Notes on some Microscopic Organisms. 27 
fiation goes on by means of which a very delicate investing mem- 
brane is formed, but it is so delicate that it can only with difficulty 
be seen, and in fact can hardly be said to exist as a separate mem- 
brane. But upon one side is now seen to appear a bulging out- 
wards of the mass until a nipple-like protuberance is formed, which 
however is not filled with the green matter formed elsewhere, but 
is clear and colourless. I have noticed that in most cases this pro- 
truding portion is formed at the point just opposite to the place in 
the cellulose cell-wall of the filament from which the spherical body 
has just escaped. But as this is not invariably the case it can 
hardly be considered as anything more than accidental. Soon 
thereafter there is seen to be a slight agitation going on upon the 
surface of the sphere, near to, and upon one side of the clear space. 
This movement then assumes a more definite character, and at last 
a moving cilia is seen to be formed or differentiated from the outer- 
most portion of the globe. Soon another and another are formed 
in the same manner, attached by their bases around the clear 
space, and soon, that is to say in fifteen or twenty minutes, a ring 
of active cilia; is seen to surround the nipple-like projection. As 
soon as they have all made their appearance, immediately they all 
begin to move together and in a violent manner, so that motion is 
imparted to the whole mass, and it swims about actively through 
the water. And this motion is so active that it is often difficult to 
follow the mass, and to keep it within the field of the microscope. 
For several minutes, or more rarely, for half an hour, this motion 
goes on, and up to this point I find that these changes have been 
observed and recorded by others. But now comes what I consider 
the most important part of this history. 
It can be readily understood that, on account of its violent 
action, the further history of the spherical mass could not easily be 
followed, but fortunately on several occasions I saw specimens 
entangled in a mass of filaments in such a way that they could not 
escape from the field of view. Then I saw that the motion became 
gradually less and less vigorous, and at the same time the ciliae 
disappeared one by one, melting out of view, being apparently 
absorbed again into the mass from which they were originally 
developed. At the same time one of them seems to elongate until 
it is one to three times as long as the diameter of the spherical 
mass, and also its point of attachment changes until we find it 
springing from the centre of the clear projection. While this is 
going on, the whole mass, not changing its position, assumes, how- 
ever, a totally different outline. That is to say, the clear nipple- 
like blunt part remains about the same, but the opposite portion 
becomes pointed, while the intermediate space is inflate in such a 
way that the whole creature in outline somewhat resembles a tre- 
foil clover. The inflated part, however, does not remain rigid, but 
