STRUCTURE OF THE RETINA. 



271 



part, the cone proper, which is directly prolonged into a nucleated 

 enlargement, from the farther side of which the cone-fibre, considerably 

 thicker than the rod-fibres, passes inwards, to terminate by an ex- 

 panded arborisation in the outer molecular layer. The cone proper, 

 like the rod, is formed of two segments, the outer of which, much the 

 smaller, is transversely striated, the inner, bulged segment being longi- 

 tudinally striated. The inner ramified ends of the rod-and-cone fibres 

 are believed to come in contact with the arborisations of the inner 



m.e.l. 



FlG. 303. PlGMENTED EPITHELIUM OF 

 THE HUMAN KETINA. (M. Schultze.) 



(Highly magnified.) 



a, cells seen from the outer surface with clear 

 lines of intercellular substance between ; 6, 

 two cells seen in profile with fine offsets ex- 

 tending inwards ; c, a cell still in connection 

 with the outer ends of the rods. 



FlG. 304. A FIBRE OF MtJLLER FROM THE 

 HUMAN RETINA, ISOLATED. (Henle.) J-- T A 



b, base of the fibre ; n, its nucleus ; m.e.l., mem- 

 brana limitans externa ; e.m.l., external mo- 

 lecular layer. 



t.in. I. 



granules, and through these elements and their arborisations in the 

 inner molecular layer a connection is probably brought about with the 

 ganglionic-cells and nerve-fibres of the innermost layers. There 

 appears, however, to be no anatomical continuity between the several 



