Abstract
Scanning electron microscopy reveals unique supraependymal cells in preoptic and infundibular recesses of 3‐ to 21 ‐week‐old monkeys. Most supraependymal cells are located on nonciliated areas, and characteristically have round bodies from which multiple branched processes extend. Surface spherules occur on cell bodies and processes. Processes exhibit local enlargements, interweave with processes from other cells, and penetrate underlying ependyma.