Madreporaria from the Bay of Batavia

INTRODUCTION In the Bay of Batavia there are patch-reefs and cays in different stadia of development. Some are small reefs still rather deep below sea level, other reefs bear a small sand cay. On the larger coral sand islands vegetation has developed ; moreover shingle ramparts and a moat have come into existence. The islands and reefs considered in this paper are situated South of a line which may be thought passing from Cape Pasir towards the Island Edam, so forming a boundary between the reefs in the Bay of Batavia and the northern group of Thousand Islands („Duizend eilanden"). The author studied these reefs in some detail and the results were published as early as 1928 1). In that amply illustrated paper data and considerations may be found on temperature, salinity, silt, beach conglomerate, negative shift of the strandline; special attention is given to the origin and development of the reefs and islands and the mutual connection between their morphology and the prevailing winds. Moreover a preliminary list of coral species was given and the ecological aspects were considered. (The corals figured in that paper are in the Museum of the Geological Survey at Bandoeng, Java). The two points last named are treated in a more definite form in the present publication. Since I published the 1928 paper I paid some more visits to the Bay of Batavia resulting in the finding of a greater number of species. Then a zoologist, Dr J. Verwey, stayed in Batavia a few years and made extensive studies on the fauna of the reefs 1). Also Boschma published some papers on corals from the Bay of Bata-