74 W. H. TALIAFERRO 
that the planaria practically always turned directly from the 
light without trial movements. 
1. Extraneous reflexes during orientation. After a given speci- 
men is oriented and is proceeding away from the source of illum- 
ination there are a number of different motor activities that can 
be noted. ‘Two of these, although they do not seem to play any 
ee aoe 
ALD 
aid be EM 4 
=) 
s A 
> 
My 
Fig. 5 Diagram representing orientation to light in normal specimens and 
‘wandering reflex.’ The arrows x and y indicate the direction of the rays of 
light. A, B, and C, indicate path of specimen. 1, 2, 3, 4, and 5, successive posi- 
tions of specimen; w, point of beginning of ‘wandering reflex.’ When specimen 
reached position 2 the light y was intercepted and light x turned on. 
significant part in the normal process of orientation, will be de- 
scribed here because they later become of great interest in other 
reactions to light. The first of these I have designated the 
‘wandering reflex.’ After an animal is oriented, it takes a fairly 
straight course for a certain distance (1 to 4 em.), then it begins 
to wander toward the right or left. If the animal in this wander- 
ing turns far enough to allow the rays of light to enter the pig- 
