26 
Henfrey, on ChlorosphcBra. 
of the green contents. At a certain epoch a faint equatorial 
line is perceptible running across the cell, and after this a 
shallow equatorial groove becomes perceptible by its exhibit- 
ing a triangular light space at each end of the equatorial 
line (fig. 2). At this time none of the internal changes can 
be distinguished, as the dark-coloured contents completely 
fiU the cell, and render it turgid. If the cells are now very 
gently pressed by the covering glass (fig. 3), the walls give 
way with elasticity, and two new cells slip out from the 
parent sac (fig. 5). By careful management, and by exa- 
mination of the empty parent- cells, we find that the parent- 
cell has first become divided by a septum into two equal 
chambers (fig. 4), the septum being double, and continuous 
with a layer lining the primary wall as usual. As the new 
cells possess an extremely thin membrane as soon as we can 
examine them after they escape, we may suppose that they 
acquire a membrane inside the parent-cell, produced by 
their own protoplastic layer [primordial utricle). We have 
said that the dehiscence of the parent-cell takes place with 
elasticity. Pressure causes the parent-cell first to bulge on 
each side (fig. 4), then the septum splits a little way down 
into two lamellae on one side, and next a fissure takes place 
partly or quite half round each chamber at the equatorial 
line, allowing the new cell to slip suddenly out. The new 
cells immediately expand from the hemispherical into the 
spherical form, and are then found somewhat smaller than 
the full-grown parents. From appearances met with at 
various times, it seems probable that the two halves of the 
parent-cell sometimes separate entirely before they discharge 
their progeny (fig. 10) ; or the same appearance may, 
perhaps, be explained, by supposing that one or both of the 
new cells are unable to extricate themselves from the parent- 
cell, the two halves of which separate during decay, by 
gradual solution of their wall from without inwards. 
In one case Mr. Oliver observed an appearance like the 
swarming of very minute granular bodies in the interior of 
a chamber of a parent-ceU, from which a new cell had just 
escaped. The explanation of this is at present obscure; 
but if the bodies hereafter described are really antheridia, 
the granular corpuscles may have been spermatozoids. Mr. 
Oliver, in some cases, found a division of the parent into 
four new cells, but this appears to be unusual as regards the 
vegetative multiplication. 
The new cells have an extremely delicate membrane when 
just born,'' as may be shown by bursting them by pressure 
(fig. 6). Of the cells formed in this way the subsequent 
