The nascent phagosome membrane has a dense coat of acidosomes docked at its cytosolic surface well before the nascent vacuole pinches off the cytopharynx. This micrograph is a quick-freeze deep-etch image of a transverse section through the posterior portion of the buccal cavity with a nascent vacuole bulging from the cytopharynx. Living cells were spun down in a centrifuge and a slurry of cells was mounted on a copper support before slam freezing the living cells against a highly polished copper surface. Some paramecia had been disrupted and this cell was feeding on the particulate organelles of the disrupted cells. Thus the nascent vacuole contains these particles amassed against its luminal surface. The cilia in the buccal cavity obviously efficiently sweep the particles against the dorsal posterior surface. TEM taken on 5/26/92 by R. Allen with Zeiss 10A operating at 80kV. Neg. 4,000X. Bar = 1µm. Published in J. Cell Sci. 106:411-422, 1993. Adapted with permission.