The tongue has three circumvallate papillae, arranged in a triangle ahead of the foramen caecum. Gustatory buds are found only on the walls of the vallate papillae and at the surface of the fungiform papillae. The gustatory cells contain acetylcholinesterase; the sustentacular cells contain no such enzymes. A subepithelial network of nerve fibers, containing acetyl-and butyrylcholinesterases is parallel to the surface of the tongue and extends into the connective tissue cores of all papillae. Numerous pleomorphic end organs are found below all four types of papillae. These abound in acetyl-and butyrylcholinesterases. The dorsal subepithelial blood vessels contain butyrylcholinesterase, and small amounts of acetyl-cholinesterase. The ventral aspect of the tongue has fewer nerve fibers and end organs than the dorsal surface does. The nerve fibers to the serous glands of von Ebner, and particularly those to the mucous glands contain considerable acetylcholinesterase.