92 THE EYE AND EAR. 
iv. The choroid: the black pigmented layer lining 
the sclerotic, and continuous in front with the 
iris. 
v. The retina; a delicate transparent membrane 
lining the posterior two-thirds of the eye: it is 
readily detached from the choroid, except at 
the entrance of the optic nerve with which it is 
continuous, 
B, The Eye of the Sheep or Ox. 
Fig. 14. A diagrammatic section through the eye of a mammal passing 
through the centres of the cornea and lens, and through the yellow spot and 
point of entrance of the optic nerve. 
A, anterior chamber: Ar, central artery of retina: B, blind spot: 6, 
cornea : Ch, choroid: CP, ciliary processes: H, hyaloid membrane, enclosing 
the vitreous humour: |, iris: L, lens: O, opticnerve: P, posterior chamber : 
R, retina: S, sclerotic: SL, suspensory ligament: Y, yellow spot. 
