264 



THE ESSENTIALS OF HISTOLOGY. 



animals, but in the human eye it is dark brown. It is composed of 

 connective tissue, the cells of which are large and filled with pigment 

 (figs. 291, 292), and it contains in its inner part a close network of 

 blood-vessels, and in its anterior part the involuntary muscular fibres 



FIG. 294. SECTION (FROM THE EYE OF A MAN, AGED 30), SHOWING THE 

 RELATIONS OF THE CORNEA, SCLEROTIC, AND IRIS, TOGETHER WITH THE 



CILIARY MUSCLE, AND THE CAVERNOUS SPACES NEAR THE ANGLE OF THE 



ANTERIOR CHAMBER. (Waldeyer. ) (Magnified.) 



A, epithelium ; B, conjunctival mucous membrane ; C, sclerotic ; D, membrana supracho- 

 roidea ; E, opposite the ciliary muscle ; F, choroid, with ciliary processes ; G, tapetum 

 nigrum and pars ciliaris retinae ; //, cornea (substantia propria) ; /, iris ; K, radiating 

 and meridional, and L, circular or annular bundles of the ciliary muscle ; M, bundles 

 passing to the sclerotic ; N, ligamentum pectinatum iridis at the angle, 0, of the an- 

 terior chamber ; P, line of attachment of the iris. 1, anterior homogeneous lamina of 

 the cornea ; 2, posterior homogeneous lamina, covered with endothelial cells which are 

 continued over the front of the iris ; 3, cavernous spaces at the angle of the anterior 

 chamber (spaces of Fontana) ; 4, canal of Schlemm, with endothelial lining, and with a 

 vessel, 5, leading from it ; 6, other vessels ; 7, bundles of fibres of the sclerotic having 

 a circular direction, cut across ; 8, larger ones in the substance of the sclerotic ; 0, fine 

 bundles cut across, at limit of cornea ; 10, point of origin of meridional bundles of 

 ciliary muscle ; 11, blood-vessels in sclerotic and conjunctiva, cut across ; 12, section 

 of one of the ciliary arteries. 



of the ciliary muscle, which pass backwards from their origin at the 

 junction of the cornea and sclerotic, to be inserted into the choroid. 

 The choroid is separable into the following layers, enumerated from 

 without in : 



