PRELÏMINARY DATA FOR THE ELABORATION OF THE VISUAL CODE 661 



Fig. la 



Fig. lb 



sec. F. 



Fig. la. 



Schematic drawing of the distribution of primary (prim. F), secondary (sec. F) and tertiary (tert. F) 

 fibers on and within the Lamina (La) and Medulla externa (Med. ext.) 

 and of the neurommatidia (N.O.) in the Lamina. 



Fig. lb. 



Schematic drawing of an optical cartridge in the Lamina, tr. nf transverse 

 and neurosecretory fibres, other abréviations see figure la. 



