Zoosphaerium sp., light micrographs of peristomatic structures. A Epipharynx, showing absence of the tentorial transverse bar B Preoral chamber, frontal view on hypopharynx (mandibles removed) C Hypopharynx and endochilarium, dorsal view (hypo- and epipharyngeal bar of right tentorium broken off). Scale bars: 500 µm. Abbreviations:eb = epipharyngeal bar of left tentorium; ed = endochilarium; ep = epipharynx; h1 = projection of hypopharyngeal bar; hb = hypopharyngeal bar of tentorium; hy = hypopharynx; il = incisura lateralis; lb = labrum; ll = lamella lingualis; lm = lamella-mentum; nt = nebententorium; ss = suspensorial sclerite; stg = stipes of gnathochilarium.