PHARYNX. 177 



we may distinguish serous, mucous, and mixed glands. They 

 possess neither intercalary nor intralobular ducts. The ducts 

 often are covered at their mouths with ciliated epithelium. 



Serous glands are found only in the tongue, in the region of 

 the circumvallate papillae. These are called v. Ebner's glands. 

 The ducts open in the furrows surrounding the circumvallate 

 papillae. In these glands also secretory capillaries may be 

 present. 



Small mixed glands have the structures described for the 

 sublingual gland. Secretory capillaries are plainly to be made 

 out. To these belong the labial and buccal glands, and those 

 glands at the under side of the tip of the tongue, described by 

 Blandin and Nuhn. 



The palatine glands and the glands at the root of the 

 tongue are purely mucous. 



B. PHARYNX. 



The mucous membrane of the pharynx resembles that of 

 the mouth cavity. We find here also a stratified epithelium 

 and a tunica propria with papillae. The stratified epithelium 

 of the nasopharynx is converted in the region of the nasal cavi- 

 ties into a many-layered ciliated epithelium, which is continu- 

 ous above with the ciliated cylindrical epithelium of the nasal 

 mucous membrane. 



The tunica propria of the pharynx is supplied richly with 

 adenoid tissue, which in places is collected to form the pharyn- 

 geal tonsils. Under the tunica propria there is a layer of elastic 

 fibres running longitudinally, the elastic limiting layer, which 

 is continued down to the oesophagus, where it gradually disap- 

 pears. It lies, for the most part, on the inner surface of the 

 pharyngeal muscles, and sends strong bands of elastic fibres 

 into the interrnuscular septa (J. Schaffer). In these places 

 the submucosa is wanting, and the mucous glands extend 

 down and branch between the muscle bundles. In the laryn- 

 geal part the elastic limiting layer is separated from the mus- 

 cle, and here there is a distinct submucosa, in which the 

 glands lie. 



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