Royal Society, January 28.
R. D. PRESTON and W. T. ASTBUBY: The structure of the wall of Valonia ventricosa. The cell wall of Valonia ventricosa has been studied in detail by means of X-ray diffraction photographs and the polarizing microscope. It consists of layers in which the cellulose chains in any one layer are inclined to those in the preceding and subsequent layers at an angle which is on the average rather less than a right angle. The chains of one set of layers form a system of meridians to the wall, while those of the other set build a system of spirals closing down on the two ‘poles' defined by the meridians. The development of the rhizoids is associated with regions of the wall adjacent to the poles of the spiral. The plane of spacing, 6-1 A., of the cellulose crystallites is, roughly speaking, confined within an angle of about 60 ° to the wall surface. The path of the cellulose spiral is that of a logarithmic (equiangular) spiral described on the surface of a sphere or prelate spheroid.