Dictionary
an•as•pid
Pronunciation: (u-nas'pid), [key]
—n. Paleontol.
any member of an extinct order, Anaspida, of small, freshwater jawless fishes of the Silurian and Devonian periods, characterized by a single nostril, narrow rows of scales, and, usually, an armor-plated head.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.