270 



RESEARCHES ON FUNGI 



isolated gill of either C. sterquilinus or C. comatus. This is exactly 

 what might have been expected from a study of the data given in 

 the above Table. 



The breadth, thickness, and ratio of breadth to thickness for 

 the gills of the largest fruit-bodies of Coprinus atramentarius, 

 C. sterquilinus, and C. comatus that could be found are given in 

 the following Table. 



The Breadth and Thickness of the Gills of the Largest 

 Fruit-bodies of three Species of Coprinus. 



From the data given in the last column of the Table we may 

 conclude that, for very large gills, the ratio of breadth to thickness 

 for Coprinus atrarnentarius is about five times the ratio for C. ster- 

 quilinus and about four times the ratio for C. comatus ; and a 

 consideration of the data given in both the Tables teaches us that 

 the larger the fruit-bodies, the greater is the increase in the ratio 

 of gill-breadth to gill-thickness for C. atramentarius as compared with 

 C. sterquilinus and C. comatus. 



The fact that the gills of C. atrarnentarius are both thinner and 

 broader — and therefore from the mechanical point of view much 

 more delicate — than those of C. sterquilinus and C. comatus is, I am 

 convinced, directly correlated with the fact that in C. atramentarius 

 the gills are kept apart by the cystidial arrangement, whereas in 

 C. sterquilinus and C. comatus the gills are kept apart by the flange 

 arrangement. 



In what follows it must be borne in mind that the gills of Coprinus 

 atramentarius are exceedingly thin and yet exceedingly broad, for 

 only by a proper realisation of this fact can the mechanical function 

 of the cystidia be understood. 



When two gills of Coprinus atramentarius are torn apart, the 

 cystidia can be seen with the naked eye as tiny pellucid processes 



