Objective To explore the structural foundation of transport pathway of pineal secretions from the pineal body to the cerebrospinal fluid of subarachnoid space. Methods The pineal capsule of the superficial pineal body of 15-month and 12-month old rats was observed under scanning electron microscope(SEM). Results Cribriform and trumpet-shaped epithelial stomata were scattered on the pineal capsule.Cribriform epithelial stomata were seen mostly in 15-month old rats.They were composed of many round pores which pierced through the full-thickness of the periphery of the capsule endothelium.The pores were dense and ranged from 200-500 nm in diameter;trumpet-shaped epithelial stomata were seen in both 1-5month and 12-month old rats.Trumpet-shaped epithelial stomata were located among epithelial cells of the pineal capsule.They were round or elliptic in shape and ranged from 1-4 μm in diameter.On the surface of the pineal capsule,many secretory granules were observed.They were spherule and 8001 000 nm in diameter.Conclusion The releasing pattern of secretory granules of the pineal body could include a releasing of the whole membrane; the pineal secretions may be transported directly from the pineal body to the cerebrospinal fluid of subarachnoid space throu