MEIBOMIAN GLANDS CARUNCULA LACHRYMALIS. 35 7 



over the cornea with difficulty, so much so that its exist- 

 ence here is deniecf by some. From the lids it is continu- 

 ous with the skin in one direction, and in another lining 

 the Meibomian follicles, excretory ducts of the lachrymal 

 gland, and puncta lachrymalia. At the inner canthus of 

 the eye it forms a semi-lunar fold, called plica semilunaris, 

 which represents the membrana nictitans of quadrupeds, 

 or the third eyelid of birds. This fold has a thin fibro- 

 cartilaginous plate, and is very vascular. 



Caruncula lachry mails. This is a small projection of a 

 bright red color in health, but pale and flaccid in disease, 

 situated at the inner canthus, between the lachrymal ducts 

 and within the lacus lachrymalis. Its structure consists of 

 an assemblage of minute follicles surrounded by a dense 

 fibro-cartilaginous tissue; it furnishes the whitish secre- 

 tion so often seen at the inner canthus. 



Meibomian glands, (Fig. 103.) These are situated on the 

 posterior surface of the lids, covered by the tunica conjunc- 

 tiva, and imbedded in grooves of FIG. 103. 

 the tarsal cartilages. They are 

 seen as strings of long parallel 

 ducts, of a pale yellow about 

 thirty in number to the upper 

 lid, and not quite so many to the 

 lower, opening on the margin of 

 each lid, by a row of minute ori- 

 fices, behind the cilia. These are 

 visible with a lens. Each Meibomian gland is simply 

 an inflection of the mucous membrane, forming a follicle 

 which is extended into a long and tortuous tube, having 

 a coacal termination surrounded by numerous small and 

 clustered follicles which open into it, and constitute so 

 many offsets, or ccecal diverticula. 



Function. To secrete an unctuous fluid which lubricates 

 the margins of the lids, and prevents their adhesion, which 



FIG. 103 represents the Meibomian glands. 1 Meibomian glands as seen 

 on the inner side of the lids. 2 Entrance to puncta lachrymalis. 3 Carun- 

 cula lachrymalis. 



