Small, like Little Black Mussels. Some closed ones and some open in this photo.
Not sure what the blue bit is, giving birth to a new anemone?
Dozens of gorgeous Metridium senile or Short Plumose Anemones were growing on this metal pipe off a dock in the marina. The largest were about 3" long and the smallest just a fraction of an inch.
In tidal pool at Kaikoura. Most bizarre thing I've seen for a long time.
soft coral, Cespitularia, spawning at Malajibomanoc Island, Philippines
These two seem to have fused together.
Cnidaria (/naɪˈdɛəriə/ with a silent c) is a phylum containing over 10,000species of animals found exclusively in aquatic and mostly marine environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. They have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths...