78 



KINETIC HORMONES — I 



I 



■crn. 



-con.. 



-d.r.c. 



— rh. 



o/\o 



d.r.Cr 



p.r.c— 



Fig. 3-12. Three ommatidia from the compound eye of the cray- 

 fish, Camharus hartoni\a-c in longitudinal section and d-f in surface 

 view, (a) Ommatidium of a typical dark- adapted eye with pigment 

 concentrated at two levels : round the cone (con.) in the distal retinal 

 cells (d.r.c), and below the basement membrane (b.m.) in the 

 proximal retinal cells (p.r.c). The corresponding surface view (d) 



