page_title: List of prehistoric echinoderm genera
section_title: X
hierarchical_section_title: List of prehistoric echinoderm genera / X
caption_attribution_description: English: Xenocrinus baeri (Meek, 1872); Upper Ordovician crinoid calyx from the Bull Fork Formation, Caesar Creek, Ohio. Collected by Bianca Hand.
context_page_description: This list of prehistoric echinoderms is an attempt to create a comprehensive listing of all genera that have ever been included in the Echinoderms that have been preserved as fossils. This list excludes purely vernacular terms. It includes all commonly accepted genera, but also genera that are now considered invalid, doubtful, or were not formally published, as well as junior synonyms of more established names, and genera that are no longer considered echinoderms.
  The list includes thousands of genera.
  Extinct genera are marked with a dagger.
  Extant genera are bolded.
context_section_description: †Xandarosaster
  †Xanthamphiura
  †Xenaster
  †Xenechinus
  †Xenoblastus
  †Xenocatillocrinus
  †Xenocidaris
  †Xenocrinus
  †Xenocystites
  †Xinjiangoblastus
  †Xisoallogecrinus
  †Xyeleblastus
  †Xysmacrinus
  †Xysteria
caption: Xenocrinus baeri (Meek, 1872); Upper Ordovician crinoid calyx from the Bull Fork Formation, Caesar Creek, Ohio.
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