Cystoids for Sale
Cystoids for Sale – We have a nice selection of Fossil Cystoids for Sale.
Cystoids were any member of an extinct class (Cystoidea) of primitive echinoderms (animals with a hard, calcareous external skeleton, related to the modern sea lily and starfish).
They first appeared during the Middle Ordovician Epoch and persisted into the Late Devonian Epoch (the Ordovician Period began about 488 million years ago, and the Devonian Period ended 359 million years ago).
Once diverse and important, the cystoids had sac-like bodies that were attached to a stem anchored to the sea floor. Numerous plates covered the body.