376 MHTjwurH- .[.\ATOMY or nil-: 



lymph follicles, which taken together arc called tultnl /o//,s/7x. 

 The cartilage of the tube presents the structure of fibrous 

 cartilage in the pharyngeal section. Sometimes elastic tissue 

 also is present in this cartilage. In the upper parts of the 

 tube the cartilage is hyaline. 



(e) The Outer Ear. 



The tympanic membrane (drum) forms the boundary be- 

 tween the middle and the outer ear. It is made up of three 

 layers: the innermost or a continuation of the mucous mem- 

 brane of the tympanic cavity ; the outermost, on the contrary. 

 is connected with the covering of the external meatus. From 

 within outward the layers are : 



(1) The mucous layer (stratum mucosum) ; 



(2) The fibrous layer (lamina propria) : and 



(3) The cutaneous layer (stratum cutaneum). 



(1) The stratum mucosum consists of a single layer of flat. 

 epithelial cells and a thin connective-tissue sheath which is 

 intimately connected with the fibrous layer. 



(2) The lamina propria is made up of two layers of 

 connective-tissue fibres, the inner circular and the outer 

 radial. The two layers are bound together by a little loose 

 connective tissue. 



(3) The stratum cutaneum consists of stratified epithelium 

 and a thin connective- tissue corium in which no papillae are 

 present. The epithelium is made up of a Malpighian layer 

 of one or two rows of cells and many layers of corneous non- 

 nucleated epithelial cells. 



The skin of the external meatus has a different structure in 

 its various parts. The subcutaneous tissue is firm and the corium 

 shows only very poorly developed papilla?. Numerous hairs 

 and sebaceous glands occur here. Large coil glands (glanduhe 

 ceruminosse), whose structure resembles that of large sweat 

 glands, are also found. Two parts can be recognized in these 

 glands: the secreting body of the gland and the duct, The 

 first consists of a layer of cubical gland cells, a layer of smooth 

 muscle cells, and a homogeneous rnembrana propria. The 



