THE EAR 



columnar ciliated \arielv, continuous with, and similar to the respiratory 

 epithelium of the nasopharynx, together with a fibrous membrana 

 propria which is loosely connected with the surrounding bony, car- 

 tilaginous, and muscular walls. The lower portions of the tube are 

 richly supplied with mucus-secreting, tubulo-acinar glands, and toward 



FIG. 577. TRANSECT: ON OF THE EUSTACHIAN TUBE; DIAGRAMMATIC. 



1, cartilaginous plate; 2, median or hooked end of the cartilage; 3, 'dilator tubse' 

 (tensor palati); 4, levator palati; 5, fibrocartilage at the base of the skull; 6 and 7, 

 mucous glands; 8, adipose tissue; 9, 11, lumen of the tube; 10, 12, connective tissue. 

 Low magnification. (After Rudinger.) 



its pharyngeal end the mucosa is much infiltrated with lymphoid tissue, 

 thus forming the lubal tonsil of Gerlach. 



The carl ilage of the auditory tube is firmly adherent to the bony wall. 

 At the point of attachment it has a hyaline structure, the fibers of 

 Hie perichondrium penetrating only the surface of the cartilaginous 

 plate. Lower down the cartilage becomes infiltrated with fibers and 

 conforms to the typical elastic variety. Like the cartilage of the auricle 

 it is rich in cellular elements. Its trausection presents a peculiar hook- 

 like form, by means of which the posterior surface, the superior margin, 

 and the upper portion of the anterior surface are invested by cartilage, 



