14 A Monograph of the Myxogastres. 



distinctions depending more especially on the mode of branching 

 and colour. The point of interest in the present connection is the 

 mode of spore formation. Without entering into details, the proto- 

 plasm, immediately preceding spore formation, becomes arranged 

 on the branches as a peripheral layer of cells enclosed in cell- 

 walls, which, in the case of Ceratium hydnoides, give a cellulose 

 reaction when young. Owing to local growth, the central por- 

 tion of the free side of each cell grows outwards in the form of a 

 slender elongated cylinder until it measures about 10 /tx in 

 length by about 3 jx in diameter ; the next change consists 

 in the expansion of the free end of this outgrowth which con- 

 tinues until it assumes in C. hydnoides, a broadly elliptical form, 

 about 10x6 7 /* in size; into this swollen apical portion the 

 whole of the protoplasm then passes through the stalk from the 

 parent cell, after which a transverse septum is formed in the 

 stalk-like portion close up to its swollen apex, which eventually 

 breaks away at the septum as a mature spore. In C. hydnoides 

 the stalks persist after the spores have fallen away, each closed 

 at the apex by the septum which formed the line of dehiscence, 

 and the homology with the formation of conidia or spores in the 

 Basidiomycetes is perfect. In each case we find a cell richly 

 supplied with protoplasm giving origin by local growth to one or 

 more thin spine-like processes, each of which becomes much 

 enlarged at its apex ; into these enlarged portions all the proto- 

 plasm from the mother-cell becomes concentrated and retained 

 by the formation of a septum across the stalk close to the 

 swollen apex, which eventually falls away at the septum as a 

 ripe spore. The first appearance of a transverse septum being 

 for the purpose of isolating a mass of protoplasm concentrated 

 for purposes directly concerned with reproduction suggests the 

 idea, if nothing more, that the Myxogastres are in touch with 

 other acknowledged members of the vegetable kingdom. The 

 remaining species of Ceratium show the same mode of spore 

 formation, but in C. arbuscula, B. and Br., a very fine much- 

 branched species, the thin outgrowth bearing the spore at its 

 apex is much larger than in C. hydnoides, and the transverse 

 septum is even more distinct, while in C.filiforme, B. and Br., the 



