slow and variable circulation-current in the parenchyma of 
the solid plasma-body and its pseudopods, and visib'v also 
on their surfaces. It is exactly as in the Acanthometra, its 
course is constantly changing. Ramification, anastomosis, 
and flattening-out of the rigid pseudopods is rare. In long- 
fasting individuals the quantity of sarcode-granules is con- 
siderably decreased. At last they seem to vanish entirely. 
The Myxastrum increased by artificial division, like Proto- 
myxa. In two individuals, one of which I had torn in two 
pieces and the other in three (under the dissecting micro- 
scope), each piece slowly rounded itself into an independent 
viscid ball, which gradually began to stretch out its retracted 
pseudopods again, and then took nourishment itself like the 
undivided individuals. 1 have already described a similar 
artificial divisibility in the allied Actinosphcerium Eichhornii 
(in 1862). 
The active movements of the whole body were as weak and 
slow in Myxastrum as in Actinosphaerium ; but it was able to 
move itself on the stage very slowly and unsteadily, appa- 
rently rotating or rolling, or pushing itself along on the 
spine-like pseudopods like a sea-urchin. The fortunate re- 
sult that my researches in the life-history of Protomyxa had 
had, permitted me to hope to observe a similarly complete 
development-cycle in Myxastrum also. I isolated several of 
the largest and best-fed Myxastri in separate watch-glasses 
with sea-water. I kept these in a spacious damp room for 
several weeks, "without the Myxastri dying. 
During the first few days the isolated Myxastri showed no 
alteration. But then I observed first in one, and then in a 
second individual, that the viscous little star had retracted 
its ra\s, and contracted itself into a perfectly simple viscous 
ball with a smooth surface. All remainsof the previously 
taken nourishment were removed, and no traces of any 
objects could be observed in the entirely homogeneous sar- 
code body, except the numerous fine granules. A few days 
later a double sharp contour, instead of the former single 
one, became visible, and now it appeared that the Myxas- 
trum had encysted itself like the Protomyxa. The cyst- 
membrane, at first very thin, became slowly thicker and 
thicker, new concentric layers were separated in it, and, 
finally, its thickness reached an eighth of the diameter of the 
enclosed plasma-ball (fig. 13). 
The encysted Myxastrum, as well as the encysted Pro- 
tomyxa, resembled a perfectly simple globular Lepocytode, 
a perfectly structureless and homogeneous plasma-ball of 
•008 mm. diameter. Chemically, too, it showed the same 
