462 ORGAN OP TASTK. 



other, and forming interlacements and loops, and they terminate 

 upon the inner surface of the membrane in minute papillae, resem- 

 bling those of the retina. 



The Cochlear nerve divides into numerous filaments which enter 

 the foramina of the tractus spiralis foraminulentus in the base of the 

 cochlea, and passing upwards in the canals of the modiolus bend 

 outwards at right angles, to be distributed in the tissue of the lamina 

 spiralis. The central portion of the nerve passes through the tubulus 

 centralis of the modiolus, and supplies the apicial portion of the 

 lamina spiralis. In the lamina spiralis the nervous filaments lying 

 side by side on a smooth plane form numerous anastomosing loops, 

 and spread out ultimately into a nervous membrane. According to 

 Treviranus and Gottsche the ultimate terminations of the filaments 

 assume the form of papillae. 



The Arteries of the labyrinth are derived principally from the 

 auditory branch of the superior cerebellar artery. 



ORGAN OF TASTE. 



The Tongue is composed of muscular fibres, which are distributed 

 in layers arranged in various directions : thus, some are disposed 

 longitudinally; others transversely; others, again, obliquely and 

 vertically. Between the muscular fibres is a considerable quantity 

 of adipose substance. 



The tongue is connected posteriorly with the os hyoides by mus- 

 cular attachment, and to the epiglottis by mucous membrane, form- 

 ing the three folds which are called frcena epiglottidis. On either 

 side it is held in connexion with the lower jaw by mucous mem- 

 brane, and in front a fold of that membrane is formed beneath its 

 under surface, which is named franum lingua. 



The surface of the tongue is covered by a dense layer analogous 

 to the corium of the skin, which gives support to the papillae. A 

 raplie marks the middle line of the organ, and divides it into sym- 

 metrical halves. 



The PapillcB of the tongue are the 



Papillae circumvallatae, 

 Papillae conicas, 

 Papillae filiformes, 

 Papillae fungiformes. 



The Papilla circumvallatce are of large size, and from fifteen to 

 twenty in number.* They are situated on the dorsum of the tongue, 

 near to its root, and form a row upon each side, which meets its 

 fellow at the middle line, like the two branches of the letter V. 

 Each papilla? resembles a cone, attached by its apex to the bottom 

 of a cup-shaped depression: hence they are also named papilla? 



* * I think it rare to see more than nine, four on each side of the middle one, which 

 is always the largest. G. 



