78 DR KNOX on the Comparative Anatomy of the Eye. 



FIG. 3. 



A section of the Eye of the Heron. 



a The internal Ciliary Processes surrounding the margin of the Lens, 

 a a The Lens covered by its capsule. 

 b A portion of the Vitreous Humour and its capsule, 

 c The Marsupium ; p, the very delicate and sometimes transparent portion by 



which it is united to the choroid. 

 f The Choroid. 

 e The Sclerotic. 



i The Ciliary Plicae, (their internal surface). 

 g One of the sheaths, transmitted by the choroid through the sclerotic, inclosing 



blood-vessels. These sheaths are very remarkable and distinct in the eye of 



the fallow-deer, American deer, &c. 



FIG. 4. 



A section of the Eye-ball of the Cassowary, to shew the mode in which the Mar- 

 supium is formed. 



a The Marsupium. The lens has been removed. 



b A portion of the Marsupium, (where this membrane meets the choroid, and is 



continuous with it), removed, to shew the strong white medullary line of the 



Optic Nerve, 

 c The Choroid. 



d The Ciliary Body and Plicae. 

 e The posterior surface of the Iris, covered by the membrane of the Pigmentum 



nigrum. 

 / The Sclerotic. 



