PREFACE xiii 



onym for Gasteromycetes Fries. In 1858 De Bary applied the 

 title Mycetozoa to a group which included the then lately dis- 

 covered Acrasiece with the true Slime-moulds, both endosporous 

 and exosporous. For all except the Acrasiece De Bary retained 

 the old appellation, Myxomycetes. Rostafinski adopted De 

 Bary's general name, but changed its application. As it has 

 been shown, since De Bary's time, that the Acrasiece have no 

 true plasmodium, and are therefore not properly, or at least 

 necessarily, associated with the Slime-moulds, there appears no 

 necessity for the term Mycetozoa, and the question lies between 

 Myxogastres and Myxomycetes. Of these two names the 

 former, as we have seen, has undoubted priority, but only as 

 applied to the endosporous species. The same thing was true 

 of Link's designation until De Bary redefined it ; but having 

 been taken up by De Bary, redefined, and correctly applied, 

 MYXOMYCETES (Link) De Bary must remain the undisputed 

 title for all true Slime-moulds, endosporous and exosporous 

 alike. 



In arranging the larger divisions of the group the scheme of 

 Rostafinski has been somewhat modified in order to give expres- 

 sion to what the present author deems a more natural sequence 

 of species. The highest expression of Myxomycetan fructifica- 

 tion is doubtless the isolated sporangium with its capillitium. 

 This is reached by successive differentiations from the simple 

 plasmodium. The sethalium may be esteemed in some instances 

 a case of degeneration, in others of arrested development. In 

 any event, in the present arrangement, sethalioid forms are first 

 disposed of, leaving the sporangiate species to follow from 

 plasmodiocarpous as directly as may be. 



The artificial keys herewith presented proceed on the same 

 plan, and are to be taken, as such keys always are, not as 

 definitive in any case, but simply as an aid to help the student 

 more speedily to reach a probable satisfactory description. 



For collections of materials representing various localities 

 and for various assistance, the author would express obliga- 

 tions to Mr. P. Bartsch, Washington, D. C. ; Mr. H. C. 



