For comparison with cesium-137 levels, value for each collection is given in Table 1. the average potassium The average potassium value for all samples was 13.05 mg/g with a standard deviation of 3. 66. The range in values was 2.96 to 21.2 mg K/g dry weight, but 83 per cent of the 30 samples analyzed fel) in the range of 10 to 15 mg K/g dry weight. The two lowest values of 2.96 and 3.48 mg K/g dry weight ap- pear to be completely out of line. samples gave essentially the Repetition of the analysis of these same results and no explanation for the disparity is offered. A significant difference in potassium levels associated either with island or season of collection is not apparent (March falls in the dry season and August in the wet season). Nor is there any correlation be- tween potassium and cesium-137 levels at any one island. In this regard, the data should not be pooled since it has been established that there are differences in cesium-137 levels from island to island. The regression of cesium-137 on potassium in the crab muscle, as determined in the largest Sample from Kabelle Island, indicated no relation between these elements. Cesium-137 levels have been reported as cesium units, micro microcuries of cesium-137 per gram of potassium ( U. S. AEC reports fallout). This unit is based on metabolic similarity of cesium and potas- sium and is used to facilitate in a on manner Libby (1956). similar to the comparison of different types of materials use of the strontium unit adopted by Anderson, Schuch, Fisher and Langham (1957) have used ge