88 Transactions British Mycological Society. 
partial to fungus food, that Limax arborum is not a fungus eater, 
and that Agriolimax agrestis has no partiality for this food. 
2. The so-called poisonous and non-poisonous fungi have no 
relative effect upon slugs, although Coprinus micaceus killed 
those slugs left with the decomposing material, and Arion ater 
upon two occasions died after devouring with avidity Russula 
Nigh 
Those fungi possessing cystidia, such as Imocybe rimosa and 
Ee cervinus are readily eaten. Buller (1909, p. 18) states 
that the significance of cystidia does not appear to have been 
elucidated with any certainty. Possibly in some cases they 
serve to protect the fruit bodies from slugs or other animal 
parasites. In certain Russulae they do not seem to render the 
gills unpalatable to slugs since the species of this genus are 
invariably attacked by them, although we find in the case of 
green plants that prickly or hairy investments and hard 
siliceous material are a protection against molluscan teeth. 
Cultivated plants generally in this respect being not so ade- 
quately protected are more readily attacked. Those species of 
Graminaceae, Equisetaceae and Cyperaceae, where minute aci- 
cular crystals of calcium oxalate are present, act as an irritant 
in the mouth of mollusca. 
4. The chemical defences in green plants, such as acrid juices, 
alkaloids, nauseous secretions, etc. are a deterrent against slugs, 
yet fungi containing alkaloids such as Amanitae and acrid 
juices such as Russulae are not avoided. However, certain 
fungi having a viscid exterior such as Gomphidius viscidus and 
Hebeloma mesophaeum are refused, yet the viscid Stropharia 
aeruginosa is devoured. Buller (/.c.) says that the presence of 
nauseous or distasteful substances in the cellular structure 
appear to be protective against slugs. 
5. Slugs are partial to all the species of Russulae and the 
poison that affects man has quite a diverse effect by reason of 
the chemical or physiological constitution of the eee and the 
simplicity of the nervous system. 
6. They refuse tough and hard fungi, such as Sclevadenane 
vulgare and Panus stypticus. Johnson (1920) says of Panus 
stypticus “‘one of the many fungi eaten by slugs: they cause 
the rapid disappearance of young sporophores and bite large 
pieces out of mature ones.’’ This refers to natural conditions. 
7. In conclusion, there appears to be no special property in 
fungi that makes them objectionable, or, on the other hand, 
that makes them attractive as food. Buller (/.c.) gives the results 
of experiments with three species of slugs, viz. Limax maximus, 
Arion subfuscus and Agriolimax agrestis, upon twelve species of 
fungi and these generally agree with those in the appended table. 
