Top side of limestone (19 cm long) found in intertidal waters.
The above picture and the one following it show how effective chitons can scrape a rock-hard surface. The pictures show two sides of the same chunk of rock. The unscraped side never had a chiton living on it, whereas the scraped side shows how effective the grazing of a chiton can be. This is an excellent example of bioerosion. This chunk of rock came from Palau, in the South Pacific, and the scrape marks were made by another genus of chiton (chitons?), other than Cryptochiton.