Dendryphiella salina was grown in a sea-water nitrate medium with the following specifically labelled carbon sources: [1-14C]-, [2-14C]-, [6-14C]-glucose, [1-14C]-ribose and [1-14C]-glycerol. The data for distribution of 14C in polysaccharide hydrolysable with 1.0 N H2SO4 indicate that much of it is produced directly from glucose but there is confirmation of other studies that some is synthesized from mannitol. The distribution of label in arabitol is consistent with synthesis from ribose via xylulose. High activity is consistently found in carbon 3 of arabitol which is only explicable in terms of randomization in glycerol and the transketolase exchange reaction previously demonstrated to occur in rat liver.