Coencbita perlatus, from this island. Collections were made at approxi- mately daily intervals commencing with the third day following the Nectar c test until the ninth day and thereafter at lengthened intervals until approximately monthly intervals. years after the test. Sampling continued until about two Strontium-89 and -90 were detected in the exoskeletons and other parts of the crab. The amount in the exoskeletons remained at a nearly constant level, excepting nuclear decay. Levels of activity, three days after the Nectar test were a high of 5 million d/min-g in the gut, but at the end of the two years were typically about 10 thousand d/min-g (Held, 1960). . | The first large-scale land-based study of residual radioactivity was" in 1964 by the Laboratory of Radiation Biology of the University of Wdsuingion. The study was &t Caiwetok, Bikiai, dad Rougelap Atolls. This was eight years after the last test in this area of the world, and so allowed observation of long-term effects of nuclear detonations (Welander et al, 1966). Hundreds of specimens of a broad range of organisms were collected for radioanalyses and later evaluation at the University. External radioactivity was measured by beta-gamma survey meters at three feet above ground level. Following are some of the observations: External Radiation in mR/hr - Island Runic (Yvonne) Rigili (Leroy) Bogombogo (Belle) Engebi (Janet) Average ., Maximum 0.13 0.04 9.80 1.0 (Near craters at north) 0.23 0.22 0.70 22