574 BULBUS OCULI 



boundary of the anterior chamber of the eyeball, and is 

 separated by the aqueous humour from the anterior surface 

 of the iris. 



The anterior convex surface of the cornea is clothed with 

 the conjunctiva, reduced to a transparent epithelial layer. 

 On its posterior aspect there is an elastic glassy stratum, 

 termed the posterior elastic lamina. When the cornea is 

 relaxed this membrane becomes wrinkled, and it can be 

 torn away in shreds from the proper corneal tissue. 



Ligamentum Pectinatum Iridis. At the margin of the 

 cornea the posterior elastic lamina is fibrillar, and some of 

 its fibres are continued into the iris, forming the ligamentum 

 pectinatum iridis, whilst others are prolonged posteriorly into 

 the chorioid and the sclera. The ligamentum pectinatum 

 iridis bridges across the angle between the cornea and the 

 iris, and the bundles of fibres into which the posterior elastic 

 lamina breaks up in this region constitute an annular mesh- 

 work or sponge-like series of minute spaces termed the spatia 

 anguli iridis (O.T. spaces of Fontand]. These communicate 

 with the anterior chamber of the eyeball, and are filled with 

 aqueous humour. 



Tunica Vasculosa Oculi. The intermediate or vascular 

 tunic, frequently spoken of as the uveal tract, is exposed, 

 in its entire extent, in the eyeball from which the sclera 

 and the cornea have been removed. It is separable into 

 three parts (i) a posterior portion, the chorioidea ; (2) 

 an intermediate part, the corpus ciliare ; and (3) an anterior 

 segment, the iris. 



Chorioidea. The chorioid is the largest part of the vas- 

 cular tunic. It lines the posterior segment of the eyeball, 

 between the sclera externally and the retina internally. It 

 is thickest posteriorly, where it is pierced by the optic nerve, 

 and becomes thinner anteriorly, as it approaches its union 

 with the ciliary body. Its superficial surface is connected 

 with the deep surface of the sclera by some lax connective 

 tissue, and also by blood-vessels and nerves which pass from 

 the one into the other. The deep surface of the chorioid is 

 moulded upon the retina and connected with a layer of 

 deeply-pigmented cells which usually adheres to the chorioid 

 when that tunic is removed, although in reality it is a portion 

 of the retina. 



In the eyes of many mammals, but not in man, the posterior part of the 



