ULTRASTRUCTURAL OBSERVATIONS OF GYRODINIUM ESTUARIALE (DINOPHYCEAE)1

Gyrodinium estuariale Hulburt has ultrastructural features typical for a dinoflagellate including a particularly well developed pusule and numerous prominent trichocysts. The amphiesma is relatively simple with thecal vesicles containing thecal membranes. The epicone is embellished with two concentric raised ridges reminiscent of the form typical for more heavily thecate genera.