

STEOMA OF THE CHOROID. 309 



The fibres of this plexus, anastomosing with each other, run 

 for the most part in a direction parallel to the surface of the 

 sclerotic, giving off at the same time but few processes into the 

 adjoining layers; it thus appears as if the fibres were inter- 

 woven into several distinct membranes, of which one, the 

 lamina fusca of authors, usually adheres to the sclerotic, and 

 the other thicker one to the choroid. The latter again splits 

 into several superimposed laminae, which, commencing at the 

 posterior part of the ciliary body, extend to the entrance of the 

 optic nerve (membrana suprachoroidea). 



The fibrillar stroma which occupies the interspaces between 

 the vessels is in immediate relation with this membrana 

 suprachoroidea. 



The stroma of the choroid contains numerous cells ; the most 

 characteristic of these are the stellate pigment cells, which 

 differ somewhat in their form in the superficial and deep layers 

 of the membrane. The cells in the superficial layers are 

 stellate, with short, broad, and flat surfaces ; their dark-brown 

 pigment is absent in the immediate vicinity of the nucleus, 

 which is consequently always sharply defined. The deep-lying 

 stellate cells, which completely fill the interspaces between 

 the vessels, are thicker than they are broad, and are pro- 

 vided with long thin processes, which frequently anastomose 

 and form a close plexus with the processes of the adjoining 

 cells. These cells are usually of darker colour than the super- 

 ficial ones. 



Besides pigmented cells, we also meet with the most diverse 

 forms of non-pigmented cells in the choroid. Amongst these 

 the spheroidal cells deserve special notice, which in size and 

 form closely resemble the white blood or the lymph corpuscles.* 

 These are met with in all the layers of the choroid, but chiefly 

 in the deepest layers between the capillaries. Like the white 

 blood corpuscles, they can change their form, and move from 

 place to place. They vary considerably in number, according 

 to age and the healthy state or otherwise of the eye. They 

 are very numerous in children, but are met with in dispropor- 

 tionately small number in adults, in whom, however, their 



* Hasse, Archiv fur Ophthalmologie, Band iv., p. 57. 



