PHYLUM PROTOZOO: CILIATA, PIROPLASMASIOA AND SPOROZOA
Section I. CLASS CILIATA
These organisms use small, hair-like structures called cilia (singular: cilium) for
locomotion. The outer envelope of the organism is a tough but flexible area called the
pellicle. Food absorption is carried out by gathering food particles with the cilia and
forcing them down the gullet (cytostome), where a vacuole is produced which surrounds
the food. Digestion is accomplished by internal enzymes. Excretion of the unused food
is accomplished by expulsion through the anal pore (cytopyge).
RESPIRATION AND REPRODUCTION
Hydrostasis with the environment is controlled by a pair of contractile vacuoles.
Respiration is performed by diffusion through the cell membrane. Reproduction may be
attained by simple cell division or by a complex exchange of genetic material between
two individuals. There is only one member of this class which is pathogenic to man:
Figure 2-1. Typical ciliate.