noun
A fossil blastoid echinoderm of the mostly North American genus Pentremites, having five spiracles surrounding the mouth.
Origin
Mid 19th century; earliest use found in Transactions of the Geological Society. From scientific Latin Pentremites, former genus name from penta- + ancient Greek τρῆμα hole, aperture + scientific Latin -ites, with omission of the second syllable, -ta-.
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