DORSO- VENTRAL SECTION OF THE EYE. 523 



is greater than its caudal. In the fresh eye it is perfectly transpar- 

 ent, and its ectal part is soft, while its ental part is firmer. In an 

 alcoholic eye it is hard and mostly opaque. 



1429. Capsula lentis (Fig. 126, Cpsl.). This is the sac surround- 

 ing the lens. Grasp the cut edges of the white zone, and attempt 

 to spread the eyeball out flat. There will be seen a tense line pass- 

 ing from the plicae ciliares to the edge of the lens. At the same 

 time look at the lens, and there will be seen enveloping it a thin 

 transparent membrane, which is the capsule. Blow with a blow- 

 pipe (Fig. 19) against the lens where the tense line is attached, and 

 the air will get between the lens and its capsule, thus making the 

 latter very evident. 



1430. Zonula Zinnii, s. Lig amentum suspensorium (Fig. 126, 

 Z. Z.). This is the fibrous connection of the lens capsule with the 

 plicse ciliares. By pulling upon the lens capsule and the sclerotic, 

 this suspensory ligament will be seen attaching itself to the Ciliary 

 pliccB (Fig. 126). 



Preparation of Fig. 126. A cat's head was removed and frozen solid. The skin was 

 cut with a scalpel along the dorsal surface of the head to indicate the direction of the sec- 

 tion. Then the section was made with a fine tooth back-saw (Fig. 21). The debris was 

 removed by carefully scraping with a scalpel, and the outlines were obtained immediately 

 by means of a photographer's camera. The relative position, size, insertion and origin of 

 the muscles were obtained by subsequent careful dissection on several specimens. The 

 form of the eyeball and the relations of the parts were verified on six eyes by carefully 

 removing and freezing them and then making sections with a watch-spring saw. 



The plica ciliares (P. c.) are about 70 in number, but in order that they might be shown 

 distinctly only a few of them were drawn. The ciliary muscle in the cat has not been sat- 

 isfactorily worked out, hence j^s limits and size have not been clearly indicated in the figure. 

 On the ventral side the retina and choroidea are shown as separated from the sclerotica 

 and from each other. Finally, the muscles of the head closely related to the M. orbicu- 

 laris palpebrarum have not been indicated. 



Description of Fig. 126. Camera aquosa posterior (C. a.). The posterior (caudal) 

 aqu^Gus chamber. It is situated between the Zonula Zinnii and the iris. 



Camera aquosa anterior (C. aq.). The anterior (cephalic) aqueous chamber. It is 

 bounded by the lens, iris and cornea. 



Canalis Schlemmii (Cn. Shim.). The canal of Schlemm in the cat is double and often 

 triple. It is a venous sinus. 



Capsula (Cpsl.). Capsule of the lens. This is an elastic sac completely inclosing the 

 lens. To it is attached the suspensory ligament or zone of Zinn. 



Choroidea, s. Tunica vasculosa. This is the dark brown membrane composed chiefly 

 of blood vessels and lying between the sclerotica and retina. It extends cephalad to the 

 iris. Opposite the zona alba of the sclerotica the choroidea is plaited or folded, forming 

 the plicae ciliares or ciliary processes. 



Conjunctiva (Cnjct.). The conjunctiva is the mucosa lining the lids, covering both 



