Place a prepared slide of Giardia first under tlie low power and then under the high power of the microscope and observe tlie followilig characters.

i) Bilaterally symmetrical pear shaped body, with the anterior end rounded and tlie posterior end tapering. Its one surface is colivex and tlie other surface is concave with a sucking disc.

ii) Tlie protoplasm contai~is two axostyles, two nuclei and four pairs of flagella arising from basal granules.