Genus: Body ellipsoid; anterior end truncate; posterior end rounded; peristome wide and V-shaped; a large membrane on right edge and adoral zone on left; macronucleus moniliform (Kudo, 1966). Species: Cell body elongate, 300 μm long, anterior broad and flat, posterior rounded, peristome wide, macronucleus large sausage in shape, no contractile vacuole ?, kineties spiral around the body (Carey, 1992).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

* C. psammophilum Bock, 1952: Cell body elongate, 300 μm long, anterior broad and flat, posterior rounded, peristome wide, macronucleus large sausage in shape, no contractile vacuole ?, kineties spiral around the body (Carey, 1992).

C. arenarium Spiegel, 1926: Cell body elongate, cylindrical, reached 600 μm long, posterior rounded, peristome short and wide, macronucleus moniliform, mucocysts present, no contractile vacuole ? (Carey, 1992). 400-700 μm long (Kahl).

C. minima (Dragesco, 1954) Dragesco, 1960: Cell body ovoid rather than elongate, 130 μm long, peristome wide, deep and almost ovoid, with large membranelles, macronucleus moniliform, a contractile vacuole with satellites, mucocysts present (Carey, 1992).

C. vastum Bock, 1955: Cell body ovoid, 180 μm long, anterior truncated, peristome wide triangular, posterior rounded with a slight bump terminal, three large macronuclei, no contractile vacuole ?, kineties spiral (Carey, 1992).

C. nigra Dragesco, 1960: cell body ovoid, rounded at both ends, 300 μm long, peristome small, but undulating membrane large, macronucleus moniliform, contractile vauoles along both edges of the body, dark blue mucocysts present (Carey, 1992).