supervised the work in his field of specialization and summarized the results for inclusion in this group report. Dorothy South was responsible for doing the chemical analyses on selected specimens of sand, soil and biological samples. The work on absorption and decay curves was handled by Paul Olson. 2.1 Areas Sampled The locations of the collecting stations are shown in Figure 1. There were 7 major stations, 6 of which were approximately the same as those visited in 1948 and 1949 and the 7th, Bogombogo-Bogallua, was 2 to 3 miles west of the Mike test shot island. The same areas from which collections were made before the test were revisited after the test where circumstances allowed. Collections of fish, invertebrates and algae were generally made on the lagoon side from the intertidal zone down to a depth of about 12 feet. Occasionally the sampling area was extended to the ocean side of the collecting station, especially if there was a scarcity of specimens on the lagoon side. Terrestrial plants and animals were gathered from the islands and, while the reef and island collections were being made, plankton towing, dredging and water sampling operations were being carried on in contiguous waters. These operations on occasion extended 2 or 3 miles from the area of reef collections. ~4e /2