CHAP. XL] 



PERIPHERAL NERVOUS END-ORGANS. 



455 



not extend so far as to afford support to those structures (the rods 

 and cones) which are eminently the end-organs of the optic nerve or 

 to those pigrnented epithelium cells which afford a close investment 

 to the outer limbs of the rods. 



Description ^ ri ^ e accom P an y m g engraving the structure of 



of the ten the retina is semi-diagrammatically represented, so as 



layers of the to shew with clearness the position, and the mutual 



relations, of the ten layers which, since Max Schultze's 



description, histologists have agreed to distinguish. 



The first layer (1, Fig. 62) is composed of the so-called membrana 

 limitans internet, which is a fibrillated membrane belonging to the con- 

 nective-tissue framework. 



The second layer (2, Fig. 62) is the nerve-fibre layer and is composed 

 of naked axis-cylinders continuous with the optic nerve fibres which 

 having pierced the sclerotic and cornea enter the retina at the ' col- 

 liculus nervi optici! 



The third layer (3, Fig. 62) the nerve-cell or ganglionic layer, is com- 



FlO. 62. DIAGRAMMATIC SECTION OF THE RETINA. (Max 



