Abstract
The fine structure of some sixty different collections of blue-green algae representing at least thirty different species was studied. In addition to the usual components of blue-green algal cells, a number of different, unique, intracellular structures were observed. Membranous “stacks”, and “spheres”, and “scrolls” in which the membranes are not typical unit membranes are described. “Spheroids”, 25 to 30mμ in diameter, were found in intrathylakoidal spaces of several collections. Other inclusions, including a variety of filamentous and crystalline arrays, are described. It is suggested that some of these inclusions are intracellular symbionts.
