MOVEMENT TOWARD LIGHT IN COELENTERATES 155 



There is however in positive specimens a tendency to retain 

 the position in which the oral end is most highly illumi- 

 nated. This was demonstrated as follows: 



Ten specimens were exposed in the rectangular aquarium 

 in the dark room. As they traveled toward the light the 

 direction in which they faced was recorded at intervals. 

 These records appear in the table given below. 



TABLE I. 



' In making the table all those specimens in which the oral end was near a plane passing 

 through the foot and perpendicular to the direction of the rays were recorded in column 4; 

 all in which this end was definitely to the right, i.e., toward the light, in column 2; and those 

 to the left, in column 3. 



The table shows very clearly that the oral end of the ten 

 specimens studied was directed approximately toward the 

 source of light nearly three times as much as from it. If 

 the direction of locomotion depended merely upon the 

 direction in which the oral end points, one would expect 

 these organisms in the positive state to loop from the source 

 of light more than one-third as often as toward it. This 



