THE PROTECTIVE ORGANS OF THE EYE. 



471 



3. Besides the tarsus (fibrocartilage) the middle layer of the eye- 

 lid contains : (i) The musculus orbicularis oculi, which lies beneath 



Tfc. 



Fig. 364. Vertical section of the upper eyelid of man; X H : a /> arterial arcus tar- 

 seus ; c, cilia; dgt, excretory duct of Meibomian gland ; glc, ciliary gland (Moll) ; McA', 

 ciliary muscle of Riolani; Mop, m. orbicularis palpebrarum; Alt, nonstriated muscle-fibers 

 of the tarsal muscle and tendon of the levator palpebrie superioris ; nlc, lymph-node of 

 the conjunctiva palpebroe ; 7] tarsus (Sobotta, "Atlas and Epitome of Histology."). 



the subcutaneous tissue. At the margin of the lid this structure 

 gives off the musculus ciliaris Riolani, which is composed of two 



