INFUSORIA. 
13 
to shew slight undulations ; the basal extremity of the 
stem is affixed to the support ; and the bell slowly roams 
about, with the length of its tether for a radius, now 
turning its open mouth, now its sides, and now its foot 
to the eye. 
On any shock, such as a tap with the nail on the stage 
or “ live-box,” — instantly, with the quickness of thought, 
so that the eye can scarcely trace the motion, the long 
stem is contracted into a beautiful spiral (b), suddenly 
bringing the bell close to the point of adhesion, when it 
immediately, but gradually (c), uncoils to its full length. 
It does not seem alarmed by tapping, except when fully 
extended ; for it we tap the box all the time it is unfold- 
ing, it does not shrink again, until it has reached its full 
extension, but then it does instantly. It frequently, how- 
ever, springs back again, when partially uncoiled, of its 
own accord, several times in succession. Hence we may 
presume that the spiral contraction is the result of alarm ; 
but that though alarm may be felt from the bell’s contact 
with substances in the water, or from currents, &c., at any 
time, a shock or tap produces this effect only when the 
stem is tense, and capable of vibration. The whole of the 
actions of this little animal are very sprightly and elegant. 
The ordinary increase of the animals of this class is by 
self-division. In the Vorticdlm it takes place in the fol- 
lowing manner : — Otie of the full-grown bells begins to 
alter its form, becoming first globular (£>), then a flattened 
sphere (c), presently a slight notch or depression is observed 
in the upper part of the outline, and it soon becomes 
apparent that this depression is a constriction extending 
all round, which gradually becomes deeper and more 
