Ultrastructure and Differentiation of Hydrodictyon Reticulatum I. Mitosis in the Coenobium

Abstract

Newly developed processing techniques have made possible an ultra� structural study of mitosis in the coenocytic green alga, H. reticulatum. Centrioles, apparently persistent in the coenobia, replicated and migrated to the poles of the prophase spindle as microtubules appeared between them. A perinuclear envelope of endoplasmic reticulum enclosed the nucleus, centrioles, and cytoplasmic microtubules around the nucleus at prophase; it remained virtually intact until telophase.