 
 
|  Genus: Colonical when mature; macronucleus long, often C-shaped; some species loricate
 (Illustrated Guide, 1985).  Stalk non-contractile. Species: | 
 100 μm
 100 μm
 200 μm
 200 μm
 300 μm; x 200 :
 300 μm; x 200 : 
 50 μm
 50 μm
 100 μm
 100 μm
 150 μm; x 400
 150 μm; x 400
 
 
 
O. ramosa: 140 μm long (How to know the protozoa, 1979).