Vorticella can first be seen by the naked eye, b.ut to study it place a prepared slide under the microscope. Focus it under low power, and observe it. You can see a large number of specimens attached to aquatic plants or some object by thread-like contractile stalks. Tliey appear like tiny balloons attached by strings. Now focus tlie slide under tlie high power of the microscope, and study tlie following cliaraclers carefully:

i) Vorticella has bell-shaped body with a long slender and conitractile stalk for attachment.

ii) Tlie free broad end of tlie body is the oral end, while the opposite narrow end is the aboral end.

iii) Tlie entire body is covered by a thin pellicle and the protoplasm is clearly distinguisliable into an outer ectoplasm and an inner'endoplasm.

iv) The bell margin is fringed with a circle of cilia, while tlie central Inass forms the peristomial disc, wliicli is separated from tlie margin by a sliallow circular depression called oral groove or peristome.

v) On one side of tlie groove the peristomial groove is extended into tlie interior of tlle bell forming a vestibule or tlie buccal cavity. At tlie inner end, the vestibule opens through the cytostome into the cytopharynx.