Accumulation of calcium, cadmium and mercury by isolated hepatocytes of the small skate (Raja erinacea) and rat was examined at 14 and 37 degrees C, respectively. 2. Metal uptakes by both species were biphasic, with rat cells accumulating more metal than the skate cells. 3. Total accumulation after 30 min was in the order: mercury = cadmium much greater than calcium. 4. In both species calcium and cadmium accumulations were reduced at 4 degrees C, while mercury accumulation was not. 5. Cd accumulation was increased by Cu and Hg in both species. 6. Hg accumulation was inhibited by Cu in both species, and increased by Cd only in the rat cells.