102 



THE EYE AND EAR. 



3. The Retina. 



Mount ill balsam one of the prepared sections of the j^osterior 

 part of the frog's eye : examine with low aiid high powers. 



Fig. 19. Vertical section through the posterior wall of the eye of a 

 frog : the section passes through the sclerotic, the choroid, and the entire 

 thickness of the retina, x 3(X). 



BC, red blood corpuscle : C, cone : G, nerve cell : IL, inner limiting mem- 

 brane : IM, inner molecular layer : IN, inner nuclear layer: NF, layer of 

 nerve fibres : OL, outer limiting membrane : OM, outer molecular layer : 

 ON, outer nuclear layer : P, pigment cell : PC, pigment of choroid : R, rod : 

 RF, radial or Miiller's fibre : S, the cartilaginous sclerotic. 



