420 PRACTICAL ANATOMY. 



is in contact with the iris. Its margin is overlapped by 

 the ciliary processes. The capsule is a homogeneous 

 membrane, about $-$-$-$ i ncn thick, which, when rup- 

 tured, has a strong tendency to roll inward. It is 

 separated anteriorly from the lens proper by a single 

 layer of transparent cells, which after death absorb 

 moisture, become cloudy, forming the liquor Morgagni. 

 The lens is about one-third of an inch transversely and 

 one-quarter of an inch thick. It is an albuminoid struc- 

 ture, formed of numerous laminae, soft externally, be- 

 coming firmer, and inclosing a hard nucleus. The 

 lamina? consist of hexagonal prisms, with serrated 

 edges, accurately adjusted to each other. Each prism 

 measures about 5^7 inch in thickness. They are ar- 

 ranged to form three segments, best demonstrated by 

 immersing the lens in strong alcohol. 



The appendages of the eye are the orbital muscles, 

 described in the earlier part of the book, the eyelids 

 and eyebrows, the conjunctiva, lachrymal gland and 

 sac, and nasal duct. 



The eyelids are two thin folds placed in front of the 

 eye. The upper is the larger and more movable. When 

 the lids are separated they disclose an elliptical fissure 

 the angles of which are called the canthi. At the outer 

 canthus the lids are joined at an acute angle. The inner 

 canthus presents a triangular notch called the lacus 

 lacrymalis. At the commencement of the lacus is a 

 rounded elevation on each lid ; upon the surface of each 

 opens the punctum lacrymale. 



The eyelids are composed of skin, cellular tissue, 

 the fibres of the orbicularis palpebrarum, tarsal carti- 

 lages and ligaments, Meibomian glands, and conjuctiva. 

 The upper lid presents, also, the aponeurosis of the 

 levator palpebrae superioris. The skin is very thin, the 



