A high resolution view of the contractile, sub-cortical myonemal sheet of Opercularia coarctata. Decorated ER tubules 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. 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 6/13/69 by R. Allen with Philips 300 operatinjg at 60kV. Neg. 14,800X. The raw film was scanned with an Epson Perfection V750 Pro. This high resolution image is available for quantitative analysis. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).