High resolution image of the collecting canal of the contractile vacuole complex. Normally the collecting canal is expanded when the CV is in systole. In this micrograph the collecting canal is empty so that its two sides are flattened against each other. Presumably the CV is in diastole (filling phase). The ribbon of microtubules is split into 10 groups of two tubules each so the ribbon has 18 to 20 microtubules at this level. The smooth spongiome is connected to the collecting canal and bundles of decorated spongiome form the peripheral layer of the radial arm. The decorations consist of 2 closely set globular units forming a helix around the tubule. In this micrograph the globular units are outlined with more electron dense material so it appears there are 3 threads making up a helix. TEM taken on 12/9/70 by R. Allen with Hitachi HU11A operating at 75kV. Neg. 24,000X.The raw film was scanned with an Epson Perfection V750 Pro. This image is best used for quantitative analysis. Standard glutaraldehyde fixation followed by osmium tetroxide, dehydrated in alcohol and embedded in an epoxy resin. Microtome sections prepared at approximately 75nm thickness. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).