566 
THE LOWEST ANIMALS. 
oral cilia set up currents which 
converge to the mouth-funnel, 
and carry in other infusoria, 
diatoms, etc. 
T1 ie bell-animalcules usually 
possess stalks, and are either 
solitary or form branching colo¬ 
nies. Vorticella, whose outline 
is like that of a wine-glass, is 
provided at the rim with an 
incomplete circlet of cilia, one 
end of which passes down into 
the mouth-funnel at the margin 
(r) of the disc; the stalk con¬ 
tains a contractile band (m) 
which produces a rapid jerking 
motion by throwing the stem 
into coils; in the body-mass lie 
the nucleus ( n ) and contractile 
vacuole (v). Reproduction takes 
place by transverse division into 
two. Ehrenberg observed twelve 
individuals to originate from one 
within twenty - four hours, so 
that, calculating on this basis, 
one million individuals would be 
produced within twenty days. 
The common-branched bell-ani¬ 
malcule ( Carchesium ) divides 
more rapidly, namely, once in an 
hour; each again being soon 
ready for division, so that one 
thousand could arise in ten hours, 
and a million in twenty hours; 
but, as a matter of fact, only 
two hundred have actually been 
observed to have been formed in 
one day, owing to the intervals 
between successive divisions be¬ 
coming longer. The vigour of 
the exhausted stock becomes 
rejuvenated, however, by the 
fusion or conjugation of two 
individuals into one. 
The nodding bell-animalcule 
rosel’s trumpet-animalcule, Stentor (magnified 200 diameters). ( Epistylis ) forms little brandling 
