-16- this simplification not only made it possible to avoid the debris from the ship and the almost inevitable leakage at the bayonet-type fitting of the plankton bucket, but also expedited the processing, it is recommended that this technique be used where radioassay is the primary objective. For laboratory processing of the March 1958 samples, the plankton was filtered and the preservative fluid was tested for radioactivity (practically lacking) before discarding, thus excluding most sea salt which might inadvertently have been included with the sample at the time of preservation. The August 1958 samples, including preservative, were evaporated to dryness, so that the sample from Station 7, including salt water accidentally used for washing the plankton bucket, appeared low in radioactivity!, Bottom samples were ashed and counted at Seattle in methane-flow counters. Plankton data after 1956 are presented as of the date of counting, rather than being corrected back to date of collecting as was done for the 1954-1955 material. It is probable that if corrections for decay could have been applied to the 1956 plankton data the levels on the date of collection would have been found to be about twice as high as those here given for the date of counting, but data from later collections would have been practically unaltered. 1The careful work of Dr. Remzi Geldiay at Seattle in processing the plankton samples of the August 1958 collections is gratefully acknowledged. erik weg ad lye pu re ew eee