APPENDAGES OF THE EYE 677 



corium. Its epithelium comprises four or five layers of cells, the deeper 

 of which are small and spheroidal, and the superficial elongated oT crmi- 

 cal, their blunt ~ ends forming the free surface of the conjunctiva, their 

 pointed extremities buried between the cells of the deeper layers. The 

 bases of these elongated cells become somewhat expanded and broader 

 from the increased tension of the conjunctiva when the lids are closed; 

 they retract and become narrower when the lids are separated and the 

 conjunctiva relaxed. 



The cells of the superficial layer are often so distinctly elongated 

 as to possess a columnar form. They may, however, be spheroidal or 

 even somewhat flattened, in which case they very closely resemble the 

 ordinary type of stratified squamous epithelium. The epithelial layer 

 rests almost directly upon the connective tissue corium, the basement 

 membrane being imperfectly developed. 



The corium of the conjunctiva is thin. With the aid of a thin layer 

 of submucous areolar tissue it unites the epithelium to the tarsus and 

 to the fibers of the orbicularis muscle; near the margin of the lid its 

 submucous tissue incloses the Meibomian glands. Opposite the plane 

 at which the blind ends of the Meibomian glands are embedded in the 

 free margin of the tarsus, the conjunctival surface is thrown into eight 

 to twelve horizontal folds, beneath which, in the connective tissue, are 

 a few minute tubulo-alveolar glands, the posterior tarsal glands (glands 

 of Waldeyer; glands of Henle). Their ducts open upon the free surface 

 of the conjunctiva near the fornix conjunctivse. 



At the attached base of the lid a narrow band of smooth muscle Ex- 

 tends from the levator palpebraa and inferior oblique muscles into the 

 body of the lid. These fibers have been described by H. Miiller (1858) 

 as the superior and inferior palpebral muscle of the upper and lower 

 lid, respectively, and have come to be known as the muscle of Miiller. 



The fold by which the palpebral conjunctiva is reflected upon the 

 globe of the eye to become continuous with the ocular portion of the 

 membrane is known as the fornix conjunctive. The extremely loose 

 attachment of the conjunctiva of the fornix to the underlying connective 

 tissue and intra-orbital fat permits the great freedom of motion which 

 is characteristic of the ocular globe. The small accessory lacrimal glands 

 (glands of Krause) open into the margin of the fornix conjunctivas. 

 The superior fornix contains from eight to twenty, the inferior from 

 two to five. In this region, also, occasional goblet cells occur in the 

 superficial layers of the epithelium. 



The ocular conjunctiva is likewise very loosely attached to the sclera. 



