Ciliate, edged with parallel hairs, bristles, or appendages, like the eyelids.
Cinereous, of ash colour, of the colour of wood ashes.
Clavate, club-shaped, thicker towards the top, elongated towards the base.
Cochleæ, shells of one piece, univalves.
Cochleate, twisted like a screw or the shell of a snail.
Columella, the upright pillar in the centre of most of the univalve shells.
Commissure, a joint or seam.
Complicated, doubled together.
Compressed, perpendicularly squeezed together, in opposition to depressed, which is horizontally flattened.
Concamerated, arched over, vaulted.