The process of regeneration of Candida utilis and Pichia polymorpha protoplasts obtained by means of an enzyme preparation from Streptomyces violaceus M R and an enzyme preparation from the snail (Helix pomatia) was followed with the electron microscope. A reticular network of fibrils making up a tube or surrounding the regenerating protoplasts was observed. The fibrils are glucan fibrils, and in C . utilis they are packed in groups of 5 or 6. P. polymorpha fibrils occurred singly. The fibrils are the framework for building the new cell wall. The relation between fibrils and plasmalemma particles is discussed.