Mr. Young's Observations on Vision . 
181 
Explanation of the Figures. 
Tab.XX. fig. 1. A vertical section of the ox's eye, of twice 
the natural size. 
A. The cornea, covered by the tunica conjunctiva. 
BCB. The sclerotica, covered at BB by the tunica albugi- 
nea, and tunica conjunctiva. 
DD. The choroid, consisting of two laminas. 
EE. The circle of adherence of the choroid and sclerotica. 
FG, FG. The orbiculus ciliaris. 
HI, HK. The uvea : its anterior surface the iris ; its pos- 
terior surface lined with pigmentum nigrum. 
IK. The pupil. 
HL, HL. The ciliary processes, covered with pigmentum 
nigrum. 
MM. The retina. 
N. The aqueous humour. 
O. The crystalline lens. 
P. The vitreous humour. 
QR, QR. The zona ciliaris. 
RS, RS. The annulus mucosus. 
Fig. 2. The structure of the crystalline lens, as viewed in 
front. 
Fig. 3. A side view of the crystalline. 
2 B 
MDCCXCIII. 
