Irregularly elongated oval, often strongly arched toward left or right, very compressed, thin-walled, tan with pale purple wavy radial rays, more or less smooth, with weak flaky lamellations; interior nacreous area large, non-nacreous border thin. Florida, Bermuda, Bahamas, West Indies, Gulf of Mexico, Caribbean Central America, South America (Colombia, Brazil). Length 40 mm (to 82 mm). Note: Also known as Listers Purse Oyster.