3i 8 ELEMENTS OF HISTOLOGY. [Chap. XL. 



space the siipravaginal space ; and also between these 

 various sheaths are lyniph spaces the subdural or 

 subvaginal space of Schwalbe, and the subarachnoidal 

 space. The supravaginal and subvaginal spaces anas- 

 tomose with one another (Michel). 



452. Around the sclerotic is a lymph space limited 

 by a fibrous membrane the Tenonian capsule : the 

 space is called the Tenonian space. The supravaginal 

 space anastomoses with this Tenonian space, and into 

 it pass also the lymph clefts in the suprachoroidal 

 tissue (Schwalbe), by means of the lymph canalicular 

 system of the sclerotic (Waldeyer). The supracho- 

 roidal lymph spaces communicate also with the sub- 

 arachnoidal space of the optic nerve. 



CHAPTER XL. 



THE OUTER AND MIDDLE EAR. 



453. THE meatus auditorius externus is lined with 

 a delicate skin, in structure identical with, but thinner 

 than, the skin of other parts. The ceruminous 

 glands have been mentioned and described before. 

 The cartilage of the auricula and its continuation into 

 the meatus auditorius externus is elastic cartilage. 



454. The membrana tympaiii separating the 

 outer from the middle ear has for its matrix a firm 

 stratum of stiff trabeculse of fibrous connective tissue, 

 with numerous elastic fibrils and elastic membranes. 

 This is the middle and chief stratum of the membrane : 

 outwards it is covered with a delicate continuation of 

 the skin of the meatus auditorius externus, and inwards 

 with a continuation of the delicate mucous membrane 

 lining the cavum tympani. In the middle stratum of 

 the membrana tympani the trabeculse radiate more or 

 less from the junction of the manubrium mallei with 

 the membrane j bub towards the periphery many are 



