No. I.] REGENERATIVE ENERGY. at 
Although it is by no means certain that the hyaline protoplasm 
of these rings is not in part derived from the germinal vesi- 
cle, it is quite clear that the phenomena are very different 
from the polar phenomena attending the division of the first 
cleavage-nucleus. These remarkable exhibitions of polarity in 
the cytoplasm appear early in the pronuclear stage, and con- 
tinue not only during the centripetal march of the pronuclei but 
even after the first cleavage-nucleus has entered upon its 
kinetic phases of division. Thus we have two distinct series of 
polar phenomena in progress at the same time, one displaying 
ttself in the cytoplasm, the other in the nucleus. We cannot 
suppose that the cytokinetic series is dependent upon the karyo- 
kinetic series for two reasons: first, because the former begins 
earlier than the latter ; and second, because such cytokinetic dis- 
plays are unknown in other eggs. The second ground would 
also hold against referring them to pronuclear influences. AI- 
lowing that it may yet be possible to demonstrate that these move- 
ments originate in response to pronuclear influence, it would 
still be very difficult to believe that they are sustained through- 
out by the continuous action of the same agency. It would be 
altogether more probable, as a little reflection will show, that 
the movements once started are capable of maintaining them- 
selves, independently of the inciting cause.* 
Cytokinetic Phenomena. — The cytoplasm exhibits a great vari- 
ety of changes and conditions, variously described as ‘polar 
concentration,’ ‘radiating bands,’ ‘ waves of contraction,’ ‘zonal 
constrictions,’ ‘automatic cortical layer,’ ‘amoeboid movements,’ 
‘phases of segregation,’ ‘astral radiations,’ ‘rhythmic contrac- 
tility,’ ‘migratory movements,’ ‘crown of folds’ (Faltenkranz), 
‘autonomic movements’ (rotation, circulation, pulsation), etc. 
While some of these phenomena might, with considerable 
reason, be claimed as purely cytokinetic, most of them are so 
intimately associated with karyokinetic activity that they must 
be explained, either as the direct result of the latter, or as the 
effect of impulses generated by the interaction of nucleus and 
* The polar and parapolar circles described by Van Beneden (No. g) in the egg of 
Ascaris, are not comparable with the polar rings of Clepsine. For the ‘ disque 
polaire’ arises before, and disappears with, the penetration of the spermatozoon; 
the polar rings (Clepsine), on the contrary, appear after the penetration of the 
spermatozoon, and are not wholly dissipated until after the completion of the first 
cleavage. 
