(vort-ee-sell-a) the iconic peritrich ciliate. The feeding cells in sessile peritrich ciliates have lost all of the somatic cilia and only have the feeding cilia. The feeding cilia form a wreath which extends around the front of the cell and descends into a narrowing buccal cavity. This cavity ends at the cytostome where food is packaged into food vacuoles. If the cells become unhappy, they produce a temporary wreath of basal cilia (trochal cilia), break away from their stalk and use these to swim. The stalk contains a contractile filament, and when this contracts it coils up a bit like a spring. Cells with expanded form are usually referred to the species V. campanula
. Phase contrast.