THE EYE 



1525 



Structure of the Ora Serrata.— At the ora serrata, as previously 

 stated, the nervous elements of the retina terminate, and its pig- 

 mentary layer is continued over the deep or posterior surfaces of 

 the ciliary processes. In this latter situation there is superadded 

 to its deep or posterior surface a layer of columnar epithelial cells, 

 and the two layers form the pars ciliaris retinae, which is continued 



Fig. 638. — Scheme of the Retina, showing the Connection between 

 THE Layer of Rods and Cones and the Ganglionic Layer 

 (Ramon y Cajal). 



A. Layer of Rods and Cones 



B. Outer Nuclear Layer 



C. Outer Molecular Layer 



E. Inner Nuclear Layer 



F. Inner Molecular Layer 



G. Ganglionic Layer 



H. Layer of Nerve-fibres 

 M. Mailer's Fibre 



a. Rods 



b. Cones 



c. Granule of Cones 



d. Granule of Rods 





Bipolar Cells of Rods 

 f. Bipolar Cells of Cones 

 - r Ganglionic Corpuscles ramifymg at 

 S.'°'''J different levels in Inner Molecular 

 Layer 

 Deep arborizations of Bipolar Cells 

 s. Centrifugal Ner\-e-fibre 

 t. Nnclens of MuUer's Fibre 

 X. Deep ends of Rod-fibres amongst 

 superficial arborizations of Bipolar 

 Cells 

 Z. Meeting of arborizations of Omks and 

 Bipolar Cells 



into the pars iridica retinae (uvea). In the latter the cells of both 

 layers are pigmented. 



Blood-supply of the Retina. — ^The retina is supplied with blood by 

 the arteria centralis retinae, which is a branch of the ophthalmic 

 artery. Within the orbit the artery pierces the vmder aspect of the 

 optic nerve a little behind the eyebzill, and passes forwards in the 

 centre of the nerve. It makes its appearance at the centre of the 

 optic disc, £ind then divides into t^^'o branches, upper and lower. 



