A comparison of the muscular organization of the rhopalial stalk in Cubomedusae (Cnidaria)

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Barbara Smith (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/

Abstract: In the phylum Cnidaria, little is known about the organization of sensory systems of the motile forms, jellyfish. Cubomedusae, or box jellyfish, have four sophisticated sensory structures (rhopalia), one on each side of the box-shaped bell. Each rhopalium contains a statolith, two complex eyes, four ocelli and sensory epithelia, and is suspended by a stalk within a cavity (niche) that opens on the outside of the bell. The function of the stalk, beyond forming a connection between the rhopalium and the bell, is largely unknown. Electron microscopy and light microscopy were utilized to determine the function of the rhopalial stalk and compare stalk morphology among four species of box jellyfish (Cnidaria: Cubozoa), with an emphasis on muscle fiber organization. A branch of the gastrovascular cavity forms the center of the stalk surrounded by the gastrodermis, mesoglea and epithelium. Epitheliomuscular cells make up the majority of the epithelium. Muscle fibers are smooth, longitudinal and asymmetrically arranged around the periphery of the stalk. In three out of four species, the stalk bends or shortens in response to potentially injurious stimuli to move the rhopalium into a more protective position. The structure of the rhopalial niche varies in each species and can be correlated to muscle fiber percent area.

Additional Information

A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Cubomedusae--Morphology, Cubomedusae--Physiology , Jellyfishes--Anatomy , Jellyfishes--Research, Marine invertebrates--Research
Cubomedusae -- Morphology
Cubomedusae -- Physiology
Jellyfishes -- Anatomy
Jellyfishes -- Research
Marine invertebrates -- Research

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