Family : Trichomonadidae

• Body is usually pyriform, with rounded anterior and ponted posterior end.
• Single nucleus is present in anterior part of the body and anterior to which is blepharoplast from which 3-5 anterior flagella and a posterior flagellum arises
• Posterior flagellum runs along the base of undulating membrane and often extends beyond the body. An accessory filament is associated with it.
• Filamentous costa arises from the blepharoplast and runs along the base of the undulating membrane.
• Parabasal body (Golgi apparatus) lies posterior to the blepharoplast.
• Clear, rod-like axostyle also arises from the blepharoplast and passes through the center of body to emerge from the posterior end. Anterior end of the axostyle is enlarged to form a capitulum. Anterior to the blepharoplast, a pelta arises from the capitulum.
• This family contain 3 important genera: Trichomonas, Tritrichomonas, Tetratrichomonas

Genus : Tritrichomonas

• Members of this genus have three anterior flagella and posterior flagellum and lack a pelta
• Several species occur in this genus, out of which ‘Tritrichomonas foetus’ is of veterinary significance. They cause infertility and abortion.

Species of tritrichomonas