156 
SYDNEY .1. H[CFvSON AND .T. T. WADS^YOln'H. 
division we have been able to follow is the formation of 
the me^anucleus or megannclei of the geramalge. Before 
the outline of a young geinmula is seen in the cytoplasm, one 
or more knob-like outgrowths are formed from the ribbon-like 
meganucleus of an arm or of a part of the stolon. These grow, 
and as the outline of the geramula is developed become con- 
stricted at the base, and ultimately the knob or knobs are 
separated off. The granules in the constricted part of the 
outgrowth become elongated, spindle-, or rod-shaped (fig. 20) 
dnring the constriction, but regain their spherical form as 
soon as the Tueganuclei of the gemmnlge are free. No distinc- 
tion whatever can be drawn between the minute structure of 
the meganncleus where it is g-iving off these branches and that 
of other regions — in other words this division is purely 
amitotic. But it is not only amitotic, it is obviously unequal. 
In the amitotic division of the meganucleus of many Ciliata 
and of some Acinetaria (e. g. Dendrocometes) the division 
may be an equal division, the two products of fission in the 
former case, and the parent and geminula in the latter may 
receive an equal portion of the parent meganuclear substance. 
In the case of Dendrosoma it is obvions that the gemmula 
receives only a small part of the total meganuclear substance 
of the parent. The meganucleus not only divides in gemmula 
formation but occasionally in ordinary vegetative growth, 
as is shown by the fact that the meganuclear bands are 
sometimes discontinuons. We have no reason to believe 
that this division is brought about by any other process than 
simple constriction. 
The fragmented or disintegrated condition of the mega- 
nucleus may be seen in many preparations. It is by no 
means confined to the parts of the meganucleus in the stolon, 
but mav occur in the basal portions of the arms. In some 
cases scattered chromatin granules (fig. 12) may be seen in 
the cytoplasm in regions where a distinct but not well- 
defined meganuclear band occurs, but in other regions the 
whole of the meganuclear structure appears to be scattered 
in the cytoplasm (fig. 13). If it is a fact that the mega- 
