The Southern Marsh Clam
The Southern Marsh Clam, Polymesoda floridana (Conrad, 1846), is a species of bivalve mollusk found locally, mostly in the back-bay areas, including the Caloosahatchee estuary and mangrove habitats. This species has a broad tolerance for changes in salinity. Its adult shell measures from 1 to 1.5 inches; the shell is roughly triangular, with rounded ventral (bottom on the photos) and pointed posterior (left on photos) margins. The shell sculpture is restricted to irregular gr