) epithelial tissue of the bell than with the exumbrellar (aboral) bell tissue (Blanquet and Riordan, 1981; Blanquet and Phelan, 1987).
Oral arms 4, perradial, straight or curved at 90[degrees] angles typically counterclockwise (but occasionally variable), arising from base of manubrium; length short, reaching approximately to bell margin (thus only [+ or -] 1/3 bell diameter); extending laterally outward against subumbrellar
surface of bell.