| Description of Vorticella convallaria: Stalked, sessile peritrich ciliate; body 30-120 micrometres long, pedicle 100-500 micrometres. Bell-shaped, somewhat conical body, usually twice as long as it is broad; light in colour, often yellowish. Peristomial lip slightly rolled over. Pellicle with transverse ridges (annulations). Stalk relatively thick, containing spasmonemes that enable it to contract with extreme suddenness. The contracted stalk is helical. Macronucleus long, vermiform, often J-shaped. Found in large groups. Freshwater in stagnant conditions. |