The acidosome-like vesicle has at least 2 enclosing membranes or one membrane indented back on itself and an internal electron-opaque tongue-like droplet that is continuous with the enclosing membranes at one end of the vesicle and may arise by invagination of these membranes into the vesicle’s interior. Such vesicles do not resemble lysosomes of any other organism, including Paramecium. Lysosome membranes should be thicker and be coated by a heavy glycocalyx and exhibit latency. There is no glycocalyx seen here. TEM taken on 8/15/67 by R. Allen with Philips 200 operating at 60kV. Neg. 19,200X. Bar = 0.5µm. The negative was printed to paper and the image was scanned to Photoshop. This digitized image is available for qualitative analysis. There is a high resolution version of this image in the library (CIL:39722) which is available for quantitative analysis. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).