688 RAYMONP PEARFi. 



musculature^ and dies. I have never been able to produce 

 disintegration on the anode side Avith any current strength at 

 my disposal except in a single case, where disintegration 

 began in the region just behind the pharynx in a specimen 

 strongly curled up in the way described. 



In case the long axis of the planarian is parallel with the 



V 



Fig. 44. — Diagrammatic side view of a planarian subjecteil to the action 

 of a very strong constant current. 



direction of the current, and the head is towards the kathode 

 at the moment of making, with a perfectly fresh specimen the 

 effect is to cause a cessation of the gliding movement and a 

 change to a very slow crawling. The direction of the move- 

 ment is not changed. There is a well-marked contraction of 

 the anode (posterior) end of the body. The reaction of the 

 animal in this position is shown in Fig. 45, J). Yerj weak 

 currents have either no effect on a specimen in this position 

 or else may cause a very slight contraction of the ventral 

 longitudinal fibres mentioned above. 



When the long axis of the body is parallel to the direction 

 of the current, and the head is towards the anode at the 



Fig. 45. — Diagram showing tlie elcctrotactic reaction of Plan aria when 

 the long axis of the body is in line with tiie current direction, and 

 the head is towards tiie katliode. Contracted portions are indicated 

 by heavy lines. 



moment of making, the effect of a current of medium intensit}- 

 is to cause the gliding movement to stop. At the same time 

 there is a very definite contraction of the anode (head) end 

 of the body. As the current continues to act the specimen 

 begins to squirm about, and very soon gets out of line Avith 

 the current. Then the anterior end is turned toAvards the 



