Erratum.
In the "NATO International Scientific Exchange Programmes" (31 Jan., p. 577), the item "Cell-free analysis of the functional organization of the cytoplasm" was listed incorrectly. The title should have been "Molecular mechanisms of membrane traffic." The organizer is Dr. Kathryn Howell, American Society for Cell Biology/NATO, 9650 Rockville Pike, Bethesda, MD 20814, USA. The date and place are 9-13 May 1992 and Virginia, USA, respectively.