Paramecium also contains many crystals in older cultures. This micrograph is of a crystal taken from a cell in stationary phase (day 8 post-inoculation). Crystals are enclosed by a membrane and contain sheets of paracrystalline material similar to that in lysosomes and phagolysosomes that lie just inside the membrane. The crystal membrane has a pronounced glycocalyx like phagolysosomes and lysosomes and may store digestive enzymes in a paracrystalline form during periods of starvation or limited food supply. TEM taken on 3/6/80 by R. Allen with Hitachi HU11A operating at 75kV. Neg. 10,250X. Bar = 0.5µm.