28 
Notes on some Microscopic Organisms. 
soon subsides, while the clear end becomes more pointed, and now 
the creature is spindle-shaped in outline. As there is now hut one 
cilium, it is by means of it that the creature moves about in an 
extremely active manner. In some, and in fact in by far the most 
cases I observed, the swelling of the middle portion is not fixed, 
but moves down the length of the creature towards what may with 
some propriety be termed the posterior extremity, as it is always 
projected backwards when it is moving through the water, and 
there disappears, to be soon followed by another swelling and wave- 
like projection, and so on. In fact, an action resembling very 
closely that seen to take place in the intestines of animals, and 
known as peristalsis, takes place. Many individuals move directly 
and straight onwards, preserving their body perfectly rigid, so 
that after a time the cell-contents are seen to arrange themselves in 
longitudinal bands. Others, again, revolve on their longest axes, 
and soon the cell-centents of these are seen to have arranged them- 
selves in spiral lines corresponding to this movement. Some of 
these retain their straight condition, while others become bent 
around so as to form almost a complete circle, and then proceed 
onwards by a rolling motion. There is a regular and determined 
passage from one of these states to the other, as I was able to 
ascertain by careful watching ; but the most remarkable fact con- 
nected with the whole matter is, that all of these forms are pre- 
cisely similar to creatures which have been ranked by Ehrenberg 
and others in the animal kingdom, under different names, but most 
commonly that of Eaglena. To make the resemblance of the 
Euglenas still more marked, as soon as the circlet of ciliae has 
disappeared, and the mass elongates, a bright red spot appears near 
the clear end, and usually also, one or more clear seeming vacuoles 
are seen to arise within the green mass. The red spot has been 
called an eye, and the vacuoles stomachs ; and in this way Ehren- 
berg was enabled to classify these forms as “ Polygastric Animal- 
cules.” The spirally-twisted forms have been placed in a separate 
genus, and in fact I have seen, in the way mentioned, developed 
from the cell-contents of a filament of (Edogonium, forms identical 
with several genera of “ Polygastric Animalcules.” After a little 
longer time the cell-contents have again changed in appearance so 
as to be coarsely granular, each granule being so large and distinct 
that it can readily be distinguished, and now the active motion of 
the mass ceases, and it takes on the static condition. This it does 
by increasing in size, elongating and losing its cilium and red 
“ eye ” spot, while the clear portion elongates, subdivides, and 
branches out and becomes fixed either to a full-grown filament of 
(Edogonium or some other submerged substance that may serve it 
as a support. Now the cell-contents become finely granular again, 
and arrange themselves against the cell- wall, which is thickened 
