Shell of the Week: The Bicolor Purse Oyster
The Bicolor Purse Oyster, Isognomon bicolor (C.B. Adams, 1852), has an oval, very flat shell, with thin-walled valves and coarse, wavy, blade-like lamellae. The shell can reach 40 mm (about 1.6 inches.) Internally the shell has a small nacreous area, the non-nacreous area is wide, and the hinge in juvenile shells has a set of ridge-like teeth. This species is known to grow on rocks and hard structures in many areas of the Florida Keys. The complete shell in the illustration w