Dictionary
eu•ryp•ter•id
Pronunciation: (yoo-rip'tu-rid, yu-), [key]—
n.
any aquatic arthropod of the extinct order Eurypterida, from the Paleozoic Era, closely related to trilobites and scorpions.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.