3 o RESEARCHES ON FUNGI 



tubes, or spines in any fruit-body, be represented by the con- 

 traction Sp. Inc. 



Then Sp. Inc. = |- 



The value of the specific increase has been measured in a few instances. 



For species of Agaricinete the number of gills was counted and 

 the gill-systems studied. The number of gills of each size was 

 determined. A few gills of each size were dissected off the fruit- 

 body, placed on paper, and drawn. The paper drawings were then 

 cut out with scissors, and their area determined by weighing them 

 against squares of paper marked out in square millimetres. The 

 fact that each gill has two sides was taken into account. With the 

 data thus obtained the total area of the gills could be calculated. 

 The value of A w T as calculated from measurements of the diameters 

 of the pileus and of the stipe. 



Full-grown specimens yielded the following results : — 



As an illustration of the method of calculating specific increase, 

 details for the specimen of Triclcoloma personatum will be given. 



Diameter of pileus = 127 mm. 

 Diameter of stipe = 28 „ 



Hence, the area of the underside of the pileus, with the gills 

 removed, exclusive of the part occupied by the stipe, =12G72'S 

 -G16 mm. 2 , or A =120-1 cm. 2 . 



Number of primary gills = 101 



„ ,, secondary ,, = 10] 



,, „ tertiary „ = 202 



„ ,, quaternary ,, = 404 approximately. 



