Pore located on the apical pore plate (Po). This feature is not always a round or oval hole, but can be long and narrow and/or curved, or even fishhook shaped. In Alexandrium spp. this pore is referred to as a foramen. If the apical pore is a hole, then it may have a closing/cover plate (cp) or canopy (e.g. Pyrodinium bahamense var. bahamense and P. bahamense var. compressum).

Alternative form for apical pore : ap.