THE SPHAEROBOLUS GUN 307 



veloped by a thin pseudoparenchymatous layer (peridial layer, 

 no. 6, Fig. 146, a, p. 295, and Fig. 151). If such discharged glebal 

 masses are examined with the low power of the microscope they are 

 found to have, upon their exterior, lighter areas which mark the 

 original position of the passage-ways. The passage-ways never occur 

 in the upper half of a glebal mass (Fig. 153, A) but always in the 

 lower half (Fig. 153, B). An examination of the lower halves of 

 discharged glebae revealed the fact that the passage-ways vary much 

 in size, number (three to ten), and arrangement (Fig. 153, C, a-i). 



The histological structure of an unopened fruit-body which was 

 approaching maturity and would have discharged its glebal mass 

 next day is shown in Fig. 154, where A represents a median-vertical 

 section of the fruit-body and B a series of tangential sections. The 

 six layers of the peridium, nos. 1-6, and part of the gleba, g, will 

 now be described in detail. In the mycelial layer, no. 1, the hyphae 

 have thin walls and bear clamp-connexions. In the gelatinous layer, 

 no. 2, the hyphae are very slender, bear clamp-connexions and are 

 embedded in a gelatinous matrix formed by the swelling of their 

 outer walls. In the thick pseudoparenchymatous layer, no. 3, the 

 cells are swollen and rounded and separated by air-spaces. In the 

 thin fibrous layer, no. 4, the hyphae are slender, thick-walled, inter- 

 woven, and disposed mostly in a tangential direction. In the 

 palisade layer, no. 5, the cells are radially elongated, relatively 

 thick- walled, and mutually adherent. In the thin pseudoparenchy- 

 matous layer, no. 6, the cells are small, rounded, and separated 

 by air-spaces. The gleba g contains peripherally a layer of rounded 

 cells a a known as cystidia and within is divided into small chambers 

 several of which are in view. The partition walls of the chambers 

 are made up of ordinary thin-walled hyphae b b which may bear 

 clamp-connexions and of much-swollen fat cells c c whose glutinous 

 contents have not yet been liberated but which eventually will be 

 set free and come to form a matrix in which the spores, gemmae, 

 and cystidia will be embedded. Loosely scattered in the chambers, 

 from which the basidium-bodies have now disappeared, are : very 

 numerous, oval, thick-walled spores d d ; less numerous, thin-walled, 

 more or less elongated gemmae e e ; and a few spherical cystidia like 

 those at a a. 



