TYPES OF AGARICINEAE 241 



on each gill. The most advanced basidia are always at the lower 

 free edge of each gill, while the least advanced basidia are always 

 at the upper fixed edge of each gill. Each small area of the 

 hymenium (one-tenth of a square mm.) does not produce a number 

 of successive generations of spores, but all the basidia on the area 

 come to have ripe spores upon their sterigmata almost simultaneously. 



(5) Discharge of the Spores. The spores in the Inaequi- 

 hymeniiferous Type of fruit-body are discharged in succession 

 from below upwards on each gill. A zone of spore-discharge moves 

 slowly from the lower edge to the top of each gill. The spores 

 are shot more or less perpendicularly outwards from the hymenium 

 in the zone of spore-discharge into the interlamellar spaces, and 

 they then fall down slowly between the lamellae and escape in the 

 same manner as in the Aequi-hymeniiferous Type. 



(6) Autodigestion of the Gills. As the zone of spore-discharge 

 moves from below upwards on each gill, it is followed very closely 

 by a zone of autodigestion which completely destroys those parts 

 of the gills which have become spore-free. The zone of auto- 

 digestion, therefore, moves slowly from below upwards on each gill 

 and eventually destroys the whole of each gill. 



In Volume III, in which the development of various Coprini 

 is treated of in detail, I shall endeavour to show that the ripening 

 and discharge of the spores from below upwards on each gill and 

 the autodigestion of each gill from below upwards are correlated 

 with the successful liberation of the spores from parallel-sided 

 ageotropic gills. 



(7) The Pileus-flesJi. This is relatively thin, even in large 

 fruit-bodies. It becomes involved along with the gills in the 

 process of autodigestion and is therefore destroyed centripetally. 

 In consequence of this, in larger fruit-bodies, drops of a dark 

 fluid the products of autodigestion are often to be observed 

 hanging from the pileus-rim when the period of spore-discharge 

 has become well advanced. 



The two general Types of fruit-body organisation will be compared 

 and contrasted after the Sub-types have been described in detail. 



The Characters of the Sub-types. The Sub-types of Type I are 

 based almost solely on differences in the structure and arrangement 



