PAPILLA OF TONGUE. 463 



calycifarmes. This cup-shaped cavity forms a kind of fossa around 

 ' tne papilla, whence their name circumvallatcc. 



At the meeting of the two rows of these papillae upon the middle 

 of the root of the tongue, is a deep mucous follicle called foramen 

 cacum. 



The Papillce conic ce and filiformes cover the whole surface of the 

 tongue in front of the circumvallatae, but are most abundant near its 

 apex. They are conical and filiform in shape, and have their points 

 directed backwards. 



The Papillae fungi formes are irregularly dispersed over the dorsum 

 of the tongue, and are easily recognised amongst the other papillae 

 by their rounded heads and larger size. A number of these papillae 

 will generally be observed at the tip of the tongue. 



Behind the papillae circumvallatse, at the root of the tongue, are a 

 number of mucous glands, which open upon the surface. They have 

 been improperly described as papillae by some authors. 



Vessels and Nerves. The tongue is abundantly supplied with 

 blood by the lingual arteries. 



The Nerves are three in number, and of large size: 1. The 

 gustatory branch of the fifth, which is distributed to the papillae, and 

 is the nerve of common sensation and of taste. 2. The glosso-pha- 

 ryngeal, which is distributed to the mucous membrane, follicles, and 

 glands of the tongue, is a nerve of sensation and motion ; it also 

 serves to associate the tongue with the pharynx and larynx. Pa- 

 nizza's experiments, tending to prove that this is the true nerve of 

 taste, are rendered questionable by recent experiments. 3. The 

 lingual, which is the motor nerve of the tongue, and is distributed 

 to the muscles. 



The Mucous membrane which invests the tongue, is continous with 

 the cutis along the margins of the lips. On either side of the fraenum 

 linguae it may be traced through the sublingual ducts into the sub- 

 lingual glands, and along Wharton's* ducts into the sub-maxillary 

 glands ; from the sides of the cheeks it passes through the openings 

 of Stenon'sf ducts to the parotid gland ; in the fauces, it forms the 

 assemblage of follicles called tonsils, and may be thence traced 

 downwards into the larynx and pharynx, where it is continuous with 

 the general gastro-pulmonary mucous membrane. 



Beneath the mucous membrane of the mouth are a number of 

 small glandular granules, which pour forth their secretion upon the 

 surface. A considerable number of them are situated within the 

 lips, in the palate, and in the floor of the mouth. They are named 

 from the position which they may chance to occupy, labial, pala- 

 tine glands, &c.J 



* Thomas Wharton, an English physician, devoted considerable attention to the ana- 

 tomy of the various glands : his work, entitled " Adenographia," &c., was published in 

 1656. 



t Nicholas Stenon, a Danish anatomist ; he was made professor in Copenhagen in 

 1672. 



\ These glands are salivary, having the same structure as the parotid and secreting 

 the same fluid. G. 



