364 MICROSCOPIC ANATOMY OF THE 



(2) The Lachrymal Apparatus. 



The lachrymal gland is a compound tubular gland which, 

 from the nature of its secretion, must be regarded as serous. 

 The ducts, which are numerous, are clothed with cylindrical 

 epithelium, and receive the secretion directly from the inter- 

 mediate portion of the gland. This intermediate portion, or 

 neck, is lined with lower epithelium, and is continuous with 

 the end portion or body of the gland. The latter is made up 

 of granular serous cells surrounded by a membrana propria. 

 In this there are stellate basket cells, which form a network 

 around the gland tubules. The interstitial connective tissue 

 contains a great many elastic fibres. 



The walls of the lachrymal canals consist of stratified pave- 

 ment epithelium and a richly vascular connective-tissue layer, 

 which contains numerous elastic fibres. The walls lie on the 

 longitudinal cross-striated muscle bands of the orbicularis 

 muscle. 



The tear sac and nasal duct are clothed with a double layer 

 of cylindrical epithelium which may contain goblet cells. The 

 tunica propria contains many leucocytes. 



The nerves of the lachrymal glands are almost entirely non- 

 medullated. They form a network in the membrana propria 

 of the tubules, and from this fine fibres run through the mem- 

 brana propria. These form a plexus at the bases of the cells, 

 and a second one between the gland cells. These come into 

 immediate contact with the gland cells. 



3. AUDITORY ORGAN. 



In the auditory organ we distinguish three parts : the inner 

 ear, the middle ear, and the outer ear. 



(a) The Inner Ear. 



The inner ear is the most essential part of the auditory 

 organ, for it contains the end apparatus of the auditory nerve. 

 It is an organ of extremely complicated structure, and is known 

 as the labyrinth. In it two main sacs are to be noted, the sac- 

 culus and the utriculus, which are joined by a narrow canal, 



