Changes in phospholipids of plasma r .embranes and total particulate membranes of the cellular slime mold Dictyostelium discoideum were analyzed during development. The predominant classes of phospholipids in the plasma membrane were phosphatidylethanolamine and phosphatidylcholine, constituting approximately 50 and 25 molar per cent of phospholipid phosphorus, respectively. The relative amount...