A view of the contractile, sub-cortical myonemal sheet of Opercularia coarctata. It is decorated with ER tubules that are intimately associated with the myonemal sheet. And pellicular pores or clathrin coated pits are evident in this grazing section through the periphery of the cortex. TEM taken on 6/13/69 by R. Allen with Philips 300 operating at 60kV. Neg. 14,800X. Bar = 0.5µm. A print of the negative was scanned and processed in Photoshop. This image is best used for qualitative analysis. A high resolution image (CIL:7343) 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/).