--26 



Table No. 1. 



Volvox Reactions to Sunlight behind Wratten Colored Filters. 



Filter 



70 

 71 

 72 

 73 

 74 

 75 

 76 



Control. 

 Table No. 2. 

 70 

 71 

 72 

 73 

 74 

 75 

 76 



Control. 



Wave Length in 

 Angs t r o m un its. 



- 7000 



3~c[ OO (o^OQ 

 5<o oo - y<?o 



4-700 - 



4-066 47OO 



H- o o o 



QO - 



- (c^OO 

 5(0 00 



s'Zoo - ^6,00 



y-ooj 



Lj-Odi) JOOO 



Color 



y ) 



Sxposure 



t 



Table 1 shows that wave lengths from 4000 to 4700 A. are de- 

 cidedly more powerful in directing the movements of Volvox than are 

 those of the remainder of the visible spectrum, 4700 to 7000 A. U. 

 There is an indication, however, that some individuals respond to the 

 long waves. 



Table 2 shows that the stimulating efficiency of the difierent 



