194 Transactions of the Royal Microscopical Society. 
finding instances of the phenomenon. But if the amoeboid forms 
be patiently watched here and there over two or three days of 
watching, some of those which we have described as in a self- 
kneading process internally will be seen to retain the form of the 
flagellate end more perfectly than others, while the opposite end of 
the sarcode will become much more truly amoeboid. Now if this be 
carefully watched, the “ ventral disk ” (as we have called it for work- 
ing purposes), or nuclear body, will be seen to grow unusually large 
and prominent. The “ eye spots ” will be seen to be in rapid rhyth- 
mical action, and soon — in the course of two or three hours — the 
posterior end of the sarcode will be strongly amoeba-like, pseudo- 
podia being protruded with a more constant and rapid motion than 
is usually seen in the amoeba. A “ calycine ” in this condition is 
drawn at Fig. 11 , and another very near the same field at the same 
time is seen at Fig. 12. It will be seen that the flagellate end of 
both is only slightly changed, and the large size of the nucleus- 
like body will be observed. Now in this condition they swim 
more and more slowly for some hours, until in some cases they 
cease to swim entirely, moving exactly as the amoeba does, by the 
extrusion of pseudopodia. Indeed it could not be distinguished 
from an amoeba but for the persistence of the shape of the flagellate 
end of the body and the slow waving of the flagella. Its aspect in 
this condition is drawn at Fig. 13. And one remarkable peculiarity 
of this condition is the great voracity of the creature. The “ field” 
in its neighbourhood is rapidly cleared of dead and living bacteria, 
simply devoured by it. It is probable that this capacity for absorb- 
ing nutriment, which must give large advantage in the struggle for 
existence, explains the amoeboid condition so common at what will 
be seen to be such an important period in the development of the 
monads. 
In some instances it does not become so utterly amoeba-like as 
this, but swims very slowly ; but in either case, whether by swim- 
ming or creeping, if it meet another in a similar state the amoeboid 
parts touch, and instantly blend into each other. This is shown in 
Fig. 14. In this condition the blended creatures may swim again 
with great freedom and ease, both sets of flagella acting apparently 
in concert. But now blending of the entire mass goes on, and in 
the course of thirteen hours the two “ eye-spots ” blend and cease 
to act ; the two sets of flagella unite and fuse into mere sarcode, 
and the two nucleus-like masses, a, b, flow into one, until in about 
eighteen hours all trace of form is gone, and a somewhat irregular, 
distended sac is all that remains. This is drawn at Fig. 15 ; and 
in the course of another six hours this sac becomes round, and will 
be seen, if carefully watched, to pour out in all directions, without 
any violent splitting or breaking up, innumerable masses of little 
bodies, just visible to a magnifying power of 1800 diameters, and 
