Allen and Jolivette—Light Reactions of Pilotolus. 541 
centimeters in diameter and that of the opening hut four centi¬ 
meters this brought the upper edge of the culture one centimeter 
above the upper edge of the opening. A series of daily 
records was obtained by moving the culture back from the open¬ 
ing along the median line of the box so that the distance would 
be increased two centimeters at a time, allowing it to stand 
twenty-four hours in each position. The glass on which the 
sporanges were caught was placed inside the box against the 
ao 
op er "°3 areas 
Fig. 4. 
opening as before. When the distance of the culture from the 
opening became so great that some of the sporanges did not 
reach the glass, a second pane of glass was placed on the bottom 
of the box to catch them. 
In these experiments, the bull’s eye target (Fig. 3) described 
in the last experiment was employed, with the addition of a 
horizontal line A B through the common center of the concen¬ 
tric circles. By means of this line A B it was possible to de¬ 
termine whether or not the center of distribution of the spor¬ 
anges on the glass is lowered as the distance of the culture from 
the opening is increased. The line A B, however, was not used 
in making the records in this set until the culture had been 
