• (n.) A genus of crinoids belonging to the Blastoidea. They have five petal-like ambulacra.
extinct genus of stemmed, immobile echinoderms (forms related to the starfish) abundant as marine fossils in rocks of the Carboniferous Period (from ... [1 related articles]
Pen`tre·mi'tes noun [ New Latin , from Greek ... five + Latin remus an oar.] (Zoology) A genus of crinoids belonging to the Blastoidea. They have five petal-like ambulacra.