SEA ANEMONES, CORALS, HYDROIDS, HYDROCORALS, JELLIES AND OTHERS—Phylum CNIDARIA (aka Coelenterata)

Includes anemones, zoanthids, corals, gorgonians, sea pens, sea whips, hydroids, sea firs, hydrocorals and a variety of forms casually called “jellyfish” or “jellies.”
Central to each cnidarian is a digestive system with one opening—yes, the mouth is also the anus! Ringing the opening is a circle of tentacles that have a definitive radial symmetry. The tentacles are festooned with millions of cells called cnidocytes, each of which has a tiny, harpoon-like mechanism. Prey capture is a common function of these specialized cells, many of which contain an associated toxin.
A cnidarian has one of two body types: the polyp or the medusa. The polyp, an example of which is shown in photograph A—rose anemone (CN8)—features a ring of tentacles and mouth/anus configuration atop a columnar body and exists either as a solitary entity or as part of a group with countless others.
In the case of sea anemones, these groups of polyps are clones, and members can be referred to as clone-mates. In the medusa body type, an example of which is shown in photograph B—sea nettle (CN91), a ring of tentacles and mouth/anus layout hang beneath a bell-shaped or pancake-shaped sac. This body form is usually free floating. Some cnidarian “rascals” have life cycles that alternate these two forms. More than 500 cnidarian species live in the Pacific Northwest.