480 E. J. LUND 



after the beginning of each test, so that an approximately com- 

 plete history of each piece was obtained. The drawings in 

 plates 1, 2, and 3 are camera-lucida drawings of the pieces at the 

 end of the experiments. 



Experiment 1. Trough figure 2, A, was used. Internodes 

 were cut at random from the different branches of a colony. 

 The age of the internode, that is, its relative position in the 

 stem with reference to the growing point, is indicated in part by 

 the depth of brown color in the perisarc. Apical internodes 

 have a more transparent perisarc ^than more basal pieces of the 

 same branch. One and one-half hours after cutting, the 

 pieces were placed in position in the notches on the cork plates 

 m and n, without reference to whether the apical or basal end 

 of a. piece pointed toward the anode in m. The actual orientation 

 of the pieces with reference to the direction of the electric current 

 is shown in B of plate 1. Immediately after placing the pieces 

 in position, the orientation of which was determined by chance, 

 the current was turned on and left on until the end of the ex- 

 periment, forty-seven hours after cutting and forty-five hours 

 after turning on the current. A continual stream of fresh sea- 

 water was running through m and n during the experiment. The 

 directions of the water current and the electric current were 

 the same in all the experiments, as indicated in figure 2, A and D. 

 The density of the electric current was approximately 70 5. 

 Temperature, 15 ± 2°C. 



Twenty hours after beginning the experiment growth was 

 well advanced toward formation of hydranths on both ends of 

 the internodes in the control in n. While in m the majority of 

 the pieces only showed beginnings of growth toward the anode. 



Thirty hours after the beginning of the experiment, most of 

 the pieces in n had fully differentiated hydranths, while pieces 

 in m showed only beginnings of hydranth buds comparable to 

 stages 6 and c in figure 3. 



Practically no growth had occurred on the ends toward the 

 cathode. It was also clearly evident that younger internodes 

 in m showed in general greater growth than older, more basal 

 internodes. The pieces were killed in fixing fluid and finally 



