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. 



A 



FiQ. 28. — Diagram of photogenic organ of Nyctipkanes Conchii, to show pathways of 

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

 light cells; rf. refractor; /, focus; I, lens; A-A, axis; ai-Oi, bi-bt, light rays reflected from H; 

 ci-ci, light rays passing directly outward; di-dg and ci-en, 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 



