THE RETINA 



31 



WMmB 





y^mMA'AAKi 



Fig. 25. Scheme of the structure of the primate retma as shown by Polyak, 

 1941, Chicago University Press. liCgends and designations are given in foot- 

 note 1. 



two systems become intimately united into a single compact 

 tissue pattern (Figures 25, 26, 27, 28). ^ 



According to Polyak, the rod system is composed of three 

 links as follows (Figure 27, A-C): the rods (a), all of the 



1 In order to facilitate the interpretation of Polyak's illustrations which are re- 

 produced in Figures 25, 26, 27, 28 a list of his legends and their designations are 

 given as follows: 



k — amacrine cell 



1 — internal association cell (amacrine cell) 

 m — diffuse ganglion cell 

 n — shrub ganglion cell 

 o — diffuse ganglion cell 

 p — diffuse ganglion cell 

 r — diffuse ganglion cell 



a — rod 

 b — cone 



c — horizontal cell 

 d — mop bipolar cell 

 e — brush bipolar cell 

 f — flat bipolar cell 

 h — midget bipolar cell 

 i — centrifugal bipolar (amacrine) cell s — midget ganglion cell 



