272 Mr. J.T. Arlidge on some of the Phases of Development 
itself a hollow in its wall (fig. 8). Moreover, the rotatory mo- 
tion became very slow and feeble, and although the external 
large cilia still flapped, bending towards the left, no motion oc- 
curred in that direction, save a shght oscillation of the lower 
half ; whilst the motion of the imner mass was irregular and 
slow. 
During the next quarter of an hour, the animalcule went on 
enlarging where occupied by the growing cells, the primary one, 
now spherical, protruding strongly : and, by reason of this cell 
having now nearly equalled in size the original being, the whole 
appear red like an animalcule in process of transverse fission (fig. 9). 
The second cell, which previously had occupied rather a lateral 
position with reference to the primary one, was now situated 
almost entirely beneath it. This second and smaller cell also 
was the only one which could be properly said to be meluded 
within the parent form, the larger one being but an appendage. 
The only portion which would seem to retain the latter in situ, 
was one—containing granular matter and some globules like the 
rest of the parent substance,—extending upwards for a short 
distance as a lateral band. 
The revolution of the animal seemed now to cease for a little 
while, but presently was resumed feebly and irregularly ; the ex- 
ternal cilia however only causing a jerking movement of the 
lower part. 
During the later changes, the cilia, which primarily fringed 
the entire margin, were now seen on the lower one—that viz. 
which remained of the original periphery—and also, owing to the 
transparency of the animal, along a line behind and just below 
that along which fission was about to occur (fig. 9). 
At seven o’clock, the lateral band attaching the budding cell 
to its parent had retracted to within a little distance of its base : 
the growth of the second cell had much advanced, and by its 
upward pressure against the primary sac, and the lateral pressure 
of the walls of the parent animal, it had assumed an irregular 
shape ; but its cavity remained quite diaphanous, excepting in its 
Jower part, where a few fine granules were dispersed (fig. 10). 
On one side of the two developing cells a small transparent 
elobule existed, along with three or four others, and some amor- 
phous particles, i in the substance of the parent bemg. ‘The cilia 
had apparently decreased in size—or at least in distinctness and 
energy, and at half-past seven they had disappeared, motion in 
them having previously been arrested (fig. 10). 
At about a quarter to eight o’clock p.m. the first-formed cell 
had rendered itsclf almost independent of its parent, and was 
bent to one side. The second sac had much increased in size 
(fig. 11). 
Having withdrawn my attention for a moment to complete the 
