322 JOURNAL OF CONCHOLOGY, VOL. I3, NO. II, JULY, I912. 



track was nioie of the ordinary character, and further observation 

 proved what I had suspected, that the curly portions were spots where 

 the slugs had paused to browse on that green lichen which covers old 

 walls and palings. These feeding places leave permanent scars where 

 the lichen has been eaten away, and may be seen all over suitable 

 surfaces months after the shiny mucus has perished. 



When a freshly made feeding track is examined it will be seen to 

 be crossed closely with semicircular mucus lines, which give the track 

 a scaly appearance, reminding one of the ventral surface of a snake's 

 slough. I am still in doubt as to how these lines are made, but after 

 much careful watching it would seem that they are formed by the 

 mucus left round the edge of the front of the foot as the animal keeps 

 shifting its position forward in the act of feeding, or else by the edge 

 of the mantle which overhangs the head while feeding. 



There is no mistaking these tracks when once seen. My friend, 

 Mr. C. Oldham, and I tested the correctness of the diagnosis in June 

 last, visiting a series of walls and palings at night where we had 

 noticed the tracks during the day, and in every case we found this 

 species to the exclusion of any other. 



The typical travelling track of L. flavus is also distinct from that of 

 other species, being thinner, more disconnected, and altogether more 

 erratic than that of L. maxiinus. Both species are "homers," but 

 there is the following difference in their methods of performing the 

 return journey — L. flavus often crosses the outward track two or three 

 times, whereas the return track of L. inaximus very rarely crosses the 

 outward track more than once. 



Limax flaims is not generally considered very common or abundant, 

 escaping notice by its nocturnal habits, but this impression -often 

 becomes modified when the characteristic and quite diagnostic tracks 

 are looked for in suitable places. 



Since the above was written, Mr. Oldham has shown me a large 

 number of similar tracks on beech trunks in Herts., where L. flavus 

 has not hitherto been observed, but where Z. arborum is very com- 

 mon. The mucus of the tracks had perished, but the scars seemed 

 too large to have been made by Z. arborum, nor have I observed 

 Z. arborum to make tracks of this character. Z. flavus hides very 

 effectively in the daytime, while Z. arborum is usually found in the 

 crevices of tiie trunks, and I think if the trees were visited at night 

 Z. flavus would be found. 



