day: pigment-migration in eye of crayfish. 



327 



TABLE III. 



Intensity varied. Time constant (10 minutes). Evaluations made from 

 the same observation-records as in Table II, but with reference to three graded 

 migrations exhibited by animal 28. 



R 



243.3 

 ' 95 



= 2.56 in terms of distance. 



BV = (2.56)2 R. in terms of intensity, or 

 Equation I:BV = 6.5 R 



II: BV = 5.6 R on rejecting G, K, 24, 2.5, 35 and 36. 



records first and then averaging these, yielded BV = 7.2 R; and 

 when this was included with the other determinations, the final 

 average expression for blue- violet in terms of the efficiency of red, 

 ascertained by increasing the period of exposure, became 7.4, a value 

 which is somewhat higher than that previously determined (5.6) by 

 varying the intensity. 



