232 RESEARCHES ON FUNGI 



was not kept up and there was a great waste of time, for during this 

 period the net advance of the slug toward the fungi was only 4 feet. 

 The slug, as the track showed the next morning, seems, during 

 these two hours, to have wandered more or less round and round 

 in a knotted manner as if it had had some difficulty in detecting the 

 scent of the fungi. As it happened, the slug was obliged to cross 

 the line where the heaps of fungi had lain during the previous 

 night and day, and it is therefore possible that the fungi had in 

 some way scented the ground and that the scent had misled the 

 slug. It is also possible that variations in air-currents took place 

 in such a way as to send the odour of the fungi in the heaps toward 

 the slug only very intermittently. But, whatever may be the true 

 explanation, it is certain that between 11 P.M. and 1 A.M. the slug 

 lost much time and spent a considerable amount of energy in 

 fruitless wandering. 



There was nothing upon the gravel for the slug to eat except 

 the fungi I had placed there and, if the slug had continued in the 

 direction in which it set out without finding the fungi, it would 

 have traversed a gravel desert 60 feet across. 



At 2 A.M., as soon as I had found the slug which had been under 

 observation upon a Russula nigricans fruit-body, I hunted care- 

 fully over the gravelled area for other slugs. I could find one 

 more slug only another Limax maximus which had come out 

 of the border and was heading straight for the row of fruit-body 

 heaps from which it was only 8 feet distant ; but whether or not 

 this second slug ever reached one of the heaps I cannot say, as at 

 2.5 A.M. I retired to bed and, in the morning, could not clearly 

 distinguish the trail. 



In the morning of September 12, I found that the slug which 

 had visited the Russula nigricans fruit-bodies was no longer to be 

 seen upon the gravel. Doubtless, it had once more retired to the 

 border. It is probable that the return journey could not have been 

 accomplished in less than two hours. It appears, therefore, that 

 our Limax maximus, with the object of feeding upon a fungus and 

 then returning home, must have spent some six or seven hours in a 

 single night in wandering over the gravel where the fungus was. 

 Such an effort shows how strongly fungi attract slugs of the Limax 



