The ganglionic sheath is structured upon a complex fibrocellular framework. A tridimentional network of anastomosed connective tissue lamellae constitutes the extracellular space. In the deep ganglionic region these lamellae display alkaline phosphatase activity. Sheath cells appear embedded in network fenestrae. The most peculiar of these are the superficial voluminous globular cells. Its cytoplasm appears built of a lipoprotein network containing glycogen and “lipofuscin pigments.” These two latter substances appear to undergo seasonal changes. The gland cells seem to be unicellular endocrine glands, containing many droplets giving positive reaction for carbohydrates, lipids and proteins. Muscle cells are placed throughout the sheath. The cytoplasm gives an intense reaction for proteins but does riot exhibit myofibrilles. These cells could play an important role in ganglonic movements and in addition could modify the amplitude of the extracellular sheath space. Pigment cells, containing melanin granules, are distributed among the other sheath cells. Cellular groups of the sheath show many large spheroidal mitochondria and sudanophilic droplets. These cells could be involved in the synthesis of some unknown substance or/and in metabolic transport across the sheath. Glial cells are located under the sheath and surrounding the entire neuronal surface. The cytoplasm appears connected with alkaline phosphatase and with an acidic substance. The histochemical and topographical characteristics of these cells point to their role in metabolic transportation, mechanical support and nervous homeostasis.