“…Galleron and Durrand noted (p. 162) that Amphidinium carterae does ex hibit "distinct S, G2, and M phases" of the cell cycle. The exact nature of the synthesis is still to be determined; however, Galleron and Durrand have begun to probe this problem using After reviewing the present literature on dinoflagellate cell cycles one can summarize by noting that five studies advocate a discrete period of DNA synthesis corresponding to an S phase in the cell cycle (Franker, 1971;Franker et ai, 1974;Loeblich, 1976;Spector et ai, 1981;Sweeney, 1981), two studies suggest that DNA synthesis is continuous and reminiscent of prokaryotic synthesis (Dodge, 1966;Filfilan and Sigee, 1977), and the re maining report, by Galleron and Durrand (1979), demonstrates that an S phase is present but residual incorporation of label occurs at other stages of the cell cycle as well. Like P. micans (Filfilan and Sigee, 1977), Amphidinium also exhibits a continuous low level of DNA synthesis.…”