THE EYE AND ITS APPENDAGES 99 



consists of an internal layer of hyaline cartilage 

 with a superposed layer of fibrous tissue. 

 Close to its junction with the cornea the sclera 

 contains a bony scleral ring. 



Within the sclera is a vascular and pigmented 

 tunic divisible into choroid, ciliary body, and 

 iris. The choroid is a thin, dark-coloured 



*;• C.I. 



o.n. 



Fig. 50. — Section through the Eyeball. 



c, cornea ; c.l., crystalline lens ; i., iris ; s.r., scleral ring ; c.b., ciliary body ; 

 v.b., vitreous body ; s., sclera ; eh., choroid ; r., retina ; p., pecten ; o.n., optic nerve. 



membrane lining the posterior part of the 

 eyeball. The ciliary body is the thickened and 

 radially folded anterior part of the choroid. 

 Associated with it is the ciliary muscle^ com- 

 posed of striated fibres, upon which depends 

 the rapidly effected accommodation of the 

 eye for near or distant objects. A remarkable 

 structure, known as the pecten, projects into 



