INFUSORIANS . 
565 
lobster, is an elongated worm-like organism about two-thirds of an inch in length; it 
multiplies by becoming a spherical cyst, the contents of which break up into minute 
spore-like bodies with spindle-shaped cases, 
which are set free on the bursting of the 
cyst. Each of the spore - bodies also 
ruptures and liberates an amoeba - like 
organism, which ultimately develops into ? 
an adult gregarina. Another species of 
gregarina lives in the intestines of the 
earth - worm. The Sporozoa are oval or 
spherical monad - like bodies, but without 
flagella, and live as parasites in the cells 
of plants and animals. Cancer and certain 
forms of malaria have been attributed to 
the presence of organisms of this nature in 
the fluids and tissues of the body. 
Ciliated Infusoria,— Order Ciliata. 
The organisms of this 
group are provided with 
cilia, limited either to the 
under side of the body, or 
forming a circle or spiral 
at one end, or arranged 
uniformly over the sur¬ 
face. Cilia are slender 
hair-like processes of the 
body, which move by 
bending and straighten¬ 
ing themselves in unison ; 
flagella are larger whip¬ 
like organs, and act more 
independently, the range 
of motion is not so re¬ 
stricted, and there are usually only one or two present on a 
cell. A few typical and common species are described. 
The mussel-animalcule (Stylonychia), common in stagnant 
water, has the flattened oval body one-hundredtli of an inch in 
length; on the under side is a ring of cilia, and at one end a 
funnel-shaped depression or mouth (a) with ciliated margin, 
leading through the dense outer protoplasm into the more 
BEI.L-ANIMALCULE ( Vorticella). 
a, Slightly magnified ; b, Magnified 600 diameters ; 
n, Nucleus ; m. Muscle-band. 
NODDING BELL-ANIMAL¬ 
CULE, Epistylis 
(nat. size = 
inch). 
fluid inner mass. The two dark oval bodies (c) are nuclei, 
and the clear spot ( b ) is the contractile vacuole which contracts 
rhythmically once in about every ten seconds. The creature can stalk along on 
the large bristle-like processes, in addition to swimming by means of its cilia; the 
