Chiton (Rhyssoplalx) olivaceus Spengler, 1797

This one and one-half inch chiton is oblong in shape and elevated. The color of the valves is quite variable: black, brown, scarlet or olive-green, sometimes clouded or mottled. The lateral areas are raised and sculptured with 4-6 radiating ribs. The central areas have a smooth triangle at the ridge of each valve, the sides having strong longitudinal ribs. The girdle is wide, banded with alternate light and dark and completely covered with minute, smooth convex scales. Taken from Pilsbry

Illustrated specimen is from the Burghardt Collection