High resolution image on the multiple membrane systems at the cortex of ciliates. Thickened alveolar densities partially coat the alveolar membrane within the alveoli which underlie the plasma membrane of ciliates. The densities are seen particularly along the inner membrane at its corners with the septa. Fibrous systems lie within the cytoplasm next to these densities. Cross sections of four cilia are also seen. Standard glutaraldehyde fixation followed by osmium tetroxide, dehydrated in alcohol and embedded in an epoxy resin. Microtome sections prepared at approximately 75nm thickness. TEM taken on 5/28/69 by R. Allen with Philips 300 operating at 60kV. Neg. 14,800X. The raw film was scanned with a Epson Perfection V750 Pro. This high resolution image is suitable for quantitative analysis. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).