Stylodinium (style-owe-din-ee-um) is a rather unusual dinoflagellate, in which one phase of the life history is as a stalked and unflagellated cell - as here. Other forms include cysts, flagellates and heliozoan like organisms. The dinoflagellate nucleus with its condensed chromosomes is seen upper right. The circular structure is /are starch deposits around a pyrenoid. Probably related to Pfiesteria, a genus gaining (undue?) significance for its potential as a source of fish killer. Differential interference contrast.