In the oligodendrocytes of cerebellum and spinal cord and in the Schwann cells of peripheral nerves of cat, albino mouse, and Japanese waltzing mouse lipopigment bodies of different size and shape are deposited, which exhibit a characteristic internal structure. The following three subtypes can be distinguished: (1) Granules completely surrounded by a membrane and containing regularly speced lamellae, (2) granules consisting of a granular matrix with elucidations, and (3) granules with bifurcating stacks of lamellae. Thus, their structure is distinct from that found in nerve cells and other glial cells and allows the diagnosis of oligodendrocyte or Schwann cell. The significance of these granules in relation to function and aging is briefly discussed.