THE EYE. 



435 



pebral portion adheres intimately to the tarsal plate 

 and presents numerous papillae. It is covered by a 

 layer of columnar cells beneath the bases of which 

 are small flattened cells. Goblet cells are to be found 

 among these cells. Over the globe of the eye it ad- 

 heres closely to the sclera, and this portion of the 

 conjunctiva is perfectly smooth and is composed of 

 stratified squamous epithelium. The conjunctiva 

 that clothes the eyelid is thinner than that which 

 covers the cornea and any for- 

 eign particle, therefore, tends 

 to cling to the eyelid rather 

 than to the eye. 



The Lacrimal Apparatus. 

 This consists of (i) the lacri- 

 mal or tear gland, (2) the lac- 

 rimal canals, and (3) lacrimal 

 sac, or nasal duct. 



The lacrimal gland is a 

 branched tubular gland situ- 

 ated in the upper and outer 

 part of the orbital cavity. Its 

 structure resembles that of a 



serous gland. The ducts, which are numerous, are 

 clothed with stratified epithelium and open on the 

 conjunctival surface, over which the secretion is 

 evenly distributed by the action of the eyelids. 



The lacrimal canals begin as two minute orifices 

 at the apices of the papillae lacrimales situated near 

 the inner canthus. They are lined by stratified 

 epithelium and open directly into the lacrimal sac. 

 The latter is lined with simple pseudostratified epi- 



Fig. 300. i, Canalicu- 

 lus; 2, lacrimal sac; 3, na- 

 sal duct; 4, plica semilu- 

 naris; 5, caruncula lacri 

 malis (Leidy). 



