Observations on the infrastructures of ANABAENA CYCADINAE and of root-nodules cells ofCYCAS REVOLUTA. — Light and electron microscope observations carried on the fine and ultrafine sections of root-nodules ofCycas revoluta, brought in evidence differences structural and infrastructural of cells. These differences concern mainly the modifications presented by reticulum endoplasmic which in middle-aged cells takes a fragmentary and vescicular aspect, and the mitochondria which, in the same cells, show short cristae starting by outside wall of the organul.