Portrait of left (ventral) surface of Plagiopyla nasuta
(Stein, 1860), a sapropelic plagiopylid ciliate. The body is reniform. Distinctive vestibular region appears as a transverse ciliated furrow leading to a tubular oral cavity (seen well here). The somatic ciliature is dense and uniform. On the right (dorsal) surface a distinctive transversely striated pellicular channel bows anteriorly from the peristome then turns posteriorly (not seen in this left view). Single ovoid macronucleus lies just posterior to the vestibular area (seen here overlaid by a food vacuole). Single posterior contractile vacuole (not seen here). Plagiopyla
is amitochondriate, instead possessing cytoplasmic hydrogenosomes in close association with endosymbiotic methanogenic bacteria. From bottom sediment of organically enriched standing freshwater near Boise, Idaho. DIC optics.