Fossil Information Sheet F003
Crinoids
Also known as "Sea Lillies" or "Feather Stars".
They are actually marine animals (not plants) that make up the class Crinoidea of the Echinoderms (phylum Echinodermata).
Most were attached to the sea bed by a flexible stem, circular or pentagonal in section and made up of numerous disc-like plates called columnals.
At the top of the stem was a swollen cup, or calyx, to which the arms were attached.
The Calyx contains the Crinoid's digestive and reproductive organs, and the mouth is located at the top of the dorsal cup, while the anus is located peripheral to it.
The Brachial arms filter food usually plankton from the water.
These creatures were very abundant in the Palaeozic seas of the Cambrian Period.
After death the entire skeleton usually falls apart into small separate plates called ossiccles.
Well preserved Crinoids, therefore, are rare and beautiful fossils.
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