No. 2.] SPINNING ACTIVITIES OF PROTOPLASM. 379 
motions. These become stronger, more rhythmic and or- 
ganized in action, and soon form a sufficiently harmoni- 
ous impulse to carry about the blastula as a free-swimming 
organism. 
After invagination, those cells which as entoderm project, 
first as a plug and later as a tube, into the cleavage cavity, 
spun strongly and in a free protoplastic manner from their 
portions facing the cavity, which, like the same region of the 
ectoderm cells, were more fluid in appearance. These ento- 
derm spinnings crossed the cavity to the ectoderm cells and 
in their course freely anastomosed in many places with the 
spinnings of the latter. 
After the mesenchyme cells were added to the group of 
internal cells, these, by spinning in even more free and pro- 
fusely protoplastic a manner, increased very greatly the number 
of intercellular connections. 
It now became difficult to distinguish the various groups of 
spinnings from each other; in the majority of cases where 
anastomosis had taken place, it was impossible, because new 
centres of spinning were formed of accumulated substance 
which might have come from anywhere. The network was also 
most unstable from moment to moment. Yet there were 
many tapering processes which could be connected with their 
point of origin. 
Larval stages were followed up to quite late periods, even to 
time of formation of the proctodzum; and the internal spinnings 
seemed at no time to pause or cease. 
It should be pointed out that in the early stages of the seg- 
menting egg the protoplasm which spins is not the least, but 
the most, highly organized portion of the cytoplasm. It is also 
the most viscous portion, as can readily be demonstrated by 
physical experiment. 
Polar Globules. — Perhaps even more strange than these 
spinnings from the egg were similar activities shown by the 
cytoplasmic envelope of the chromatin granules of the polar 
globules. 
During that short period of quiescence for the egg pellicle, 
which was spoken of above as following the extrusion of the 
