geometry of the counter (about 15%) were approximately 10,000 per minute per gram. Readings on the Victoreen survey meter, Model 263, of the mud after it was placed in ths aquaria, but »%efore the water was re- placed were as hich as 12,5 on the 1 scale which is roughly translated to 3 r per day, Two days after the mud was added to the aquariun, April 3rd, some amd sould still be seen in suspension in the water. A 5 mi, sample of water at that time gyre a count of 5 per minute uncorrected for geomatry (approximately 15%). The flatfish placed in the Bikini md aquarium on April ist diad on April 7th. Ashed sanples of the gill, mesle, skin, bone, digestive tract gave neo count above background. the first three days but not the last four, This fish fed The suspension of the fine mud particles in the water probably was 4 factor causint® death, The dead fish waa immediately replaced by one from the supply tank and has fed regularly since then to the present, (May 3rd). By April LOth the water in aquarium #2 was clear, This may be due in part to tha fact that tne clam olaced in the aquarium at the same tine as the fish died on April 9th. digestive tract were ashed and counted, Clam samples of gill and Thare 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 mdin the digestive tract rather than activity in the tissues, The clam was not replaced, The alga, Ulva 3p,, comnon.y known as sea lettuce, that was Placed in aquarium 72 on April lst was removed and counted for activity on April 23rd. It was mostly covered with Sikini mid so was washed and rinsed several times to remove all wd particles, This was done by washing carefully by and under running water. DO# ARCHIVES