80 



THE NATURE OF ANIMAL LIGHT 



30) chromatophores are found about the region where the 

 light is emitted and these no doubt serve as color filters. 



Fig. 28. — Diagram of photogenic organ of Nyctiphanes Conchii, to show pathways of 

 light rays arising in the light cell layer (after Trojan), p, pigment; ri, inner reflector; Ip, 

 light cells; rf. refractor; /, focus; I, lens; A-A, axis; ai-at, 61-64, light rays reflected from ri; 

 CI-C4, light rays passing directly outward; di-ds and ei-eo, light rays which have passed 

 refractor and lens respectively. 



There are also an abundant blood supply and nerves pass- 

 ing to the organ. Figs. 30 and 31 are sections through 

 light organs of fishes. 



We thus see that light organs may be very simple and 



