SLUGS AS MYCOPHAGISTS 229 



toward an expanded fruit-body of Phallus impudicus and that, 

 upon coming in contact with the fruit-body, it feeds upon the stipe. 



I employed Phallus impudicus for my first experiments upon the 

 chemotaxis of slugs because of its very powerful odour and the 

 convenience with which I could procure and handle its fruit-bodies ; 

 but I have found that similar experiments can be performed with 

 Boleti and Agaricineae. 



Experiment IV. On September 8, I procured three fresh 

 fruit-bodies of Boletus scaber from a wood and, in the evening of 

 September 9, placed them upon the gravelled area at a distance 

 of 10 feet from the border. During the night a slug came from the 

 border across the gravel to the fruit-bodies and ate three holes 

 in the top of one of the pilei. A similar experiment made at the 

 same time with a large fruit-body of Russula heterophylla was 

 also successful. 



Experiment V. The next evening, September 10, about 8 P.M., 

 I placed upon the gravel three little heaps of hymenomycetous 

 fruit-bodies. In the first heap were the three fruit-bodies of Boletus 

 scaber which had been used the night before, in the second three 

 fruit-bodies of Cortinarius caninus, and in the third three fruit- 

 bodies of Russula nigricans. Each heap was made at a distance 

 of 12 feet from the border and the three heaps were in a row, the 

 central heap being that of Boletus scaber and the intervals between 

 the heaps being 4 feet. Having had considerable difficulty in some 

 of the previous experiments in tracking the slime-trail upon the 

 gravel owing to the intermittency or thinness of the trail and owing 

 to the effects of dew, I placed some large fern leaves in a line along 

 the edge of the gravel by the border, so that, if a slug crossed the 

 line, it would leave a trail behind which could be easily detected. 

 The night was a very dark one. About 10 P.M. I went out with a 

 lighted taper to see what was happening. On examining the fern 

 leaves I found upon the leaflets a shining slime-trail, the direction 

 of which proved that the fern line had already been crossed by a 

 slug. I then hunted about on the gravel and found the slug, 

 a Limax maximus, about 4 inches long, actually on its way to the 

 fungi. The slug was already 4 feet from the border whence it had 

 come and was heading in the right direction to reach the row of 



