Body scales in dinoflagellate species belonging to Heterocapsa developed in vesicles derived from the Golgi apparatus, but did not appear within the stacked Golgi cisternae. The membranes of the scale vesicles functioned as molds for the developing scales. Mature scales within expanded vesicles moved to the flagellar area, the site of release. Body scales were seen within the cytoplasm of Heterocapsa spp. fixed at various times in the light: dark cycle, suggesting that scales are formed and probably released continuously.