Tropopause disappearance during the final months of the Antarctic winter, and the large annual range (35°C at 15 km.) of stratosphere temperatures, as revealed by 190 radiosonde ascents during 1940–1 at Littie America III, the West Base of the U. S. Antarctic Service, are not paralleled in the Northern Hemisphere and indicate that the Antarctic atmosphere has little exchange of air with the rest of the world. Other evidences of divorce from the world circulation are the coldness of the Antarctic troposphere compared to the Arctic, lower oxygen content of the Antarctic air than that of the rest of the world, asymmetry in world ozone distribution, and the general low pressure prevailing throughout the Antarctic.