- 14 -~ species ingest bottom material indiscriminately and that they migrate very little. Activity of approximately six disinte- grations per minute per gram (d/m/g) dried soil was found in Rigili and Runit soil and 30 d/m/g in that from Rojoa, and from four to 200 d/m/g in the sea cucumber intestine contents. This work will soon be published as an Applied Fisheries Laboratory report. Other projects included the development of a technique for separating trace quantities of radiostrontium from large amounts of ashed biological material or sand from the Pacific area and the analysis of well water used in the School of Fisheries experimental hatchery. D. Studies of the Marshall Islands fishes A good deal of work was done with fishes of the Marshall Islands in preparation for the studies at Bikini and Eniwetok this year. A field key for rapid identification at the Eniwetok laboratory of over one hundred species which are most abundant on the reefs was prepared and taken to the Pacific laboratory. Also, an improved fish sampling program was organized for the investigations at the field laboratories. A paper on fishes of the Marshall and Marianas tslands!”), with one of the Laboratory staff members as co-author, was published by the Smithsonian Institute, United States National Museum, in November 1953.