SIXTEEN FIGURES
I n the Scleractinia, the larvae o r planulae have been investigated in only a few species, and only a few forms are known whose planulae settle down and grow well under laboratory conditions. Among such corals I have already reported on two species of the family Seriatoporidae, viz., Pocillopora danzicornis cespitosa (Dana) and Stylophora pistillata (Esper) (Atoda, '47a, b).
Acropora belongs in the family Acroporidae of the Scleractinia, while Pocillopora and Styloghora belong to the Seriatoporidae. Acropora briiggemanni (figs. 1, Z ) , proved to be excellent for the study of the behavior of the planulae of Acropora.
'The present work was accomplished through the financial aid of the Japan Society for the Promotion of Scientific Research, to which I wish to express my sincere gratitude. My hearty thanks are also due to Prof. Emeritus Shinkishi Hatai, the former director of the former Palao Tropical Biological Station where the work was done, f o r his kind guidance throughout the investigation and to the late Prof. Dr. Sanji Hozawa of the TGhoku University for giving me valuable advice, criticism, and stimulation. Acknowledgements are due to Dr. Preston E. Cloud of the United States Geological Survey, for preliminary editing, and to Dr. John W. Wells of Cornell University for later revision, of the manuscript. Further, I am much indebted (to Dr. Eotora Hatai of the T8hoku University and) to Director Akira Noguchi of the Second High School for his encouragement.