574 RESEARCHES ON FUNGI 



of the gills ; (3) the existence of the interlamellar spaces is secured by 

 the cystidia, each of which is attached by its two ends to two opposite 

 gills and acts as a stay or distance-piece ; (4) the interlamellar spaces 

 continue to be bridged by the cystidia during the discharge of the spores ; 

 and (5) the basidia are dimorphic— long and short. Included within 

 the Atramentarius Sub-type are : Coprinus atramentarius, C. picaceus, 

 C. stercorarius, C. narcoticus, C. macrorliizus, and C. urticaecola. 



From the point of view of the production and liberation of the 

 spores the author describes the fruit-body of Coprinus atramentarius 

 in detail. 



The gills of Coprinus atramentarius are very thin and also very broad, 

 and they are locked together by numerous cylindrical cystidia which 

 bridge the interlamellar spaces. When one considers the shape, size, 

 structure, position, and number of the cystidia in the interlamellar 

 spaces of a young pileus and also the extraordinary thinness, breadth, 

 and mechanical weakness of the gills when detached from the cystidia, 

 one is justified in concluding that the cystidia are unicellular organs 

 which function by holding the gills apart, thus maintaining the exist- 

 ence of interlamellar spaces in which the spores can develop without 

 mechanical hindrance. 



The gills of Coprinus atramentarius continue to be interlocked by 

 the cystidia bridging the interlamellar spaces throughout the spore- 

 discharge period. The autodigestion of the gills, so far as the basidia, 

 paraphyses, subhymenium, and trama are concerned, takes place as 

 in C. comatus or C. sterquilinus. However, the cystidia do not undergo 

 autodigestion at the same time as the basidia and paraphyses : they 

 destroy themselves in succession from below upwards on each gill, and 

 each one disappears a few minutes before the basidia in its immediate 

 neighbourhood become involved in the upAvard-progressing zone of 

 spore-discharge. Owing to their early autodigestion, the cystidia can- 

 not possibly hinder the fall of the spores and prevent the escape of these 

 bodies from between the gills. The autodigestion of individual cystidia 

 was found to take 10-15 minutes. 



In a gill of Coprinus atramentarius, from above downwards, during 

 the spore-discharge period, seven zones can be distinguished : (1) a zone 

 with less ripe spores in which the cystidia are fully turgid and are 

 functioning as distance-pieces keeping the gills apart ; (2) a zone with 

 riper spores in which the cystidia are disappearing owing to auto- 

 digestion ; (3) a zone of ripe spores from which the cystidia have already 

 disappeared ; (4) a zone of spore-discharge ; (5) a zone which is spore- 

 free ; (6) a zone of autodigestion in which the basidia and paraphyses 

 are disappearing ; and (7) a liquid film at the extreme gill-edge, contain- 

 ing tlie products of autodigestion and the Avasted spores. 



The small amount of pileus-flesh in the Inaequi-hymeniiferae, e.g. 

 Coprinus atramentarius, and the large amount of pileus-flesh in the 



