Abstract
Many metallic elements are concentrated by marine animals to levels far in excess of their concentrations in sea water itself. This concentration extends not only to those elements which are known to have biochemical functions, but also to others which have no established biological role (e.g. cadmium and lead). Little is known about the mechanisms by which trace elements are concentrated, or about the manner in which they are held in the tissues. As a preliminary to the investigation of concentration mechanisms, reliable data are required concerning the distribution of the elements in a variety of marine animals.