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Northwest Wildlife Online
Phylum Cnidaria
Hydras, Jellyfish, Sea Anemones, and Corals
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Protozoans Sponges Cnidarians Ctenophores Arthropods Echinoderms Mollusks Nematodes Flatworms Annelid Worms
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On the left is the Giant Green Anemone (Anthopleura xanthogrammica). Over 6 inches long this anemone gets its beautiful emerald color thanks to a symbiotic relationship with green algae. On the right is the Frilled or Plumose Anemone (Metridium senile). Two feet or more in length, these are the giants of the anemone world.
Three Classes of Phylum Cnidaria represent wildlife in the Northwest:
Class Hydrozoa - Hydras
Class Scyphozoa - Jellyfish
Class Anthozoa - Anemones and Corals
Simply designed and often brilliantly colored, the Cnidarians are an ancient, primitive, and widespread group of animals. Many species are easily observed from our shores and give tide pools an exotic, magical appearance. But many are capable of nasty stings thanks to thousands of tiny biological missiles called nematocysts hidden in their tentacle. With the exception of some hydras the cnidarians phylum is primarily confined to salt water.
A Sea Blubber, Cyanea captilla, in a posture often seen - stuck against a boat dock. Sea Blubbers are large jellies reaching 20 inches or more across with tentacles out to 30 feet. The Plumose Anemones will eventually eat this one. On the right is a picture of a beached WaterJelly, Aurelia spp., showing the beautiful symmetry of this cnidarian. This particular specimen was photographed by my daughter, Maria. The typically grow to five inches across and are luminescent in the dark.
Cnidarians all share the same basic body structure. They display radial symmetry and have tentacle for catching prey. Their prey ranges from the large fish caught by jellyfish to the tiny free floating organisms snatched up by coral. Unlike the filter feeding sponges, cnidarians have a definite mouth and a digestive cavity.
Cnidarians live in two different forms: the stationary, sessile, type known as a polyp; and the free swimming form, called a medusa. The sessile body type is well known to anyone who has seen anemones clinging to the shore or boat dock. Jellyfish display the medusa form.
Protozoans Sponges Cnidarians Ctenophores Arthropods Echinoderms Mollusks Nematodes Flatworms Annelid Worms
Birds Mammals Reptiles Amphibians Fish Invertebrates Library NWWOL Online Store Home
Mission Editor Bio Site Map Contact Wildlife Park Links Further Study Wild Employment Northwest Trek
