A view of the endosymbiotic Chlorella of a green Trichodina that lives on the surface of a freshwater snail collected in central Illinois. In this image there is also an endosymbiotic bacterium. It has the profile of a U at the lower left. Other images of the green Trichodina (i.e CIL:25691 & 25688) show endosymbiotic bacteria full of viral particles. TEM taken by G. Antipa in 1968 on a Hitachi HU11A operating at 75kV. The original image was taken at 12,500X, and 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 65nm thickness.