ANISOGAMY IN THE DINOFLAGELLATE NOCTILUCA

We disagree on the generally accepted elements of the description of the sexual life cycle of Noctiluca as presented by Zingmark (1970a), namely that (1) the swarmers of Noctiluca are isogametes, that (2) the zygote develops directly into a large trophont, and we question that (3) Noctiluca is a diplont with meiosis occurring during the formation of the swarmers. We observed a highly distinct attraction between swarmers (microgametes?) and certain large cells (macrogametes?) which resemble adult trophonts in shape and size. Noctiluca thus appears to be anisogamous, and the zygote does not need to grow to become a large trophont.