10 



Hooker: Physiological observations 



Fig. I, a and b, with Fig. 2, d and e, illustrates this. The most 

 apical part which elongated during the process of bending is the 

 last to regain its original position. The basal portion, however, 

 does not stop increasing its length until the entire tentacle is 

 straight. At the end of the reaction, after 23 hours and 10 

 minutes, the tentacle measured 3.37 mm. It had therefore grown 

 during the process of bending and unbending 0.43 mm. (See 



Fig. 3. Side views of the same tentacle before and after the reaction, to show 

 the increase in length, X 22. a is the same as Fig. i, a; 6 is the same as Fig. 2, /. 



Fig. 3). A control tentacle which had not been stimulated meas- 

 ured before and after the experiment 2.57 mm. Another measured 

 2.6 mm. They had not grown a measurable amount during the 

 interval. 



Fig. 4 is a graphical representation of the growth of the 

 tentacle. The elongation of the abaxial side is shown by the 



Fig. 4. A graph representing the reaction shown in Figs, i and 2, drawn 

 according to data in Table I. See text for explanation. 



