DUBLIN UNIVEESITY ZOOLOGICAL AND BOTANICAL ASSOCIATION. 245 
this clear space several active granules may be seen in constant agitation, 
like those in Closterium, Docidium, &c., though there does not appear 
any special chamber, as it were hollowed out of the endochrome, .con¬ 
taining the moving granules, as in those genera. These were more nume¬ 
rous and more evident in the fresh specimens some five or six months 
ago, when I first noticed this plant, than they are in specimens gathered 
during the winter. Of these active granules I have remarked sometimes 
one or two in some specimens notably larger than the others, and I have 
noticed the granules continue their active motion in the water for some 
time after being set free by the forcible fracture of the cell, as will pre¬ 
sently be again alluded to. If the joint under examination be now caused 
to make a quarter of a revolution on its long axis, the narrow or side 
view of the compressed endochrome becomes turned towards the observer, 
and consequently presents a different aspect (see Tig. 2). The outline 
of the endochrome, now brought to view, is seen to be somewhat un- 
dulatory or waved, owing to the mass of endochrome closely embracing 
the central row of light-coloured corpuscles which are still distinctly 
visible, so that at the regular intervals of their occurrence they form 
slight protuberances or distentions of the compressed band of endochrome, 
which at this edge view does not fill more than about a third of the 
diameter of the cell. I have sometimes noticed (but rarely, however) 
each half of the endochrome to be turned a different way with regard 
to the other, or at right angles, that is, one half presenting the broad 
view simultaneously with the other showing the waved, compressed, 
lateral view, which conditions were of course reversed on the joint being 
caused to turn longitudinally one quarter of a revolution. I have once 
noticed one half of the band of endochrome to be, as it were, twisted upon 
itself. The transparent pale space, due to the suspension of the endo¬ 
chrome, is again manifest at this edge or lateral point of view, when it is 
also seen that each half of the endochrome does not approach the other 
directly straight, but, at a short distance from the central clear space, 
they are each somewhat suddenly curved towards each other, and towards 
the boundary wall, to which they approximate closely at the same side. 
I have only once or twice seen the base of each half of the endochrome 
curved towards the cell-wall at opposite sides. Of course the transparent 
space at each end of the endochrome, bounded by the primordial utricle, 
is equally apparent in the present view as it was before, and the active 
granules can be equally well seen exerting their curious motion ; and in 
addition, owing to the compressed and narrow mass of cell-contents 
leaving a considerable space, they can not unfrequently be seen at a 
distance from the end of the joint swimming up and down with a tre¬ 
mulous, agitated, fluttering, uncertain motion. Occasionally one can 
be seen, having travelled up the length of the joint, to escape into the 
terminal space and join in the active dance of the other granules. Even 
at the view of the joint, first adverted to (Tig. 1), which exposes the 
broader diameter of the band of endochrome, and which leaves no room 
for them at the side between it and the outer wall, these wandering gra¬ 
nules can, with certain illumination, be seen like darkish specks moving 
VOL. V.-PEOC. SOC. 2 K 
