Coronal optical section through 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 (not seen 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 (seen well here). Single ovoid macronucleus lies just posterior to the vestibular area . Single posterior contractile vacuole (seen here overlaid by a food vacuole). Four food vacuoles contain ingested bacteria 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.