2IO MYXOMYCETES. 



dons, a capillitium. Lime, another animal character, which is 

 present in the plasmodium, remains in the capillitium and 

 peridium as calcareous nodes. 



The species of this group are all interesting. They are 

 nearly all small and easily overlooked. Most of the didymium 

 are not much larger than a pin's head. 



There are quite a number of good genera included under this 

 group. My list represents only a few of the many, viz : 



Craterium. — Opening with a lid. 



Physarum. — Sporangium simple. 



DiACH/EA. — Capillitium a network of violet threads. 



FuLiGO. — ^thalium not clustered, yellow and brown. 



Stemonitis. — Capillitium forming a network on the walls 

 of the sporangium. 



DiCTYDiUM. — With parallel ribs. 



Didymium. — Lime in crystal form on sporangium. 



Lycogala. — ^thalium with a bark of colored cells. 



Lachnobolus. — Capillitium grown to the walls of the 

 sporangium. 



Arcyria. — Capillitium free from the walls of the sporan- 

 gium. 



Trichia. — Threads of the capillitium simple. 



Hemiarcyria. — Threads of the capillitium more or less 

 jointed into a net. 



Genus L CRAT]^RIUM. 



Sporangium simple, rigid, closed on top with an operculum, 



C. leucocephalum. Pk. 



Sporangium, more or less pyriform, stipitate, square sided, 

 operculum thin. 



Found in a lawn near Trexlertown, Pa., on a blade of grass. 



