Accumulations of acidosome-like vesicles are sometimes found (in this case in a predividing cell) and in this micrograph provide further evidence for invaginations of the outer membranes. It appears to me that these vesicles are more likely multivesicular bodies that have internal vesicles and are known to be late endosomes. When compared to Paramecium these vesicles are equivalent to acidosomes which also have invaginations and are responsible for the transfer of V-type proton pumps to the digestive vacuole. TEM taken on 8/14/67 by R. Allen with Philips 200 operating at 60kV. Neg. 12,400X. Bar = 0.5µm. The negative was printed to paper and the image was scanned to Photoshop. This digitized image is available for qualitative analysis. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).