THE FINE STRUCTURE OF PROCHLORON

SUMMARY The fine structure is described of Prochloron, a unicellular prokaryotic alga which contains both chlorophyll a and chlorophyll b. The cell wall resembles that of a blue-green alga. The thylakoids and cytoplasm together occupy a wide peripheral band. However, the thylakoids are present not as single lamellae, as in blue-green algae, but in pairs or, sometimes, in thicker stacks. Both thylakoids and cytoplasm are absent from a large central zone which is generally electron-transparent, but may contain electron-dense granules and fibrils. The function of the central zone is not known.