- 10 - Radiobiological Studies of the Contamination of Eniwetok and Bikini Laboratory studies of a limited scope have been conducted at the Applied Fisheries Laboratory to support the field projects at the Pacific Proving Ground. These experiments include physical, biological and chemical studies. A. Uptake of fission products byalgae Experiments on the fate of fission products ingested by crabs eating radioactive Ulva lactuca or Nereocystis leutkeana indicated that most of the activity in the crabs was found in the digestive glands (51 per cent), and that the feces con- tained 42 per cent of the activity over a period of 17 days. The remainder was present in the gills, During the year, muscles, and carapace. reports will be written on the above experiments and on the work done with uptake of fission products from Engebi sand (1952) by algae. Experiments with the green alga, Chlorella pyrenoidosa, to determine whether it absorbed the activity rather than adsorbed it onto its surfaces, were conducted. In 30 seconds incubation in “hot" solutions dead algae killed by heating or by trichloroacetic acid retained as much activity as did live algae; however, with increasing incubation time, the living algae accumulated much more activity whereas the dead cells