CH.VIII.— MORPHOLOGY AND COURSE OF DEVELOPMENT.-—MYXOMYCETES. 423 
In the creeping movement the swarm-cell lies on the firm substratum, and 
either advances in one direction with a vermicular movement and. with the cilium 
stretched out in front; or it assumes a roundish form and thrusts out processes, 
pseudopodia, in every direction and then draws them in again. The two kinds of 
movement, the hopping and the creeping, often pass into one another, and may 
frequently be observed alternating with one another in the same individual with 
apparently alternating retraction and protrusion of the cilium. Swarm-cells with 
purely amoeboid motion have been unnecessarily distinguished by the name of 
myxamoebae. 
The swarm-cells multiply by bipartition, which, to judge by the vast numbers 
sometimes obtained from a sowing of the spores, may be repeated through several 
generations. The movement becomes more sluggish before division, the swarm-cell 
contracts into a spherical form and the cilium and the vacuoles disappear. This is 
followed by the appearance of an annular constriction in the middle which speedily 
becomes deeper and in a few 
minutes divides the body into two 
spherical halves which at once re- 
sume the characters of motile swarm- 
cells. The nucleus becomes indis- 
tinct during the division but does 
not entirely disappear, and it may 
be presumed from analogy that it 
also is divided. Exceptions to the 
rule here laid down have been ob- 
served in Chondrioderma difforme 
and Didymium praecox, in which 
the protoplasm was divided inside 
the spore-membrane and issued FIG. 183. Chondrioderma difforme. ı ripe spore. 2 the same ger- 
ae minating. 3—5 swarm-cells. 6, 7 the same in the amoeboid state. 8 two 
from it in the shape of two swarm- amoeboid swarm-cells in close contact. 9 the same when coalesced to 
. form the beginning of a plasmodium. 10 three swarm-cells in contact with 
cells, about as often as it escaped one another, 11 two of them after coalescence, the third still free. ı2 
from it in the form described above. Aner Cenkowski fom Sachs Lehrbuch Mage asstimes cn 
Famintzin and Woronin too found 
that the protoplasmic body which came out of the spore in the Ceratieae divided 
by successive bipartitions into eight portions, which separated from one another 
as swarm-cells provided with cilia. 
Section CXIX. The further development of the swarm-cells consists in their 
uniting together to form the large motile protoplasmic bodies, which Cienkowski 
named plasmodia. The course of events in this process was directly and completely 
observed under the microscope by Cienkowski in Didymium leucopus, Fr., 
Chondrioderma difforme (Didymium Libertianum) and Perichaena liceoides, Rost. 
(Licea pannorum, Cienk.). A number of less perfect observations of Lycogala, 
Fuligo and Stemonitis which have been communicated to me, and the resemblance to 
one another of all fully formed plasmodia, justify the assumption that the course of 
development is essentially alike in all Myxomycetes. 
The phenomena directly observed in the development of plasmodia are of the 
following kind (Fig. 183). In a few days after the spores are sown the divisions 

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