SLUGS AS MYCOPHAGISTS 233 



maximus species. Doubtless, the slugs in woods are also attracted to 

 fungi from a distance of many feet. In view of my observations on 

 Limax maximus, the success with which slugs in woods find out the 

 fleshy Hymenomycetes can no longer be a matter for astonishment. 

 Experiment VII. On September 12, I made a fourth experi- 

 ment with hymenomycetous fruit-bodies. On this occasion I used 

 the Russula nigricans and Cortinarius caninus heaps alone, as the 

 Boletus scaber fruit-bodies had now become thoroughly decom- 

 posed. I set the two heaps of fruit-bodies on the gravel 4 feet 

 apart and each 21 feet distant from the place in the border from 

 which the slugs usually issued on their nocturnal forays ; but the 

 new position of the fungi was such that the slugs, if they sought 

 the fungi, would be obliged to travel not in the direction taken 

 during the previous two nights but in a direction making there- 

 with an angle of 45 (Fig. 82, no. VII). The night was very still, 

 and dark ; there was no moon, and overhanging trees shut out 

 from that part of the gravel which the slugs would be obliged to 

 cross even the faint light of the stars. At 11.30 P.M., with the help 

 of a taper I found a slug moving toward the two heaps of fungi 

 and only 9 feet distant from them. It was a Limax maximus, 

 exactly resembling the two I had seen the previous night, and its 

 four horns were spread out in the air as though they were being 

 used to detect the direction from which the odour of the fungi 

 was coming. I could see by the slime-trail upon fallen leaves and 

 gravel stones that the slug was making a gentle sweep toward the 

 Russula nigricans fruit-bodies and that it had kept upon a steady 

 course since it had left the border. .Next morning, I found that 

 the Russula nigricans fruit-bodies had been visited by two slugs 

 during the night, for there were four slime-tracks passing between 

 them and the border. Moreover, one large cavity and two smaller 

 ones had been made by the slugs in one of the pilei. By careful 

 tracking, I found that one of the slugs which we will assume was 

 homeward bound, after feeding upon one of the Russula nigricans 

 fruit-bodies, had made a detour and had visited the heap of 

 Cortinarius caninus fruit-bodies. Here it had crept on to one of 

 the pilei and tasted the gills, and then it had retired by a somewhat 

 sinuous course to the border from which it had set out, 21 feet 



