58 



Herbert Eugene Walter 



is in the average rate of all individuals collectively under different 

 intensities. The data for this latter point based upon the average 

 rate of ten worms (259 observations) under different intensities 

 has already been given in Table III (p. 57). The extremes in 

 rate there shown are 0.57 mm. per sec. at zero intensity and 0.75 



table rv 



Average rate of locomotion of Planaria gonocephala in successive minutes of exposure to 59 c.m. of non- 

 directive light 





I St 



2d 3d 



4th 



5th 



6th 



7th 



8th 



9th 



10th 



nth 



1 2th 



No. of records averaged . . 

 Rate in mm. per second . . 



17 

 •63 



*5 



.625 



12 7 



•5 6 5J -55 



5 

 •53 



4 



•55 



4 



•375 



3 

 •39 



3 

 •39 



2 

 .29 



2 

 • 2 5 



2 

 .29 



mm. per sec. at 39 c.m. intensity, which makes a range of 0.18 mm. 

 per sec. When the same data are rearranged to show the average 

 rate for each individual for all intensities, as in Table V, the 

 extremes are 0.49 mm. per sec. and 0.83 mm. per sec. with a range 

 of 0.34 mm. per sec. 



In fact the individual behavior of these ten worms, despite their 

 apparent similarity, was sufficiently distinct to allow each one to 

 be thereby identified. 



Turning. Attention has already been called to the fact that 

 there is less turning in light of various intensities than in the dark. 

 A return to Table I will make plain that there fails to be any 



table v 



Average rate of locomotion for each of ten worms {Planaria gonocephala) based on trials with non-directive 



light of various intensities 





1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



Average rate in eight intensities ex- 



0.79 



0.57 



0.68 



0.64 



0.83 



0.70 



0.72 



0.58 



0.49 









definite correlation between the degree of intensity of the light and 

 the amount of turning, although the least turning occurs under 

 the highest intensity. This latter point, however, rests upon a 

 very slight difference and may not be significant. It is neverthe- 

 less worth mentioning, since it is in line with the effect of the 



