404 



MYCETOZOA 



Resting states may occur at all motile stages of the life-history. Micro- 

 cysts are the resting states of swarm-spores. They round themselves off, 

 and are invested with a delicate membrane or only with a firm border. 

 Young plasmodes similarly form thicker-walled cysts, and mature plas- 

 modes form multicellular bodies sderotes. 



The spores of Myxomycetes are formed either endogenously within 

 sporanges, or on the free surface of sporophores (Ceratieae). Sporanges 

 are formed either by the whole plasmode becoming one, or the plasmode 

 divides into portions, each of which becomes a sporange. Such as are 

 situated on stalks begin as small swellings on a strand of the plasmode, 

 and by degrees acquire their mature form as the protoplasm ascends into 



FIG. 335. a, Ccratinm hydnoidcs Alb. and Sch. Piece of sporophore in act of forming. 

 b, Ceratiiim porioides Alb. and Sch. Piece of the margin of a sporophore ; spore- 

 formation beginning; two spores which subsequently become slightly ellipsoid on their 

 stalks, (a x about 68, b x 120.) (After Famintzin and Woronin.) 



them. While this process of formation goes on the solid contents of the 

 plasmode are expelled. The interior of the mature sporange is either filled 

 with spores only, or more commonly there is also present a capillitium 

 consisting of numerous filaments traversing the cavity in all directions. 

 They probably serve as supports to the wall of the sporange in the first 

 instance, and may further be connected with its rupture and the dispersal 

 of the spores. 



There are only two known species of Ceratium (Link), a genus 

 which forms free spores, i.e. not within a sporange. In this case the* 

 plasmode before spore-formation consists of a network of innumerable 

 branches from which cylindrical processes arise. The whole protoplasm 



