In Opercularia coarctata specialized ER modified into decorated tubules lie on the surface of myonemes. The composition and function of the decorations have not been determined but they may be calcium pumps or calcium channels. TEM taken on 6/6/69 by R. Allen with Philips 300 operating at 60kV. Neg. 11,800X. Bar = 0.1µm. A print of the negative was scanned and processed in Photoshop. This image is best used for qualitative analysis. A high resolution image (CIL:7662) is available 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/).