peristome

Etymology
From.

Noun

 * 1)  One or two rings of tooth-like appendages surrounding the opening of the capsule of many mosses.
 * 2)  The parts of or surrounding the mouths of numerous invertebrates.
 * 3) The lip, or edge of the aperture, of a spiral shell.
 * 1) The lip, or edge of the aperture, of a spiral shell.
 * 1) The lip, or edge of the aperture, of a spiral shell.

Derived terms

 * peristomate