Observations on organized areas of the endoplasmic reticulum, mitochondria, and ribosomes in ependymal cells of the subcommissural organ of Cebus, Saimiri and Callicebus (Platyrrhina, Primates).

The endoplasmic reticulum, the distribution of ribosomes attached to its membranes and the topographic relation of mitochondria have been studied in ependymal cells of the subcommissural organ of Cebus, Saimiri, and Callicebus. Occasionally, these organelles appear to be distinctly organized in restricted areas. They may be either irregularly arranged, formed into stacks, or organized into individualized corpuscules. The constituents of these organized areas are the same. Topographic relations with the GOLGI apparatus which would indicate a close interaction between these organelles, were not observed. The assemblage of substructures known to be involved in the synthesis of secretions of the subcommissural organ indicates a specific function of those areas.