Rhabdostyla invaginata Stoke 1886

— Fig. 3, U

Diagnosis: Size about 35µm. Vasiform body, rarely gibbus, twice as wide as long. Pellicle distinctly ringed. Peduncle with a 1/3 to 2/5 of body length. Peristomial collar not detached. Prominent ciliary disc, conical, with two ciliary circles. Expanded peristome, with a flat peristomial disc. Contractile vacuole near the peristomial region. Epibionts of ostracods, of the genus Cypris .

Remarks: diagnosis according to Stokes (1886).According Stokes, the contracted body is oval and the peduncle invaginates into the posterior extremity, causing the zooid to make real contact with the surface of the object that supports the stalk.