- 26 - feeding clam, feeds on bottom material, which is about 10 times that of plankton. The land-inhabiting hermit crab, Coenobita, and the coconut crab, Birgus, were intermediate in their general level of radioactivity between spider snail and giant clam. As shown in Table 5 and Figures 8 and 6, rates of decline as expressed on logarithmic paper varied from -0.9 for spider snail muscle to -2.8 for hermit crab liver, and averaged -1.75. Negative Slopes of Decline Rate of Invertebrates Logarithmically Graphed in Figures 5-10, Based on First and Last Observations Liver Kidney Entire 1.9 Sea Cucumber Coral 0,9 ~ © 1.4 1.7 Spider Snail hp Integument 2.0 Giant Clam —~ content 1.3 on Muscle Cut and Hermit Crab worn Coconut Crab Nw Tissue 1.7 2.0 Land Plants Collections of both edible and non-edible plants were made at Rongelap Atoll during the period from March 26, 1954 to October 21-23, 1955. In the last survey, the emphasis was placed upon those plant parts important in the native diet. These food items included coconut meat and milk and