SLUGS AS MYCOPHAGISTS 221 



A. hyperboreus have both been reported from Manitoba, and the 

 only other species likely to be found in such a cold northern 

 region is Philomycus carolinensis. 1 



Since fleshy fungi, e.g. Russulae, Lactarii, Amanitae, Cortinarii, 

 etc., occur in great variety and numbers in the woods of central 

 Canada, and since slugs do not occur in these woods or are very 

 rare there, it seems safe to infer that fleshy fungi, such as Russulae, 

 Lactarii, Amanitae, Cortinarii, etc., in no way depend upon slugs 

 for the dissemination or germination of their spores. 



Some Conclusions. We may conclude from the above observa- 

 tions : (1) that slugs, under natural conditions, may attack and 

 feed upon most species of fleshy Hymenomycetes occurring in 

 woods ; (2) that the attacks of the slugs often seriously interfere 

 with the production and liberation of spores by individual fruit- 

 bodies ; (3) that most species of fleshy fungi are in no way pro- 

 tected against slugs ; (4) that slugs feed with impunity on fungi 

 which are poisonous to man ; and (5) that very many species of 

 fleshy fungi do not depend upon slugs for the dissemination or 

 germination of their spores. 



The Finding of Fungi by Slugs. Before eating a fungus, a 

 slug must first find it. Now, according to zoologists, the common 

 slugs of English fields and woods, e.g. Limax maximus and Arion 

 ater, although possessing eyes, can see clearly for a distance of only 

 1 or 2 mm. and find their food chiefly by their sense of smell. 2 

 We must therefore suppose that slugs find the fungi upon which 

 they feed chemotactically, i.e. by changing their direction of 



1 Agriolimax agrestis, the common field slug, introduced from Europe, is now 

 widely distributed in eastern North America and has become a veritable pest in 

 gardens in some parts of the United States (vide F. C. Baker, " A Mollusc Injurious 

 to Garden Vegetables," Science, N.S., vol. xliii, 1916, p. 136; also "A Molluscan 

 Garden Pest," Science, N.S., vol. xlvii, 1918, pp. 391-392). I myself have seen 

 this small slug in a greenhouse at Winnipeg and have had other specimens brought 

 to me from a Winnipeg garden ; but Winnipeg gardeners in general are unacquainted 

 with it, and, so far as I know, it has never yet been found in woods away from 

 habitations. A. agrestis is very partial to chlorophyllaceous food, e.g. lettuce, 

 cabbage, etc. ; but, as the experiments of Dr. W. T. Elliott (communicated in litt.) 

 and others have shown, it has no great liking for fungi and is only occasionally a 

 mycophagist. 



2 V. Willem, Arch. Biol. XII, 1892, p. 57, cited from A. H. Cooke, Cambridge 

 Natural History, Molluscs, 1895 ; p. 185. 



