MOVEMENTS OF THE EARTHWORM 



621 



pensedwith. During the experiments the entire surface of the 

 apparatus was kept moist. The experiments were conducted in 

 a dark room with a single electric lamp so arranged that the fixed 

 plate was completely shaded. 



In a general way the experiments were so conducted that a worm 

 crawling upon the sector was directed so as to pass on to the im- 

 movable plate while maintaining a straight course; in the mean- 

 time the sector would be turned through an arc of 10° to 45° 

 either to the right or to the left. The result of this shifting was 

 that, while the anterior part of the worm remained in the line 

 of its movement, the posterior part was more or less deflected 



Fig. 1 



from that line. Under these conditions the anterior part changed 

 its position, swerving towards the side opposite to the turning of 

 the sector, and the worm continued its movements in a new but 

 approximately straight line. These reactions of orientation with 

 no extraneous directing influence, schematically represented by 

 means of arrows in the diagram, fig. 1, are precise and constant, 

 so that, with the conditions properly adjusted, they may be re- 

 peated many times with scarcely a failure. It has been found 



