2 9 2 ELEMENTS OF tfisroLOGV. fchap. xxxv 



which is not cartilage, but very dense, white, fibrous 

 tissue. In it lie embedded the Meibomian glands. 

 These extend in each eyelid in a vertical direction 

 from the distal margin of the tarsal-plate to the free 

 margin of the eyelid ; in the posterior angle of this 

 margin lies the opening or mouth of each of the 

 Meibomian glands. 



The duct of a Meibomian gland is lined with a 

 continuation of the stratified pavement epithelium, 

 lining the free margin of the lid ; it passes in the 

 tarsal-plate toward its distal margin, and takes up on 

 all sides short minute ducts, each of which becomes 

 enlarged into a spherical, saccular, or flask-shaped 

 alveolus. This is identical in structure and secretion 

 with the alveoli of the sebaceous follicles of the 

 skin. 



400. The conjunctival layer is separated from the 

 subcutaneous tissue of the skin-layer of the eyelid by 

 the bundles of the sphincter orbicularis striped mus- 

 cular tissue. Some bundles of this extend near the 

 free margin of the lid, and represent what is known 

 as the musculus ciliaris Riolani. This sends bundles 

 around the mouth of the Meibomian ducts. 



401. At the anterior angle of the free margin of 

 the lid are the eyelashes or cilia, remarkable for their 

 thickness and rapid reproduction. Near the cilia, but 

 towards the Meibomian ducts, open the ducts of pecu- 

 liar large glands the glands of Mohl. Each of these 

 is a wavy or spiral tube, passing in a vertical direction 

 from the margin of the lid towards its distal part ; it 

 completely coincides in structure to the large portion 

 of a sweat gland i.e., that part containing a columnar 

 epithelial lining, and between this and the membrana 

 propria a longitudinal layer of non-striped muscular 

 cells. 



The free margin is covered, as mentioned above, 

 with stratified pavement epithelium, into which the 



