THECAL ULTRASTRUCTURE OF THE TOXIC MARINE DINOFLAGELLATE GONYAULAX CATENELLA1

The toxic marine dinoflagellate Gonyaulax catenella Whedon & Kofoid was studied with scanning and transmission electron microscopy to describe the thecal morphology and to accurately define the taxonomic characters of the species. The closing platelet which lies in a U-shaped apical pore was revealed to be disassociable from a partly obscured apical platelet. Two previously unreported sulcal plates were charaterized and described. The entire complement of thecal plates numbered 33.