Cnidaria
Related Category: Zoology: Invertebrates
(ndâr´) or Coelenterata(slnträ´t), phylum of invertebrate animals comprising the sea anemones, corals, jellyfish, and hydroids.
Cnidarians (Phylum Cnidaria) are a group of aquatic animals that includes jellyfish, corals, sea anemones, and hydras.
Cnidarians live in aquatic environments and inhabit all depths, from the sandy substrate up to the surface.
Cnidarians
Physical Charecteristics
Cnidaria are some of the simplest and most beautiful "animals." These creatures are flower-like and resemble plants in many respects.
Cnidarians have a true mouth and digestive cavity, but no anus. What goes in, also must come out the same opening! Tentacles surround the mouth opening to trap prey. These animals are usually carnivores, eating crustaceans, molluscs and small fish.
Cnidarians have two basic body forms, medusa and polyp. Medusae, such as adult jellyfish, are free-swimming or floating. They usually have umbrella-shaped bodies and tetramerous (four-part) symmetry.
Cnidaria Scyphozoa Aurelia
Type:
The animal group that the species belongs to...
Cnidarians (~1,376 species)
Comb jellies (Sea Gooseberry, etc.) - 5 species
Sea nettles and other jellyfish - 10 species (thimble jellyfish, Linuche unguiculata)
Siphonophores - 5 species
Sea anenomes - 10 species ...
Cnidarians, annelids, mollusks, crustaceans, and plankton
INCUBATION:
Eggs develop relatively rapidly, exhibiting an incubation period of approximately 24 hours ...
Jellyfish: Cnidaria
Appearance:
Jellyfish are neither jelly nor fish. Jellyfish lack backbones, heart, blood, brain, or gills and, in fact, are over 95% water. Jellyfish possess stinging cells located on the tentacles and other body parts.
Unlike other cnidarians, anemones (and other anthozoans) entirely lack the free-swimming medusa stage of the life cycle: the polyp produces eggs and sperm, and the fertilized egg develops into a planula that develops directly into another polyp.
The "hydroid" cnidarians typically which grow up into large, elegantly branched forms. All the zooids of a colony are asexually produced from one parent zooid.
Examples of "hydroids" are: ...
In the development of the Hydrozoa, and indeed of the Cnidaria generally, the egg usually gives rise to an oval larva which swims about by means of a coating of cilia on the surface of the body.
Jellyfish (also known as jellies or sea jellies or Medusozoa) are free-swimming members of the phylum Cnidaria.
cnidocyst -- The "stinging cell" of a cnidarian.
coelom -- Fluid-filled cavity within the body of an animal; usually refers to a cavity lined with specialized tissue peritoneum in which the gut is suspended.
Invertebrates: animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
Despite the simplicity of the digestive chamber, they are significantly more complex than cnidarians in that they possess numerous organs, and are therefore said to show an organ level or organization.
The major invertebrate phyla are porifera (sponges), platyhelminthes (flatworms), nematoda (round worms), annelida (earthworms, marine worms and leeches), cnidaria (jellyfish, coral and sea anemones), mollusca (octopus, nautilus, squid, slugs, ...
Revision of Microplasma parallelum Etheridge, 1899 (Cnidaria: Rugosa) from the Middle Devonian Moore Creek Limestone of New South Wales ...
 See also: Crustacean, Snail, Reptile, Purple, Mollusk
|
