The putative spinning organ of the Glomeridesmidae, internal morphology of a mid-body leg of Glomeridesmus cf. sumatranus (SUM06/08 01), female, light microscopy. A, B: Mid-body leg stained with Toluidine blue. A: Overview, terminology for the musculature follows Manton (1961). B: Detail of the spinning field with the underlying tubuli, as indicated in A. C–G: Histological sections. C: Sagittal section through tarsus. D: Cross section through tarsus. E: Cross section through tibia. F, G: Sagittal sections through postfemur and femur. Abbreviations: cl = claw, fe = femur, gl = putative glandular tissue, m1 = depressor femoris, m2 = flexor femoris, m3 = flexor postfemoris, m4 = flexor tibiae, m5 = flexor tarsi, m6 = flexor unguiculi, pof = postfemur, prf = prefemur, sf = spinning field, ta = tarsus, ti = tibia, tu = tubuli.