The Circular Chinese Hat
The Circular Chinese Hat, Calyptraea centralis (Conrad, 1841), is a close relative of the more commonly found Slipper Snails. The half-inch species is a gastropod, albeit one with a cap-shaped, circular shell that could easily be mistaken for a little white clam valve. The shell "aperture," on the bottom is represented by a sinuous ("sigmoid"), flaring shelf inside shell. The shell color is invariably white.
The Circular Chinese Hat, Calyptraea centralis, from Sanibel Island. Photo by José H. Leal.