226 RESEARCHES ON FUNGI 



in nature, are dependent on the existence of particular herbivorous 

 vertebrates. It seems likely that the extinction of large Herbivora 

 in past geological ages has often brought about the extinction of 

 some of their associated fungi. With regard to the fruit-bodies 

 it may be pointed out that, as in Coprinus niveus, Panwolus 

 phalxnarum, Anellaria separata, and Galera tenera (cf. Figs. 25, 

 p. 68, and 32, p. 80), they usually have more or less campanulate 

 pilei situated on long and slender stipes. The latter, at least in 

 many Coprini and probably in the other coprophilous genera, are 

 at first heliotropic. This enables the compact young pilei to be 

 pushed out into the open from beneath or between balls of horse 

 dung, &c., so that afterwards, when the stipes change their 

 physiological properties and become negatively geotropic instead 

 of heliotropic, the pilei are placed in such a position that they 

 can expand and shed their spores into the air free from all obstacles. 

 The length and relative slenderness of a stipe are well suited to 

 enable that structure to thread its way outwards to the light by 

 a process of growth, and afterwards to make a geotropic curvature 

 by which the pileus can be brought into an advantageous position 

 for shedding its spores. 



Slugs and Hymenomycetes. Many slugs find certain fruit- 

 bodies exceedingly palatable and often devastate them in a wood 

 to a surprising extent. One sometimes has difficulty in obtaining 

 a single intact specimen of Russula emetica, R. citrina, Amanita 

 muscaria, &c., even where they occur in considerable numbers. 

 The gills are particularly relished, but large pieces of the pileus 

 flesh are also frequently devoured. 



Voglino 1 has made an investigation upon the relations exist- 

 ing between slugs and Hymenomycetes, and has arrived at a 

 very interesting conclusion. His chief observations were as follows. 

 The digestive tracts of slugs collected in some pine woods were 

 found to contain germinating spores of the following species: 

 Tricholoma humile, Mycena alkalina, Inocybe fastigiata, Lactarius 

 deliciosus, and species of Russula. Slugs were fed with fruit-bodies 

 of Russulse and Lactarii, and subsequently numerous germinating 



1 P. Voglino, "Richerche intorno all' azione delle lumache e dei rospi nello 

 sviluppo di Agaricini," Nuovo Giornale Botanico, vol. 27, 1895, pp. 181-185. 



