Apical pore complex
The apical pore (or pores) plus usually two plates: a pore plate (PO or peripheral apical platelet), surrounding a cover plate (PI or inner closing platelet). In some dinoflagellates, especially the peridinialeans, the apical pore complex may include also the canal plate, which is ventrally situated, usually between the pore plate and the first apical plate (or rhomb plate). Apical pore complex designated by APC. Refer to Text-Figure 61.