Chap. XXXVIL] THE ClLIARY PROCESS. 303 



non-medullated fibres for the anterior surface ; and 

 (c) a network of non-medullated fibres for the 

 sphincter pupillse. 



The capillary blood-vessels are also accompanied 

 by fine nerve-fibres (A. Meyer), and, according to 

 Fa her, there exist ganglion cells in these nerve net- 

 works. 



424. II. The ciliary processes are similar in 

 structure to the iris, except, of course, that they do 

 not possess an anterior endothelium or an anterior 

 basement membrane. The substantia propria is 

 fibrous tissue with elastic fibres and numerous 

 branched cells, pigmented in dark (but not in blue) 

 eyes. The posterior basement membrane is very 

 thick, and is called the lamina vitrea ; in it may be 

 detected bundles of fine fibrils. It possesses perma- 

 nent folds arranged in a network (H. Miiller). The 

 inside of it is covered with a layer of pigmented poly- 

 hedral epithelium, the tapetum nigrum : the cells are 

 polygonal when viewed from the surface. The in- 

 dividual cells are separated by thin lines of a trans- 

 parent cement substance. This pigmented epithelium 

 is covered with a layer of transparent columnar 

 epitheloid cells, each with an oval nucleus. These are 

 closely fixed on the tapetum nigrum, and represent a 

 continuation of the retina over the ciliary processes : 

 this is the pars ciliaris retinae, (Fig. 154). 



425. The arterial branches for the ciliary processes 

 and muscle are chiefly derived from the circulus arte- 

 riosus iridis major, and form a dense network of 

 capillaries for the former; to each of these corre- 

 sponds a conical group of capillaries (Fig. 153). 



426. III. The choroid membrane consists 

 counting from outwards, i.e.. from the sclerotic, inwards, 

 i.e., towards the retina of the following layers : 



(1) The membrana supra-choroidea. This is a 

 continuation of the sclerotic, with which it is identical 



