THE NASAL FOSSAE, PHARYNX, AND TONSILS. 373 



ing located in the deeper layers of the connective tissue. In 

 man their shape varies somewhat from that of simple tubules, 

 as several glandular tubes ordinarily unite in a common excre- 

 tory duct, so that, in some cases, the gland almost appears 

 racemose. The glandular cells are partly round, partly irreg- 

 ular in shape, and have many pale nuclei, together with a 

 brownish-colored pigment. 



THE PHARYNX. 



The mucous membrane of the pharynx is, in general, simi- 

 lar to that of the mouth. It consists essentially of a stratified 

 pavement-epithelium, a rather loosely woven submucosa, which 

 contains aggregations of mucous glandules, and a tunica pro- 

 pria composed of fibrillary connective tissue and furnished 

 with papillae. The papillae are smaller than those found lower 

 down in the oesophagus. The mucous glandules are most 

 abundant in the superior part of the pharynx. The mucous 

 membrane of the vault of the pharynx, and in the vicinity of 

 the isthmus of the fauces, where it becomes continuous with the 

 mucous membrane of the nasal cavity, to some extent assumes 

 the characteristics of the latter. In this region the connective 

 tissue is more or less thickly interspersed with lymphoid cells. 

 It is provided, moreover, with ciliated cylindrical epithelium. 

 In adults this epithelium extends some distance backward until 

 it passes into the stratified pavement variety. In children, 

 however, ciliated epithelium lines the whole naso-pharynx. 

 In the upper and lateral parts of the pharynx are found cer- 

 tain aggregations of adenoid tissue, most abundantly in the 

 vault of the pharynx, extending from one Eustachian tube to 

 the other. This tissue is generally quite diffuse, but is identi- 

 cal in its structure with the lingual follicular glands arid with 

 the tonsils, and from this resemblance it has derived the name 

 "pharyngeal tonsil." 



THE TONSILS. 



The tonsil consists essentially of a reduplication, more or 

 less extensive, of the oral mucous membrane, containing in its 

 folds an abundance of the so-called adenoid tissue. 



