High resolution image of a myoneme of Opercularia coarctata. Such fibrous bundles are known to be composed of centrin, a filament that contracts when exposed to calcium. The ER is closely associated with the myonemes and sends specialized decorated tubules onto the surface or into the fibrous bundle. The peroxisome typically has one luminal tubule and mitochondria have tubular cristae. TEM taken on 6/13/69 by R. Allen with Philips 300 operating at 60kV. Neg. 30,200X. 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/).