THE SENSORY RESPONSES OF CHITON 



231 



and then the effect of cutting off the colored light was deter- 

 mined. The transmitting regions of the spectrum for the color 

 filters used are given in table 4. These values are of course not 

 very precise. 



The red filter transmitted fight that seemed about twice as 

 bright as that coming through the blue. Nevertheless, the re- 

 actions obtained upon shading chitons through these filters 



TABLE 4 

 Regions of spectrum transmitted by certain color filters 



were sufficiently clear cut to be of some use. Responses pro- 

 duced by cutting off the fight coming through the green or the 

 blue screen were equal in amplitude to those obtained in sunlight ; 

 whereas the red and yellow lights, when occluded, led to quite 

 obviously weaker responses. This is also the case in the shading 

 reactions of the shore barnacle (Crozier, '15 b, p. 273; the same 

 fight filters were used). 



Chitons of all sizes (ages) and from every type of habitat give 



