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a blind, saclike cavity lined by gastrodermis and opening to the exterior via the mouth which functions in extracellular digestion, circulation, excretion, reproduction, and hydrostatic skeletal support
a body plan where a vertical section along an axis or through any radius produces mirror-image halves
an elevated region, with the mouth at its summit, situated in the center of a cnidarian's oral disc
the region of a cnidarian's body with the mouth and manubrium at its center, and a whorl of tentacles at its margin
a chitinous exoskeleton secreted by the pedal disc and column of a polyp that provides protection and attachment to the substratum
a tubular body wall outgrowth that includes the coelenteron, from which zooids bud at intervals along its length
a cnidarian growth form that consists of a single or branched tubular body wall outgrowth attached to the surface of the substratum, that grows in a two-dimensional network and bears upright, unbranched zooids
a continuous mat-like sheet of stolonate tissue that unites the zooids and attaches the colony to the substratum
a network of hollow gastrodermal tubes, located between the upper and lower epidermal surfaces of the coenosarc, that course through the mesoglea and interconnect the zooidal coelenterons
an upright, plantlike cnidarian growth form that may be grassy, bushy, shrubby, or feathery in appearance
the principal halo-shaped, circular muscle of medusae located on the subumbrellar surface
a complex two-dimensional system of interconnected neurons located in the epidermis and gastrodermis, joined together by neurons in the mesoglea
the radiation of nerve impulses through a nerve net like ripples from a pebble tossed in a pond
a brainlike concentration of neurons that receives sensory input, integrates the information with other inputs, and generates motor output
a combined sensory-effector cell that plays a central role in prey capture and defense; a unique and defining feature of cnidarians
a fluid-filled membranous capsule containing a long tubular invagination of the capsule wall that, upon stimulation, everts explosively to the exterior to sting prey or to adhere to the surface of an animal or substrate
a type of cnida found in all cnidarians that has spines or barbs on the surface of the discharged tubule
a thin-walled cnida occurring only in anthozoans that contains a coiled, spring-like tubule that, when discharged, releases tiny, sticky threads
enzymatic gland cells
the secretory cells lining the gastrodermis which release proteases that digest prey extracellularly
the ciliated, free-swimming planktonic larva of cnidarians that settles to the bottom and metamorphoses into a juvenile
the vertical partitions of gastrodermis and mesoglea that divide the anthozoan coelenteron into radial compartments
the long, threadlike, cnidae-bearing extensions of the septa which spew from the mouth and tentacle tips when the body suddenly deflates; used for defense, prey capture, and extracorporeal digestion of prey
the strongly-developed and conspicuous longitudinal septal muscles of anemones which, upon contraction, invaginate the oral disc and tentacles and shorten the body column
a specialized form of fragmentation in anemones where small pieces of the pedal disc detach and develop into small anemones
the skeletal cup around the polyp of a stony coral, which the polyp can retract into for protection
the process where zooxanthellae corals expel some or all of their algae due to adverse conditions such as under- or overillumination, excess UV exposure, salinity fluctuation, and low or high temperatures
the taxon that includes cnidarians with a medusa stage in their life cycle, such as Scyphozoa and Hydrozoa
a hollow invagination of the oral disc extending deeply into the septa of large jellies
the slender, threadlike clusters found at the septal margins of large jellies that bear nematocytes and enzymatic gland cells used in subduing prey and digestion
the rounded, scalloped lobes on the umbrellar margin of large jellies which provide flexion points during bell contraction
the knoblike sensory organs of large jellies consisting of a statocyst, a mechanoreceptor, and a chemoreceptor (and sometimes a photoreceptor); provide information related to gravity-equilibrium, waterborne vibrations (hearing), as well as odor and light detection
an iris diaphragm located below the bell of a hydrozoan medusa that creates a powerful water jet as the jelly swims
the incompletely differentiated medusae of colonial hydrozoans that produce gonads, but lack some or most other medusan traits
the protective or food-catching polyps of colonial hydrozoans that contain batteries of nematocytes
a class of cnidarians including the sea anemones, corals, sea fans, sea pens, and sea pansies
a class of cnidarians including the large jellyfish, as well as box jellies, stalked jellies, flag-mouth jellies, and root-mouth jellies
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