|
 Cnidaria - Sea Anemones
On and surrounding the rocks are an abundance of sea anemones.
The blue-green of the disc and tentacles is due to the presence
in the tissues of one-celled algae. These tiny algae cannot live
in absence of sunlight which is why the green color is not seen
in anemones living in the shade.
Aggregating Anemone - Anthopleura elegantissima
The aggregate anemone are smaller rarely exceeding 2 to 3
inches. It is extremely abundant in upper parts of the middle
tide zone, forming a dense mat completely covering large areas
of the rocks.
Any small object touching the tentacles is instantly penetrated
by scores of toxic stinging barbs. The tentacles are then curved
so as to point toward the mouth while the rhythmic beating of
microscopic cilia move the object along until it drops into the
mouth. Digestion is very rapid, and indigestible portions are
ejected in an amazingly short time.
The stinging barbs of the cnidocytes are too short to penetrate
through human skin and the tentacles may be touched without harm.
 |
Anthopleura xanthogrammica
|
|