Portrait of the intramacronucleate ciliate, Plagiopyla nasuta
(Stein, 1860). The distinctive vestibular region appears as a transverse ciliated furrow leading to a tubular oral cavity. The single ovoid macronucleus lies just posterior to the vestibular area. There is a single posterior contractile vacuole. Plagiopyla
is amitochondriate, instead possessing cytoplasmic hydrogenosomes in close association with endobiotic methanogenic bacteria. From bottom sediment of organically enriched standing freshwater near Boise, Idaho. Brightfield.