CURREY, ON STEPHANOSPH HRA PLUVIALIS. 133 
this process will be better understood by reference to figs. 3, 
4, 5, 6, and 7, than by description. In passing from the 
state shown in fig. 3 to that shown im fig. 4, the outer mem- 
brane has gradually become invisible. Up to fig. 7 the pro- 
cess has occupied about two hours. The four daughter-cells 
(fig. 8) begin to quiver, and to endeavour to separate from 
one another. ‘Two cilia are now perceptible at the pointed 
extremity of each of the four cells (fig. 9), by the action of 
which the group begins to move as a whole, and in a laboured 
manner, in the water; ultimately, however, all trace of the 
enveloping membrane and of the glutinous connecting sub- 
stance disappears, and one by one the daughter-cells escape 
and become free. Figs. 10, 11, and 12 exhibit different 
forms of these free daughter-cells, which contain two, three, 
or several granules (amylon?) and sometimes also vacuoles. 
The sharp end is often prolonged into a colourless beak, as 
in fig. 12. At this period there is no proper cellulose mem- 
brane. At the moment of escaping their diameter never 
exceeds 0'010 m.m., but they soon enlarge and attain a 
diameter of 0:013 to 0°015 m.m. 
Their form and the length of the beak is variable, the 
latter being sometimes altogether wanting. In form and 
motion they resemble exactly the naked primordial cells, 
. which are produced by division from the resting-cells of 
Chlamydococcus pluvialis. The authors have never seen the 
resting-cells of Stephanosphera divide into more than four 
parts, but think it not improbable that division into a greater 
number (eight or possibly sixteen) sometimes occurs. 
The length of time which elapsed between the immersion 
of the dried resting-spores and the first appearance of the 
motile cells varied from nine to twenty-four hours. It was 
noticed that those resting-spores which did not produce 
zoospores within six days never did so afterwards, although 
they continued to live and were perfectly healthy. 
Zoospores, produced in the month of November, did not 
advance beyond the first stage. (Figs. 10, 11, and 12.) 
Others, however, produced in March, remained only a few 
hours in that condition, after which time a delicate membrane 
was formed round the body of the primordial cell; this mem- 
brane was at first closely attached to the primordial cell, but 
became gradually enlarged by absorption of water into a 
colourless enveloping vesicle (figs. 13 and 14), usually globular 
but sometimes oval, having two openings, through which the 
cilia penetrate. In this condition they attain a diameter of 
0-017—0:022 m.m., and are not distinguishable from encysted 
forms of Chlamydococcus pluvialis. Other zoospores, produced 
