Eocrinoidea
| Eocrinoidea Fossil range: Cambrian–Silurian |
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 Eocrinoid holdfasts (Middle Ordovician, Utah)
 Colourful reconstruction of Gogia ojenai
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The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian.
The eocrinoids were a paraphyletic group that may have been ancestral to six other classes: Rhombifera, Diploporita, Coronoidea, Blastoidea, Parablastoidea, and Paracrinoidea. The earliest genera had a short holdfast and irregularly structured plates. Later forms had a fully developed stalk with regular rows of plates. They were benthic suspension feeders, with five ambulacra on the upper surface, surrounding the mouth and extending into a number of narrow arms. An unusual Ordovician form was the conical Bolboporites with its single brachiole. See also List of echinodermata orders.
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