Stein, 1862
Body broadly elliptical to slightly reniform, contractile, posterior dorsal half vaulted; dorsoventrally flattened. Cytostome in or anterior to mid-body on left. Two macronuclei, 1 micronucleus. Contractile vacuole subterminal in posterior dorsal portion. Somatic ciliary rows about 18-24 on ventral side; dorsal side very likely without cilia. Adoral zone of membranelles extending along anterior margin from mid-way on left to mid-body on right. Size in vivo about 100-130 x 50-70 µm. Kahl (1932) erected a new species for the population studied by Fauré-Fremiet (1924), P. faurei (dorsal side uneven, with bristle-like cilia). The specimens studied by Wailes (1943) belong apparently also to Peritromus faurei (Song and Wilbert, 1997).
Ref.: Hamburger and Buddenbrock (1911), Kahl (1932).