Vanhyning's Heart Cockle
Dinocardium robustum Vanhyningi Clench & Smith 1944
This bivalve, found on the west coast of Florida, is a pretty specimen. Its outline is more or less like a lopsided triangle as you look down at the exterior of the shell, though the ribbed shell is well-inflated. It can be over 5 inches in length and has distinctive chestnut-colored bars on its yellowish-tan-white surface.
Decades ago this kind of shell was sold as an ashtray with a beach or town's name written on it.