Dr. A. de Bary on the Mycetozoa. 237 



tures met with in the ripe Gasteromycetes are explicable as pro- 

 ducts of the development of true basidiospores. 



The sporotheca3 of the Mycetozoa present to the naked eye a 

 close resemblance to the ripe peridia of the Gasteromycetse ; and 

 the similarity between the two groups is rendered greater by the 

 circumstance that their habits are alike, and that they are both 

 particularly common in decomposing vegetable infusions. In- 

 deed they are only satisfactorily distinguishable on a comparison 

 of their early development. 



The author's next task is to minutely examine the structure 

 of the genera of Mycetozoa or Myxogastres, among which are, 

 Physarwn, Didymium, Diderma, ^Ethalium, Spumaria, Stemo- 

 nitis, Diachcea, Licea, Arcyria, Trichia, and Lycogala. 



The earlier stages of development of the Mycetozoa which 

 result in the formation of the sporothecaB, externally so like those 

 of the Fungi, have hitherto been very partially investigated. 

 The youngest condition recognized was in the form of a mucor 

 or mould, interspersed with countless specks, which either con- 

 stituted a formless, often thick, film on the substratum, or took 

 the definite figure of pediculate drops, or formed a network of 

 anastomosing veins over its surface (fig. 18). The mucor is 

 usually white or yellow, seldom of any other colour. A peculiar 

 kind of sporothecse was often seen to form, under the eye of 

 the observer, with astonishing rapidity, gradually hardening, and 

 assuming the structure, consistence, and colour of such organs. 



De Bary has more minutely examined these phenomena, at first 

 in jEthalium septicum, and subsequently in other species. On de- 

 taching a portion of the surface of Mthalium where fructification 

 is proceeding, it is found to consist superficially of a shining yel- 

 low substance of a mucoid consistence, tremulous, and reduced 

 by slight pressure to a homogeneous pulp. Yet, when intact, it 

 is not formless. Its surface is then seen to be overspread with 

 a multitude of obtuse processes or papillae, grouped in bunches, 

 either erect or twisted together, and which seem to coalesce by 

 their bases in the subjacent mass. The whole bears a general 

 resemblance to a stem of coral, or to a piece of Clavaria flava 

 (fig. 18). 



On immersing a portion of this yellow mucor in alcohol, it 

 becomes so hardened that it may be cut into thin sections, when 

 its substance can be shown to be a tissue composed of interlacing 

 cords or fibres (fig. 16), which terminate on the surface by free 

 extremities, and there constitute the ramose lappets and papilla 

 above described. This same structure may be detected in Mtha- 

 /mm-fronds a foot in circumference, and where the fructifying 

 portion is as much as two inches in depth. In such the same 

 yellow cords or fibres are found, with the like consistence ; and 



