18 the greatest likelihood of the presence of plutonium. The values given in Table 14, therefore, probably are maximum values for each type of sample. The ratios of 239,240__ Pu to 238 Pu approach 2:1 at Eniman I. and are about 15:1 in Bravo Crater. Bikini I. soils contained no detectable 238 ou, although they contained the highest concentration of 239,240), u of the samples analyzed. The presence of 239,240), and 20754 in goatfish viscera is consistent and probably results from direct ingestion of fine particles of sediment during feeding. The absence of 2385 in goatfish viscera as compared with the sediment merely reflects a low concentration of this radionuclide, below the limits of detection. Although none of the 1969 samples were analyzed for the X-ray emitter O3n4, this radionuclide was found in concentrations of 80 a/m/g dry weight in Bravo Crater sediment collected in 1967 (Beasley and Held, 1969). Nickel-63 is of particular interest as a tracer since it has a half-life of 92 years. In addition, the clam kidney accumulates 63u4, and is there- as it does 6000, ‘ 63... fore an indicator organism for the presence of Si. Another long-lived radionuclide, 1 ‘ 08m,s with a half-life of approximately 100 years, has been identified for the first time among the radionuclides at Bikini. This radionuclide was detected from the gamma-ray spectrum of the hepatopancreas of