Description of Vorticella campanula

Sessile peritrich ciliates, 50-160 micrometres long. Broadly bell-shaped, but variable in outline. Cytopasm with dense refractive granules, giving a dark or opaque central area in transmitted light. When fully opened, the peristome is wide, sometimes exceeding in diameter the length of the cell body. With peristomal lip, and large undulating membrane. Nearly spherical when contracted, with a puckered or warty appearance at anterior margin. Pellicle faintly annulated. Pedicle thick, 3 to 7 times as long as the body. Vermiform macronucleus, very long. Single contractile vacuole near cytopharynx. Common, widespread. Social, in uncontaminated freshwater ponds.