104 BOTANICAL GAZETTE [FEBRUARY 
the culture fire toward the left opening and vice versa. Some of 
this may be due to reflection from the glass. 
TABLE II 
The culture maa ance and facing the two openings; a glass plate pees oe openings; a second 
glass plate at right angles @ the waters e B of the a tur e- a data i cont the plates given 
in the first pa of the nh lture are retested to by the 
marks *, f, a 
to oo a rey 
xi | i ‘3 §| Date 
8 a a i z 
3S a a 3 
= (Ss) ro) 4 
26 ¥)O6} 8 |} a13 21211 1* | 6/15/10 
7130 P.M. 
7 I 2 red Be Ve Be at |6/16/’r0 
7:35 P.M 
38 r1}4)]7]9 I I Se hepa as 3t | 6/17/10 
*Sporangia discharged on glass at " .-.[--[ 2 |.../...[ 2 [...[-..[ Surface of glass to left of culture 
right angles to surface of culture}|7 | 5 | 3 « eee Msg so 
ft Sporangia discharged on glass at i. 3 sd oe tet pegs 
right angles to surface of culture!\2 | t | 2} 2{1/...]...|...| 2 . pitta fs 
a. —. on glass at “ ee gy eet "is 
of culture bis eee Te Pe oir sem SNe peers mee! “ « “ “ yight “ a 
The behavior of Pilobolus when given two equal sources of light 
but with the angle between the two sets of incident 
light rays varied 
The box used for this set of experiments was made of redwood 
and measured 120 cm. long by 45 cm. wide and 35 cm. high. 
hinged cover was so rabbeted as to be light-tight and was supplied 
with ice box catches in order to fasten it down tightly. At one 
end of the box, 14 cm. from the base, was an opening 9 cm. wide 
all the way across from side to side and so arranged with galvanized 
iron rabbets as to carry strips of galvanized iron 10 cm. wide 
which just closed the opening. These strips contained the openings 
through which the light was admitted to the culture. They were 
made of galvanized iron so that they would be thin enough to 
avoid shadows being cast by the rim of the openings. The openings 
were I cm. in diameter and their centers were the following dis- 
tances apart: 1cm., 2cm., 3cm., etc. The inner surface of the 
slide containing the Spening was flush with that of the end of the 
