82 EVOLUTION OF PLANTS 
active movements and other evidences of life (Fig. 4, A). 
The Monera are aquatic, often parasitic, organisms and 
their life-history is a simple one. After the plasmo- 
dium has reached its maximum size it contracts and 
develops a firm covering and the contents of this cyst 
divide into a great many 
parts, each of which is pro- 
vided with a nucleus. These 
minute nucleated masses es- 
cape in the form of actively 
swimming bodies which may 
form a new plasmodium by 
simple growth; but some- 
times, by the fusion of a 
great number of the sepa- 
: rate spores, as in Protomyxa, 
DBE. ; a large plasmodium may be 
Fic. 4 (Mycetozoa).— A, a Slime- 
mould growing upon a bit of formed at once. 
Pane cee (one: In the Mycetozoa, or Slime- 
gia) of another form (Stem- moulds, which are often re- 
onitis) ; C, two ripe spores of 
Trichia; D, the active mo- garded as plants, the life- 
tile protoplasmic mass which 2 
escapes from the spore when cycle is somewhat more 
it germinates ; /, the flagellum i 
or motile organ; », the nu- complicated, due to the fact, 
cleus; E, two ameceboid later 
aes which bave lost the perhaps, that they are terres- 
agellum an ater unite i i . H 
with others to form the larger trial in their habits. The 
“‘plasmodium,” shown in A. active condition in these is 
v, the contractile vacuole. : 
also that of a plasmodium, 
these naked masses of white or yellow slimy matter 
often reaching a large size. The commonest of these 
is one found growing upon old tan-bark where the light- 
yellow soft mass may often be met with in damp, cloudy 
weather, the plasmodium shunning too strong lights 
