1914] JOLIVETTE—PILOBOLUS 109 
The entire surface{of the culture, which was 5 cm. in diameter, was 
exposed. Before each of the openings, at equal distances, was 
placed one of the two lights to be tested. The angle at which the 
lamps were placed was such that the spot of light from each lamp 
struck symmetrically the open surface of the culture. 
The series of experiments was begun with a 32-candle-power 
carbon filament lamp before one opening and a 20-watt tungsten 
before the other. The first experiment gave a total of 92 sporangia; 
31 sporangia were discharged toward the carbon filament and 61 
toward the tungsten. In the second experiment 163 sporangia 
were discharged; 68 toward the carbon filament and 95 toward the 
tungsten. In the third experiment 387 out of a total of 784 spo- 
Trangia went to the tungsten. Of the 1116 fired in the fourth experi- 
ment, 113 went to the carbon, 1003 to the tungsten. The next 
experiment shows a total discharge of 228 sporangia; 78 toward the 
carbon, 150 toward the tungsten. A new carbon lamp was put in 
the place of the old in the seventh experiment, but again a very 
much larger percentage was aimed toward the tungsten; 589 spo- 
Tangia were fired, the ratio standing 168 toward the carbon as 
against 431 toward the tungsten. The data for this set of experi- 
ments are given in complete form in table IV. From this table 
a comparison of the accuracy of aim of Pilobolus toward the carbon 
and tungsten lamps can be made. 
TABLE IV 
g 
ro) ' 
3 q 
os 
Total | s 
me #8 
¥ 7m 
hp g° 
ONUSGCR CAR eee ie 
92 |.. 
Cotas ran Gatne ae ee Io} 6 3) 7) 42! 9 
ra oe ae) Re, eae nek A Ee OP gh oe eee | Oy Oe arene rj} |} 3} 15) 54) 20)-. is 
Po i te a ee hae 6 | 64|203 | 86] rs} 6 | 4 | 2| 2| 5 | 3] 40| 253] 88) 3 dt As 
io a eee ae eee 3 | 19] 69| ro} 3/..., 2 | 2| 3 | 5 | 17|270| 607|\179| 18 
804 Tkerews -| 15] 47 | 12 4 4 6| 22] ror) 17 
~ =a oa Bias r}...| 30/13] 21} 7) 1 | 2/2} 9} 58 503/130 41 
tes|ese 1 | 7 | 48) 78) 24) 31 4] 2|3| 6) 8] 8| 69) 258 63) 4) 1 | 2 
es ee en A i ee 
Of the 31 sporangia discharged toward the carbon lamp. in 
the first experiment, 19 (61 per cent) struck the glass over the 
tem. vertical strip containing the opening. Of the 61 sporangia 
