CORNEA. LENS. RETINA. 103 



edge of the internal elastic lamina, and its fibres cross the 

 angle of junction and penetrate into the iris. The ciliary 

 portion of the choroid is pervaded by branching pigment cells; 

 its inner surface is covered by a deeply pigmented layer, upon 

 which rest clear columnar cells ; these are continued to the 

 retina. This inner layer is much folded and a thin homo- 

 geneous membrane is attached to its surface (suspensory 

 ligament to choroid and inner limiting layer). The strands of 

 the ciliary muscle (plain) will be observed radiating outwards 

 from the corneo-sclerotic junction into the ciliary body. The 

 union of the choroid and retina occurs further back ; observe 

 the angular bend of the surface at the ora serrata. 



Cornea. Cat. Y. & L.S. (s. Ran vier's gold method, c. P., m. B.) 

 (H) Examine these successively for the distribution of nerves, 

 the superficial plexus of which is best seen and lies immediately 

 beneath the conjunctival epithelium. In the L.S., besides an 

 irregularly distributed plexus of nerves, observe the branching 

 processes of the corneal corpuscles. 



Lens fibres. Cod's eye. (Boiled in water, teased in the same, 

 stained s. 19, m. F.) The band-like fibres seen on edge in clusters 

 exhibit ridges. Seen isolated in side view they are smooth, with 

 denticulated margins (whereby they interlock). 



Optic papilla. Bog. Y.S. (p. 11, 22 & 24, c. P., m. B.) 3Q 

 Find the entrance of the optic nerve through the sclerotic 

 (cribriform lamina) and its overflow laterally over the choroid, 

 and the appearance of the retina immediately outside. A 

 central section will show the central artery of the retina cut 

 lengthways. 



Retina of Cat, for general structure, (p. 8, s. 22 & 24, c. P., 

 m. B.) The inner layer, i.e., that which lies nearest the vitreous 

 humour, is smooth and bounded by the inner limiting membrane, 



