Abstract
Cingulum and valve morphology of the marine epizoic diatom Falcula hyalina Takano, collected from Choctawhatchee Bay, northeastern Gulf of Mexico, were studied with scanning electron microscopy. The cingulum is composed of four incomplete ligulate bands. The apical pore fields are interpreted as ocellulimbi. Its taxonomie relationships and ecology are discussed. This is the first record of F. hyalina from the Gulf of Mexico.