While I was in Europe in the summer of 1897, it was my good fortune to meet Prof. K. MARTIN, Director of the Leyden Geological Museum, who upon hearing that I was making a special study of West Indian fossil corals, kindly offered to place at my disposal the specimens that he had collected in the Dutch West Indies. Hon. CHAS. D. WALCOTT, Director of the United States Geological Survey, has permitted me to study this material and write a report upon it. The principal object of my journey to Europe during the last International Geological Congress was to visit and study collections bearing upon our American fossil corals. Type collections of a good many of the species discussed in this paper were examined, and it is my pleasant duty here to make acknowledgements for courtesies extended to me at several museums. Dr. WILHELM WELTNER, Custos in the Museum für Naturkunde at Berlin, was very kind to me, and enabled me to study all of EHRENBERG’S types from the West Indies. I also examined some of KLUNZINGER’S types. Prof. CAMERANO at Turin, gave me every facility for studying such types of DUCHASSING and MICHELOTTI as are preserved there. The assistants of Prof. EDMOND PERRIER permitted me to study a considerable amount of the material of MILNE-EDWARDS and HAIME in the Museum d’Histoire Naturelle at Paris. Dr. HENRY WOODWARD and Dr. GREGORY gave me every facility for studying the fossil corals in the British Museum of Natural History; and Prof. F. JEFFREY BELL and Mr. H. M. BERNARD gave me access to all of the recent corals that I desired to study in that institution. The officers of the Geological Society of London gave me all the assistance possible. I studied there most of the types of DUNCAN.