‘ Fre - 3 * geometry of the counter (about 15%) were approximately 10,000 per ainute per gram, Readings on the Victorsen survey meter, Model 263, of the mad after it was placed in the aquaria, but before the water was re~- placed were as high as 12,5 on the 1 scale which is roughly translated to 8 r per day. Two days after the aud was added to the aquarium, April 3rd, some md could stili be seen in suspension in the water. A 5 ml. sample of water at that time gave a count of 5 per minute uncorrected for geometry (approximately15%). / The flatfish placed in the Bikini mud aquarium on April ist died on April 7th. Ashed samples of the gill, macle, skin, bone, digestive tract gave no count above background. This fish fed the first three days tt not the last four, The suspension of the fine mad particles in the water probably was a factor causing death. The dead fish was immedi ately replaced by one from the supply tank and has fed regularly since then to the present, (May 3rd). By April 10th the water in aquarium #2 was clear, This may be due in part to the fast that the clam placed in the aquarium at the same time as the fish died on April 9th, digestive tract were ashed and counted, Clam samplea of gill and There was no count in the gill sample and about 5 counts per gram in the digestive tract sample which could have been due to particles of md in the digestive tract rather than activity in the tissues, The clam was not replaced, The alga, Ulva sp., commonly known as sea lettuce, that was placed in aquarium #2 on April lst was removed and counted for activity on April 23rd. It was mostly covered with Bikini mud so was washed and rinsed several times to remove all md particles, This was done by washing carefully by hand under running water. | DomARCHIVES