Strobilidium caudatum showing late morphogenesis and division found in the benthic fresh water portion of the transitional estuarine Peconic River. I happened upon this dividing individual at the stage of "late divider". We can see the forming oral apparatus of the opisthe (the rear divider) with the AZM already formed in a pointed contracted bunch on the side of the proter (the forward divider). Within around ten minutes we can begin to see the formation of the opisthe body and the still motionless AZM of the opisthe. A bit later we see better definition between proter and opisth and now motion of the opisthe AZM. The organism darted away so I could not capture the separation. As you can see, the Strobilidium exhibits all of the behavioral characters described below by Petz and Foissner.

Oligotrich ciliates usually dominate marine planktonic ciliate communities. Although comparatively few species occur in freshwater, they also play an important role in the planktonic food webs of lakes. This fresh water Strobilidium species measured 85 um in length. Body is turbinate to inverted pyriform, slightly asymmetric, posterior end tapering and truncated, transverse section of the body is circular. Macronucleus horse shoe-shaped, close beneath zone of external adoral membranelles (external polykinetids), with opening in cytopharyngeal region. One spherical micronucleus adjacent to macronucleus. Contractile vacuole at left side in posterior third of cell. Feeds on diatoms and flagellates. Movement very rapid, rotating about main body axis. When undisturbed for a longer while, cell secretes a thin, mucous thread at caudal end (“scopula”), often very long, and attaches to a substrate. Thread hardly recognizable unless small particles adhere to it. Frequently, cells swing on the thread (“stalk”) in a waving motion, still rotating. Disturbed individuals detach immediately and dart away.

WOLFGANG PETZ and WILHELM FOISSNER. Morphology and Morphogenesis of Strobilidium caudutum (Fromentel),
Meseres corlissi N. Sp., Halteria grandinella (Muller), and Strombidiulm rehwaldi N. Sp., and a Proposed Phylogenetic
System for Oligotrich Ciliates (Protozoa, Ciliophora)'. J. ProtozooL. 39(1), 1992, pp. 159-176