Dosinia discus Reeve, 1850
Disk Dosinia is a hard-shell clam. The bivalve halves are compressed — that is to say, “ flattish” — rather than convex. It is white, with many fine, closely-spaced, concentric ridges on its orbicular surface. Traces of its thin, scaly, yellowish periostracum may remain on the surface of the bivalve. There is a prominent beak (the pointy part of the shell at the hinge). Disk Dosinia may reach a diameter of 3 inches.
It is found on the Southeastern coast of the United States, from Virginia to Florida and Texas, and the Bahamas.
Note: Dosinia elegans is a very similar-looking species, but that bivalve shell is a little less compressed, slightly smaller, and its concentric lines are not as closely spaced.