portrait

Description:

Peridinium quinqucorne cells are diamond shaped to ovoid, with a pointed apex, and a number of projections from the hypocone, 20 - 25 microns long, 15 - 18 microns wide. Thecal plates present: an apical pore, a canal plate, 3 apical plates, 1 anterior intercalary plate, 7 precingular plates, 5 cinguluar plates, sulcal plates not known, 5 postcingular plates, 2 posterior plates. Small apical pore present, in a short apical horn. Cingulum 4 - 5 microns wide, number of plates not recorded. The large anterior sulcal plate forming a list over the left sulcal plate. Four spines (4-5 microns long) project from the antapical plates. Thecal plates smooth, with scattered pores. Intercalary bands may be wide on some cells. Nucleus round, in the centre of the cell, approximately 7 microns diameter. Reddish stigma, present near the beginning of the sulcus. Yellow- brown plastids, 2 - 3 microns diameter, scattered throughout the cell.