THE MYXOMYCETES OF PICTOU COUNTY, — MOORE. 177 



Myxogastres witili the limits originally assigned it — that is, as 

 co-extensive with the Endosporece of Rostafinski's classification 

 and narrower than tiie Myxogastercs of Schroter which is a 

 synonym of Eostafinski's Mycetozoa. 



Lister, on the other hand, accepts the group Mycetozoa as 

 established by Rostafinski, but excludes Dictyostelium, one of 

 the Acrasiece, which had been admitted by the latter evidently 

 through a misapprehension of the nature of its plasmodium. 

 '' We have thus,'' he says, " a clearly defined group of organ- 

 isms separated from all others by the following combination of 

 characters. A spore provided with a spore wall produces on 

 germination an amoeboid swann cell which soon acquires a 

 flagellum. The swarm cells multiply by division and subse^ 

 quently coalesce to fonn a plasmodiimi which exhibits a rvthmic 

 streaming. The plasmodium gives rise to fruits which consist 

 of supporting structures and spores. In the Endosporece these 

 have the form of sporangia each having a w^all within which the 

 free spores are develi:)ped. A capillitium or system of threads, 

 forming a scaffolding among the spores is present in most 

 genera. In the Exosporece the fruits consist of sporophores 

 bearing numerous spores on their surface." (A monograph of 

 the Mycetozoa, p. 2.) 



Macbride in his Xorth American Slime Moulds (1899), 

 uses the term " Myomycetes (Link) de Bary," as a general 

 title, but includes in the group such fonns as Plasmodiophora 

 v.'hicli, as has been said, were excluded by de Bary in his treat- 

 ment of the group as being of dcubtful affinity. As thus limited, 

 the group embraces the Phytnmyxin?p and Myxogasteres of 

 Schroeter's system. 



. Macbi'ide groups the Myxomycetes as thus defined into three 

 raain divisions or sub-classes: 



A. Parasitic in the cells of living plants. 



Snl)-clas?. Phytomyxinae. 



