Ancistrum is a marine ciliate that inhabits the mantle cavity of mytiliid mussels. This image shows a good view of the macronucleus, mitochondria with tubular cristae, and what are probably flask-shaped endosomes. This group of images is located in a part of the cytoplasm that especially contains these vesicles, and this image has a view at an appropriate angle to exhibit what may be dynamin or a dynamin-like protein decorating the tube of the flask shaped organelle. In addition, the macronuclear membrane is well demonstrated. TEM taken by G. Antipa in 1969 on a Hitachi HU11A operating at 75kV. 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 60nm thickness.