The fine structure of marginal band microtubules

Abstract
Fixation of Fundulus erythrocytes by silver acetate‐osmium tetroxide solutions preserves marginal band microtubules while extracting the obscuring hemoglobin background. High magnification electron micrographs of thin sections show the microtubules to be composed of globular subunits. Cross‐sectional profiles of the microtubules contain six or seven subunits. The discussion includes comments as to the general stability of microtubular structures, and to the similarities between microtubules and tobacco mosaic virus protein.