Polydesmus angustus, histological sections from anterior (A) to posterior (D) A articulation of tentorial transverse bar to head capsule B tentorial transverse bar and epipharyngeal bar C tentorial hypopharyngeal bar and posterior process D articulation of tentorium to “Nebententorium”. Abbreviations: a2 = medial antennal muscle, a3 = lateral antennal muscle, a4 = anterior antennal muscle, asd = duct of anterior salivary gland, asg = anterior salivary gland, co = collum, eb = epipharyngeal bar of tentorium, gl = mandibular gnathal lobe, gls = gnathal lobe sclerite, hb = hypopharyngeal bar of tentorium, m1 = gnathal lobe sclerite muscle, m4 = anterior mandibular cardo muscle, m5 = posterior mandibular cardo muscle, mc = mandibular cardo, mes = median septum, mg = mandibular gnathal lobe, ms = mandibular stipes, nt = ‘Nebententorium’, pc = preoral chamber, ph = pharynx, po = ‘Presshöcker’, t1 = anterior tentorial muscle, t2 = dorsal tentorial muscle, tb = transverse bar of tentorium. Scale bars: 200 µm.