516 



S. O. MAST 



TABLE 12 

 Arenicola larvae. Relation between wave-length and stimulation 



For description of table see legend table 2, p. 492. 



also be seen that the distribution in the spectrum of stimulating 

 efficiency is throughout very much like that in Euglena, the maxi- 

 mum being located almost precisely in the same place for both 

 (table 15). There is, however, some evidence indicating that 

 the effective region extends somewhat farther toward the red in 

 the former than it does in the latter. It will be seen, moreover, 

 that in the tests made with the spectrometer' slits wider and the 

 illumination consequently stronger the maximum is somewhat 

 nearer the violet. This is just the opposite from what would be 

 expected in case there were a Purkinje effect. 



Loeb and Wasteneys ('16, p. 232) maintain that in a '' carbon 

 arc spectrum" the maximum stimulating effect for Arenicola 

 larvae is ''situated in the bluish-green in the region of about 



