VESICLES OF TOROIDAL TOPOLOGY - OBSERVED MORPHOLOGY AND SHAPE TRANSFORMATIONS

We report observations of toroidal vesicles with circular and noncircu lar cross sections, axisymmetric and nonaxisymmetric. Shape transforma tions induced by temperature changes are also described, which permit a connection to a mathematical conjecture due to Willmore. Our observa tions are analysed using a numerical procedure which allows a determin ation of the relevant geometrical parameters of the shapes. We compare these observations with recent theoretical predictions and point out some unexpected properties of the observed equilibrium shapes.