in natural history, the petrified teeth of the lupus-piscis, or wolf-fish, frequently found fossil. They are of different shapes; but the most common kind rise into a semiorbicular form, and are hollow within, somewhat resembling an acorn-cup; this hollow is found sometimes empty, and sometimes filled with the stratum in which it is immersed. Many of them have an outer-circle, of a different colour from the rest.