514 ANATOMICAL TECHNOLOOT. 



OCULUS— THE ETE AND ITS APPENDAGES. 



General References.— Gray, A, 713 ; Quain, A, 11, 583 ; Dalton, A, 519 ; Foster and 

 Langley, A, 178, 244 ; Hyrtl, A, 391 ; Leyh, A, 328 ; Straus-Dnrckheim, A, 201 ; Strieker, 

 A, 802 ; Morrell, A, 260 ; Chauveau, A, 862 ; Chanveau (Fleming), A, 817 ; Owen, A, III, 

 246 ; Foster, A, 510 ; Gurlt, A, 775 ; Milne-Edwards, A, XII, 94 ; Bernstein, A, 48 ; Flint, 

 A ; Le Conte, A. 



Instruments and Material. — Scalpel ; arthrotome ; fine and coarse scissors ; fine and 

 coarse forceps ; tracer ; flexible blow-pipe ; nippers ; tripod lens ; beaded bristles ; skull 

 prepared as in Fig. 56. 



§ 1399. The eye is the organ of the sense of sight (§ 1394, D). 

 It is situated in the orbital fossa (Fig. 56), which in the cat is in- 

 complete. 



In connection with the eye proper are certain appendages which 

 protect, lubricate and move the eyeball. 



APPENDAGES OF THE ETE. 



§ 1400. Palpebrse, eyelids. — The eyelids are modified folds of 

 skin which protect the cephalic surface of the eye. There are two 

 for each eye, which from their position are called respectively the 

 dorsal (upper) and ventral (lower) lid. Their ectal surface is cov- 

 ered with hair, but there. are no eyelashes ; their ental surface, that 

 next the eyeball, is lined with a smooth mucous membrane, the 

 conjunctiva (Fig. 126, cnjct.). 



The two points where the eyelids meet are called the canthi or 

 angles of the lids ; a mesal (inner) or nasal and a lateral (outer) or 

 temporal canthus. 



Dissection of the Lids. — Make an incision through the skin 

 from the angle of the mouth to a point opposite the base of the ear, 

 and th'jn transversely to the dorsimeson. Then make an incision 

 from the lateral canthus directly caudad to the transverse incision. 

 Reflect the ventral eyelid and the skin nearly to the mesal canthus, 

 noting that the smooth mucous membrane (conjunctiva) lining the 

 lid is continuous with the covering of the eyeball (Fig. 126). 



§ 1401. Meibomian G-lands. — Grasp the free edges of the lids 

 and evert them. On the mucous membrane there will be seen 

 many parallel, broad, yellowish lines, extending from the edge of 

 the eyelid for about 2 mm. (Fig. 126). These are the Meibomian 

 glands. They secrete a sebaceous substance which is poured out 

 upon the edges of the lids through minute orifices ; these may be 

 seen at the top of slight elevations by employing a tripod magnifier. 



