OFFICIAL USE ONLY percentage of mm°? in fish. Unlike localization in the liver of mammals, mn? was found distributed fairly uniformly among the tissues. The Co°° found in clams accounted for the major portion of the activity. (The ability of clams to concentrate 00°? selectively was verified by laboratory experiments. ) The ie reentage of caletum in the solis that is available to the piants is not known. The Sunshine Units reported ere on the basis that all of the calcium is available. This provides a base line until better knowledge is gained but itisrecognized that thecorrectvalue for Sunshine Units probably are one to two orders of magnitude higher. — OFFICIAL USE ONLY 9002120