134 
THE YOUNG SCIENTIST. 
Different specimens and species of Vor- 
ticellce vary in the length of their bells 
from one, three or four thousandth to 
one hundred and twentieth of an inch, 
and when they are tolerably large, the 
dark ground illumination produces a 
beautiful effect. The bells shine with a 
pearly iridescent lustre, and their cilia 
flash with brilliant prismatic colors. 
The .VorticeUina belong to the upper 
division of the Protozoa— the ciliata, or 
ciliated animalcules, and they have a 
mouth, an oesophagus, and an orifice for 
the exit of their food. 
Vorticella microstoma, 
showing alimentary 
tube, ciliated mouth, 
and formation of a 
gemma at the base, 300 
Mnetir— Stein. 
Vorticella microstoma, 
the encysted animal 
protruding through a 
supposed rupture of 
the tunic. 
of individual life. They are also capable 
of becoming encysted, that is, of secreting 
a gelatinous cover. 
Many observers used to ascribe to those 
creatures a complete intestinal canal, but 
such an apparatus is now believed not to 
exist in any of the Infusoria. Food parti- 
cles, after leaving the oesophagus, are 
thrust forward into the sarcode, or soft 
flesh, and any cavity thus formed acts as 
a stomach. 
The bells or cups are not, as might 
be fancied from a casual inspection, open 
like wineglasses at the top, but furnished 
with a retractile disk or cover, on which, 
the cilia are arranged. Their stalks are 
not simple stems, but are hollow tubes, 
which in the genus Vorticella are fur- 
nished with a muscular band, by whose 
agency the movements are principally 
made. 
Some of the Vorticellids will be ob- 
served to leave their stalks, having de- 
veloped cilia round their base, and may 
be seen to swim about in the enjoyment 
Encysted Vorticelhi, showing the obliteration 
of special oi-gans by the advancement of the 
process.— Pri^c/iaj-d 
These changes are exhibited in the an- 
nexed cuts, which are copied from known 
authorities. By careful observation of 
the bodies of Vorticellids, a contractile 
vesicle may be observed, which appears 
to cause a movement of fluids, that is 
probably connected either with respira- 
tion or secretion. 
Another piece of apparatus in this 
family, but not confined to it, is the so- 
called nucleus, which in this case is of a 
horseshoe shape and granular texture, 
and greater solidity than the surrounding- 
parts. The functions of this organ formed 
the subject of various conjectures, but it 
is now generally held to be an ovary. 
In common with many of the lower 
animals the Vorticellids have three ways 
of multiplying their race. One by fission, 
or division of their bodies ; another by 
buds, somewhat analogous to those of 
plants ; and another by reproductive 
Vorticella microstoma, in process of encyst- 
ment, bOO linear; in the last the inclosing tunic is 
plainly developed,— >S^em. 
germs. These processes will come again 
under our notice, and we shall leave the 
Vorticellids for the present by observing 
that if they are fed with a very small 
quantity of indigo or carmine, the vacu- 
oles or spaces, into which their nutriment 
passes, will be clearly observed. Ehren- 
berg thought in these and similar crea- 
tures that every vacuole was a distinct 
stomach, and that all the stomachs w^ere 
