THE MYCETOZOA 149 



such as a Petri dish and a small flake of sclerotium placed 

 on the fungus will in a day or two produce a plasmodium, 

 which in the course of a week in warm weather will cover 

 the greater part of the Stereum. 



A square of glass should be placed over the culture in 

 such a way that a very small air- way is left at each side. 



At a point near the middle of the glass the Stereum may 

 be brought into contact with it ; when hungry the mycelium 

 will spread widely over the glass. Now, if fresh Stereum is 

 added to that in the dish, the plasmodium will leave the 

 glass to form a dense layer over the fresh food. 



When the plasmodium is spread on the glass this may 

 be raised a little above the edge of the dish by placing a rod 

 under the glass at each side ; this measure will allow the 

 plasmodium to dry slowly. As it dries it shrinks to form a 

 sclerotium. After a day's gradual drying the glass may be 

 removed and the sclerotium dried completely. It can then 

 be scraped from the glass in flakes like shellac and kept dry 

 for future use. 



Sporangia. There is a wide range of form in the sporangia 

 of some species : thus in Physarum nutans and Didymium 

 squamulosum stalked and sessile sporangia and vein-like 

 plasmodiocarps are often formed from the same plasmodium. 



The elements of which Fig. 42 is made up are parts 

 chosen from seventy-seven double plates in the first edition 

 of A. Lister's book. The plates are collotype reproductions 

 of water-colour camera drawings. The small portions here 



