THE ORGANS OF SPECIAL SENSE 



55"; 



of 



(i) The lamina suprachorioidea. 



(2) The layer of straight vessels — Mailer's layer. 



(3) The capillary layer — choriocapillaris. 



(4) The vitreous membrane — lamina citrea — membrane 



Brach. 

 (i) The lamina suprachorioidea (Fig. 367, d) is intimately con- 

 nected with the lamina fusca of the sclera and consists of loosely 

 arranged bundles of fibrous and elastic tissue among which are scat- 

 tered pigmented and non-pigmented 

 connective-tissue cells. Numerous 

 lymph spaces are found between the 

 bundles of connective tissue and be- 

 tween the lamina suprachorioidea and 

 lamina fusca. The latter are known 

 as the pericliorioidal lymph spaces 

 (Fig. 371). 



(2) The layer of straight vessels (Fig. 

 367, e) consists of fibro-elastic tissue 

 containing numerous pigmented and 

 non-pigmented cells, supporting the 

 large blood-vessels of the layer. The 

 latter can be seen with the naked eye, 

 and, as they are straight and parallel, 

 give to the layer a striated appearance. 

 The arteries lie to the inner side. The 

 veins — vence vorticosce — are larger than 

 the arteries and converge toward four 

 points one in each quadrant of the 

 eyeball. 



A narrow boundary zone, rich in 

 elastic fibres and free from pigment, 



limits this layer internally. It is much more highly developed in 

 some of the lower animals than in man. Formed of connective- 

 tissue bundles in ruminants and horses, it is known as the tapetum 

 fibrosum, while in the carnivora its structure — several layers of flat 

 cells — gives it the name of the tapetum cellulosum. 



(3) The choriocapillaris (Fig. 367,/) consists of connective tissue 

 supporting a dense network of capillaries, which is most dense in the 

 region of the macula lutea. This layer is usually described as free from 

 pigment, although it not infrequently contains some pigmented cells. 



Fig. 368. — Vertical Section of 

 Cornea. (Merkel-Henle.) i, An- 

 terior epithelium; 2, anterior elastic 

 membrane; 3, substantia propria 

 corneae; 4, posterior elastic mem- 

 brane; 5, posterior endothelium. 



