224 PRACTICAL HISTOLOGY [XXIX 



four rows of round or oval nuclei. The cell substance 

 is inconspicuous. 



(vi) The outer molecular layer, a thin layer 

 much like the inner molecular layer (iv). 



(vii) The outer nuclear layer; the nuclei are 

 smaller and more numerous than in the inner nuclear- 

 layer (v). 



(viii) The outer limiting membrane, a well 

 defined line. 



(ix) The layer of rods and cones, probably the 

 outer and inner limbs of the rods can be distinguished. 

 Note the cones, shorter or less numerous than the 

 rods. 



(x) The layer of pigment cells enveloping the 

 free ends of the rods. 



Observe also the supporting fibres (fibres of 

 Miiller), seen as lines stretching a greater or less 

 distance between the inner and the outer limiting 

 membrane. 



8. Section of posterior part of eye of newt (osmic 

 acid vapour; Flemming's fluid; Ehrlich-Biondi stain). 

 Note 



The supporting fibres, having an expanded mem- 

 branous base at the inner limiting membrane, an 

 elongated nucleus in the inner molecular layer, and 

 stretching to the outer limiting membrane. 



The large outer limbs of the rods, and the processes 

 from the pigment cells running between them. 



9. Examine in detail the retina of the newt ( 8), and 

 compare it with the mammalian retina ( 7). Note 



