112 D. A. RHINEHART 



side, supply this structure. These fibers form a plexus exter- 

 nal to the valley and within the core of the papilla. From these 

 plexuses fibers supply the taste-buds and* the epithelium of the 

 papilla and the surrounding mucous membrane. In two series 

 a microscopic ganglion is present within the papilla. 



The most lateral of the five branches of the glossopharyngeal 

 nerve extends anteriorly along the lateral side of the tongue and 

 terminates in the foliate papillae. The other two bundles are 

 distributed to the tongue over an area extending as far forward 

 as a line connecting the anterior limits of the foliate and cir- 

 cumvallate papillae. 



The lingual nerve, because of the fibers in it from the facial 

 nerve, was carefully studied. From one transverse series a 

 graph of the course, branches, and distribution of this nerve 

 within the tongue was made, and all the branches, as far as pos- 

 sible, followed to their termination. 



From its union with the chorda tympani the lingual nerve 

 passes medially, ventrally, and anteriorly to reach the tongue. 

 It hes between the internal and external pterygoid muscles, then 

 between the internal pterygoid and the mandible, and finally 

 between the mylohj^oid and the side of the tongue. It curves 

 around the ducts of the submaxillary and sublingual glands, turns 

 anteriorly lateral to the genioglossus, and inclines dorsally into 

 the substance of the tongue. 



A few branches are given off from the lingual nerve before it 

 enters the tongue. At the ventral edge of the internal pterygoid 

 and under the mylohyoid muscle a number of small branches are 

 given off which pass posteriorly to the submaxillary and sublin- 

 gual glands. At the ventral edge of the internal pterygoid a 

 larger branch arises which passes medially to supply an area of 

 the mucous membrane of the cheek opposite the folliate papil- 

 lae. This branch sends fibers into the epithelium, into a mass of 

 glands, and into a number of taste-buds (eight in the series 

 studied). Along the side of the tongue, in relation to the gland 

 ducts, one relatively large and a number of smaller branches are 

 given off which pass forward in company with the ducts and 

 supply the mucous membrane of the floor of the mouth and the 

 gum behind the lower incisor teeth. 



