INTRODUCTION The coral reefs of the Togian islands grow up as steep barrier reefs and atolls. Moreover small fringing reefs occur along the islands. The geological structure of the islands, as well as the history and morphology of the reefs are treated in a separate paper 1). I will here mention only one of the striking features of the reefs. The reefs are situated in a zone, famous for the unruffled calm and undisturbed quiet of the sea, because they are protected from the influence of both monsoons. In a curve from West to North they are sheltered against the North monsoon by the Northern arm of Celebes; on the South of this group the Eastern arm of Celebes breaks the influence of the South East monsoon, which, blowing across the Banda Sea is only faintly felt in the Gulf of Tomini (fig. I). Shingle ramparts are completely lacking on these reefs, nor do sand cays occur. And we cannot on the Togian reefs distinguish the different faciestypes which I described from the Batavia reefs and the Sper-