COPRINUS LAGOPUS 319 



If a scale is removed from a pileus which is about to expand 

 and is examined with the microscope (Fig. 139), it is found to have 

 the larger cells of the cell-chains next to the pileus-flesh and the 

 smaller at the scale's free end. Whilst the pileus is increasing in 

 size and thus causing the veil to split into scales, many of the cell- 

 chains become more or less loosened or broken away from the 

 pileus-flesh. For this reason, and also owing to the extreme 

 delicacy of the cell-chains of which each scale is composed, the 

 scales become very fugacious, the slightest rub removing them from 

 the pileus, and exposure to dry air causing them to wither. Par- 

 ticularly during rain in the open, but also under laboratory con- 

 ditions (Figs. 133, oldest fruit-body, 134, and 136, pp. 305, 307, 

 and 311) the scales in older fruit-bodies tend to disappear com- 

 pletely ; and sometimes on an expanded pileus no trace of them 

 can be found. 



The shape and size of the cells on the top of the pilei are im- 

 portant aids in distinguishing species of Coprinus.from one another. 

 On this account I shall here add a few more details regarding the 

 cell-chains of Coprinus lagopus. The largest cells in a chain tend 

 to be elongated-barrel-shaped or fusiform (Fig. 141), and their 

 absolute size tends to vary directly as the size and vigour of the 

 fruit-body which produces them, the largest fruit-bodies having the 

 largest cells and the smallest fruit-bodies the smallest cells. The 

 variation in size of the largest cells in the cell-chains is indicated 

 pictorially in Fig. 141 by means of comparative camera-lucida 

 sketches. The cells nos. 7, 8, and 9 in A were the largest cells in 

 a cell-chain of a fruit-body of medium size, the cells in B the corre- 

 sponding cells for a large fruit-body, and the cells in C and D the 

 corresponding cells for two very small fruit-bodies. In two well- 

 developed fruit-bodies, one belonging to Cop-imis lagopus and the 

 other to C. macrorhizus, it was found that the largest cells in the 

 cell-chains of the former species were distinctly stouter than those 

 of the latter species. 



When the cells in a cell-chain of Coprinus lagopus are fully 

 grown, they have very thin cell-walls enclosing a very thin lining 

 layer of cytoplasm and a large central vacuole filled with clear and 

 colourless cell-sap. Sometimes, however, in addition to lining the 



