The liver of Hooded Seal (Cystophora cristata) consists of six lobes of unequal sizes. Extensive sampling by means of cutout samples covering the depth horizon 2-30 mm below liver surface indicates that the liver may be considered homogeneous as to concentrations of zinc, cadmium, mercury, and selenium (residuals of overall mean compatible with normality, the all-organ variance negligibly in excess of within-lobe variance). Mercury and selenium are present in equimolar concentrations. Cutout samples have mercury and selenium concentrations respectively c. 17 and 8% (dry weight basis) above those of homogenates of the same lobe. The apparent dilution of mercury and selenium is tentatively attributed to coarse blood vessels and bile ducts abundantly present in the homogenate but almost absent from the cutouts.