the petrified teeth of the lupus-piscis, or wolf-fish, frequently found in a fossil state. They are of different shapes; but the most common kind swell out in a semi-orbicular 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 was imbedded. Many of them have an outer circle of a different colour from the rest.