SLIME FUNGI— MYXOMYCETES 305 



are sharply defined and distinct. It is in the vegetative stage 

 that all the supposed affinities with the animal world are 

 encountered, and in the reproductive everything is suggestive 

 of Fungi, even to the terminology which is borrowed from, and 

 represents identical structure with what is familiar in Gas- 

 tromycetes. The outer wall is either a sporangium or peridium, 

 the threads of the interior still compose a capillitium, the con- 

 tinuation of the stem into the interior is a columella, and the 

 reproductive units are not ova, but the spores. This is accounted 

 for by De Bary from the " close agreement in structure and in 

 biological characters between their organs of reproduction and 

 the spores of Fungi." As Mr. Massee has lately pointed out, 

 it is clear that De Bary derived all his reasons and his evidence 

 against the vegetable nature of the Myxomycetes from the early, 

 or vegetative, phase. On the other hand, it seems to have been 

 suggested that in the later, or reproductive, phase the disparity is 

 so great between the structure and biological characters of the 

 Mycetozoa and those of any of the lower animals, that he was 

 compelled to use the terms, in describing them, which belong 

 also to the Gastromycetes. Here, then, we are supposed to 

 come face to face with a problem — certain organisms in their 

 early, or vegetative, stage belonging to the animal kingdom, and 

 subsequently in their final, or reproductive, stage undoubtedly 

 vegetable, — a worse example of a dual-hypothesis than that 

 which combines an Alga with a Fungus to produce a Lichen. 



Taking away all expletives, and reducing the indictment 

 to its simplest form, it remains as a specific reason that " the 

 characteristic mark of separation lies in the formation of Plas- 

 modia, or aggregation of swarm-cells." In his recent monograph 

 of this group,^ Mr. Massee has faced and combated the position 

 occupied by De Bary, step by step. " In the Myxomycetes," 

 he says, " the spores on germination give origin to one, two, or 

 more naked cells, which possess the power of movement, due 

 to the protrusion of pseudopodia, or the presence of a cilium ; 

 these cells are known as swarm-cells. The swarm-cells possess 

 a nucleus, multiply by bi-partition, and eventually coalesce to 

 form a plasmodium in the following manner. After the pro- 

 duction of numerous swarm-spores by repeated bi-partition, little 



^ Massee, Monograph of the Myxogastres, London (1892), p. 5. 

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