In recent years several extensive collections of West Indian Decapod Crustacea have been received for identification by the Rijksmuseum van Natuurlijke Historie. On various visits to the Netherlands Antilles Dr. P. Wagenaar Hummelinck, Curator of the Zoological Laboratory at Utrecht, collected numerous Decapoda including many most interesting forms. Dr. J. S. Zaneveld, Director of the Caribbean Marine Biological Institute at Curaçao, not only assisted Dr. Hummelinck on his last (1955) visit to that island, but also sent in to the Rijksmuseum van Natuurlijke Historie important material which he had collected before and since; furthermore, during my own stay in the Netherlands Antilles (November 1956 to April 1957), Dr. Zaneveld did everything in his power to enable me to get together a fully representative collection of Decapoda of the region. Important material of Decapoda from St. Eustatius was received from Mr. P. A. van den Heuvel, Oranjestad. Through the kindness of Dr. D. C. Geijskes, Director of the Surinaams Museum at Paramaribo, Suriname, the Decapoda collected by the trawler “Coquette” during trawling experiments off the coast of Suriname were placed at my disposal. In all of these collections the genus Calappa is well represented. A study of this Calappa material revealed that until now at least three species have been confused under the name Calappa flammea (Herbst), and that a fourth species of the flammea-group occurs off the Suriname coast. Furthermore some interesting observations on Calappa sulcata Rathbun could be made.