10 ANIMAL LIFE 
which are fine processes of-the dense protoplasm of the 
surface. There is on one side an oblique shallow groove 
that leads to a small, funnel-shaped depression in the body 
which serves as a primitive sort of mouth’ 
Yy or opening for the ingress of food. 
~ The Paramecium swims about in the 
water by vibrating the cilia which cov- 
er the body, and brings food to the 
mouth opening by producing tiny cur- 
rents in the water by means of the 
cilia in the oblique groove. The food, 
which consists of other living Proto- 
zoa, is taken into the body mass only 
through the funnel-shaped opening, and 
that part of it which is undigested is 
f= _ thrust out always through a particular 
part of the body surface. (The taking 
in and ejecting of foreign particles can 
be seen by putting a little powdered 
= carmine in the water.) Within the 
body there are two nuclei and two so- 
called pulsating vacuoles. These pul- 
Fie. 5.—Paramaciumau-  sating vacuoles (Ameba has one) seem 
relia (after VERWORN). 7s . c 
‘At each end there iaa +0 aid in discharging waste products 
contractile vacuole,and from the body. When the Parame- 
in the center is one of ° . 
ite waelal: cium touches some foreign substance or 
is otherwise irritated it swims away, 
and it shoots out from the surface of its body some fine 
long threads which when at rest are probably coiled up in 
little sacs on the surface of the body. When the Para- 
mecium has taken in enough food and grown so that it 
has reached the limit of its size, it divides transversely into 
halves as the Am@ba does. Both nuclei divide first, and 
then the cytoplasm constricis and divides (Fig. 6). Thus 
two new Paramecia are formed. One of them has to de- 
velop a new mouth opening and groove, so that there is in 
os 
a 
* go ae 
Bed 
on 
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